Working with Asbestos

Working with Asbestos

Asbestos dust/fibers can be very dangerous for the health when inhales as it may cause Asbestosis, a form of cancer to lungs and chest. AS long the Asbestos Worker is aware of this health risk and is able to work in a disciplined manner according the subsequent instruction, it cannot cause any harm to him and the environment.

Decontamination, enclosure, and exit procedures

Decontamination Facility (General Information)

The decontamination unit is installed and commissioned prior to any work commencing. The Decontamination procedures are clearly displayed at the Clean and Dirty end of the unit. The power is to be on with the water management facility running, the water hose is to be connected. The water drainage pipe works including filters are to be installed.

The unit is to be cleaned when in use on a daily basis and details of the cleaner, time of cleaning and Supervisors inspection are to be recorded in the site log.

No eating, drinking or smoking is allwed within the unit, and wherever onboard the Mike-Mike Facilities!

(Except as indicated in MMS Accomodation)

Preparing for entering a Contaminated Area

1.      Remove transit coverall (coloured) and leave on the clothing hooks provided within the purpose made “Clean” enclosure.

2.      Take RPE (Respiration Power Equipment) and enter the decontamination facility via the external door into the “Clean/Bersih” section.

3.      Remove personal underwear and exchange with the disposable set provided (T-shirt, socks, and short + towel). Put personal underwear temporarty in plastic bag along with the towel, and leave behind in clean section.

4.      Ensure that individual RPE (Respiratory Power Equipment) is serviceable, carry out and record the following checks:

·        Battery charge rate and charging socked sealed.

·        Hoses

·        Exhalation valve Leak (fit) Test

·        Face piece/visor

·        Straps and harness

·        Inhalation valve

·        Flow Rate

·        Belt Webbing

5.      Dress in disposable clothing (TYVEC) leaving head uncovered and put on safety shoes. Put on RPE and ensure a good ‘sealed” fit, by using the mirror.

6.      Pass through the shower section (without showering) into the “Dirty/Kotor” section.

7.      Put on additional PPE (hand gloves,safety helmets,safety harness etc.)

8.      Pass through the external door of the “Dirty/Kotor” section and proceed into the working closure.

Leaving the Enclosure

1.      Vacuum each other off in the work area with the HEPA vacuum cleaner (maintaining full PPE+RPE) and walk strictly into Dirty/Kotor section.

2.      Upon entering the Dirty/Kotor section, remove and dispose off hand gloves, pre-filters, disposable coverall, and underwear, and place in the waste container within the enclosure whereby still maintaining the RPE. Vacuum PPE; clean safety shoes, hands and RPE with wet sponge from water bucked of provided.

3.      From there proceed through the Unclean/Kotor section and into the shower section, still maintaining the RPE with the respirator motor left running.

DO NOT SWITCH OFF OR REMOVE RESPIRATOR

4.      Wet and shower hairline and face position of respirator. Fit shower cap to filter case and shower RPE filter case, webbing, and hose.

5.      Turn-off respirator motor, remove respirator, wipe clean, dry with cloth, and hang on adjacent hook. Completely shower body and shampoo hair. Pay particular attention to fingernails by brushing them with the nailbrush and soap provided.

6.      Exit shower section into “Clean” section and take RPE along.

7.      Place RPE on hook and dry yourself with towel provided in underwear set. Disposable towel are to be disposed of in container on the outside of the “Clean” Section.

8.      Dress in personal underwear and coloured transit coverall and fit new pre-filter to RPE, and place on charge in cabin.

COLORECTAL CANCER .... Adjuvant therapy

Adjuvant therapy

Despite substantial improvements in surgical technique and
postoperative care, colorectal cancer continues to kill 95 000
people in Europe alone each year.
Of the annual 150 000 newly diagnosed cases, about 80%
have no macroscopic evidence of residual tumour after
resection. More than half of patients, however, develop
recurrence and die of their disease. This is a result of occult
viable tumour cells that have metastasised before surgery and
which are undetectable by current radiological techniques (the
limit of detection of standard computed tomography is about
1cm3, equivalent to 109 cells).
Adjuvant treatment (chemotherapy and radiotherapy) has
developed as an auxiliary weapon to surgery and is aimed at
eradicating these micrometastatic cancer cells before they
become established and refractory to intervention. As the
presence of the primary tumour can exert an inhibitory
influence on micrometastases, theoretically the removal of the
tumour might stimulate growth of any residual cells, increasing
the proliferating fraction and rendering them more susceptible
to the cytotoxic effects of the widely used cytotoxic agent,
fluorouracil.
It is reasonable to predict therefore that the earlier
chemotherapy is started after surgery, the greater the potential
benefit, although this has not yet been formally addressed in
adjuvant trials. Implicit in this belief is a necessity for a
multidisciplinary effort between surgeon, oncologist, and the
community care team to provide seamless, streamlined cancer
care for the individual patient.
Pharmacology of fluorouracil
Fluorouracil has remained the cornerstone chemotherapy for
colorectal cancer for over 40 years. It is a prodrug that is
converted intracellularly to various metabolites that bind to the
enzyme thymidylate synthase, inhibiting synthesis of thymidine,
DNA, and RNA. Increasing understanding of the molecular
pharmacology of fluorouracil has led to the development of
strategies to increase its efficacy.
The first strategy to be tested was coadministration with the
immunostimulatory, antihelminthic drug levamisole, but despite
promising early results, recent trials have not convincingly
shown significant improvements in outcome compared with
fluorouracil alone. In addition, no persuasive mechanism for the
assumed synergism between fluorouracil and levamisole has
been found.
In contrast, addition of folinic acid increases and prolongs
the inhibition of the target enzyme (thymidylate synthase) and
seems to confer improved clinical outcome compared with
fluorouracil alone in advanced disease and when used in
adjuvant therapy.
The side effects of chemotherapy based on fluorouracil vary
according to the regimen (most commonly given as bolus
intravenously daily for 5 days every 4 weeks or bolus weekly).
They include nausea, vomiting, an increased susceptibility to
infection, oral mucositis, diarrhoea, desquamation of the palms
and soles, and, rarely, cardiac and neurological toxic effects

Established benefits of fluorouracil
based adjuvant chemotherapy
Early adjuvant trials were retrospective and underpowered and
failed to show any therapeutic benefit with respect to recurrence
rate or survival. In 1990, however, the results of the intergroup
trial were published. In this study 318 patients with stage B
colorectal malignancy were randomised for surgical treatment
alone or surgery followed by fluorouracil plus levamisole. In
addition, 929 patients with stage C malignancy received surgery
alone, surgery plus levamisole, or surgery plus fluorouracil and
levamisole. For these patients there was a 33% reduction in the
odds of death and a 41% decrease in recurrence among those
treated with fluorouracil plus levamisole compared with surgery
alone or surgery plus levamisole.
In contrast with levamisole, combining folinic acid with
fluorouracil is pharmacologically rational, and documented
benefit in advanced disease led to the logical extension of this
combination into adjuvant therapy. Three large randomised
adjuvant phase III trials produced confirmatory evidence of
improved, disease-free survival at three years and improved
overall survival in patients treated with fluorouracil plus folinic
acid, with a 25-30% decrease in the odds of dying from colon
cancer (or an absolute improvement in survival of 5-6%
compared with controls).
Recently a meta-analysis of updated individual data from all
unconfounded randomised studies of adjuvant chemotherapy
(including the above three trials) has been undertaken
(Colorectal Cancer Collaborative Group, unpublished). Overall,
there was a 6-7% absolute improvement in survival with
chemotherapy compared with surgery alone (SD 2.3, P = 0.01).
The analysis advised that on current evidence the combination
of fluorouracil plus folinic acid should be accepted as
“standard” adjuvant chemotherapy for patients with Dukes’s
type C colon cancer.
Controversies in adjuvant therapy
Despite convincing evidence that adjuvant chemotherapy
improves disease-free survival and overall survival in Dukes’s
type C colon cancer (an estimated six deaths prevented for 100
patients treated), several controversies surrounding the
application of this form of treatment still exist.
Length of treatment and optimal dose of fluorouracil plus
folinic acid
Lengthy adjuvant treatment has adverse effects on patients’
quality of life as well as financial implications. A recent North
American study, however, has shown that six months’ treatment
is as effective as 12 months’.
Determining the optimal dose is important: high dose
folinic acid is 10 times as expensive as low dose. This issue has
been addressed in the “certain” arm of the United Kingdom
Co-ordinating Committee on Cancer Research’s QUASAR
(“quick and simple and reliable”) trial (patients with Dukes’s
type C colon cancer). The trial uses the principle of
randomising according to certain or uncertain indication: if, for
a particular subgroup of patients the worth in receiving some
form of adjuvant chemotherapy is definitely established from
published randomised controlled trials (for example, patients
with Dukes’s type C colon cancer) then these patients are
randomised to the certain indication arm (with a choice of
different drugs and regimens); if, however, no definitive
evidence exists of worth in a particular subgroup (for example,
in patients with Dukes’s type B colon cancer or with rectal

cancer) then the patients are randomised into the uncertain
indication arm (chemotherapy v no chemotherapy). The results
from QUASAR’s certain arm show that neither high dose
folinic acid nor levamisole contribute to improved survvial.
Role of adjuvant chemotherapy in lower risk groups
Inadequate data exist on the effect of chemotherapy in stage B
colon cancer. The proportional reduction in annual risk is
probably similar for stage B and stage C patients. If the
proportional reductions in mortality are similar, the absolute
benefits in terms of five year survival would be somewhat
smaller for stage B patients than for stage C patients because of
lower risk of recurrence (perhaps two to three lives saved per
100 patients treated).
Patients with stage B cancers who have prognostic
indicators that suggest a high risk of recurrence (for example,
perforation, vascular invasion, poor differentiation) might
benefit proportionately more than patients with stage B cancer
without high risk indicators and these variables might define a
subgroup of patients who might merit adjuvant chemotherapy.
Little evidence exists, however, on the prognostic predictability
of these various features.
Use of adjuvant therapy in rectal cancer
Insufficient evidence exists to support the routine use of
systemic chemotherapy in either Dukes’s type B or type C rectal
cancer. Anatomical constraints make the rectum less accessible
to the surgeon, so it is much more difficult to achieve wide
excision of the tumour, and about 50% of recurrences are in the
pelvis itself rather than at distant sites. This means that locally
directed radiotherapy is a useful adjuvant weapon, and this has
been assessed for rectal cancer both before and after surgery.
In the largest trial of preoperative radiotherapy (the Swedish
rectal cancer trial), radiotherapy produced a 61% decrease in
local recurrence and an improvement in overall survival (58% v
48%) compared with surgery alone. Radiotherapy after surgery
seems to be less effective, even at higher doses, possibly because
of rapid repopulation of tumour cells after surgery or relative
hypoxia around the healing wound.
Only one trial, the Uppsala trial in Sweden, has directly
compared radiotherapy before and after surgery. Despite a
higher dose after surgery, a significant reduction occurred in
local recurrence rates among patients treated before surgery
(12% v 21%, P < 0.02).
Animal studies have suggested that fluorouracil may prime
the tumour cells and increase the cytotoxic effect of subsequent
radiotherapy. Some clinical data support the role of
chemoradiotherapy combinations in rectal cancer, but further
clinical evidence of benefit needs to be provided before this
treatment could be considered for routine use. The uncertain
arm of the QUASAR trial will help to resolve this issue.



Role of portal venous infusional therapy
Fluorouracil is an S phase specific drug, and yet its active
metabolites have a half life of about 10 minutes, which limits its
target, when given as a bolus, to the small fraction of cells in the
S phase at the time of administration. Infusional therapy can
therefore affect a greater proportion of cells. In addition, the
most common site for micrometastases after resection of a
colorectal tumour is the liver. In contrast with macroscopically
identifiable metastases of advanced disease, which derive their
blood supply from the hepatic artery, these micrometastases are
thought to be supplied by the portal vein. Therefore delivering
chemotherapy via the portal vein should provide high
concentrations of the drug at the most vulnerable site and lead
to substantial first pass metabolism, which should attenuate any
systemic toxicity. The established regimen for portal fluorouracil
in adjuvant therapy is a course of 5-7 days starting immediately
after surgery. A meta-analysis of 10 randomised trials showed a
4.7% improvement in absolute survival with portal venous
infusion therapy compared with surgery alone; however, the
confidence intervals were wide and the statistical benefit is not
robust. Indeed the AXIS trial, the largest single trial of portal
venous infusion to date, randomising 4000 patients after
surgery either to the infusion therapy or to observation alone at
five years, suggests no significant differences in overall survival.
Future role of adjuvant therapy
The use of adjuvant therapy in colorectal cancer over the past
40 years has centred on fluorouracil, alone and in combination,
and on the fine tuning of regimen and route of administration.
Current trials are considering new drugs (eg irinotecan and
oxaliplatin) and their sequencing, as well as innovative
techniques, such as immunotherapy and gene therapy. These
techniques will be considered in detail later in the series. Gene
therapy and immunotherapy are likely to function optimally,
however, when cellular load is low, blood supply is good, and
small clusters of cells are surrounded by effectors of the
immune system; these therapies may therefore be most suitable
as adjuvant therapy rather than for use in advanced disease.
All cytotoxic agents are rigorously tested and applied in
advanced disease before being used in adjuvant therapy. New
agents that are now entering adjuvant trials will be fully
described in the next article in this series.

Primary treatment—does the surgeon matter?

Primary treatment—does the surgeon matter?

The dominant factor contributing to the relatively poor
prognosis for colorectal cancer is the advanced stage of the
disease at the time of initial presentation: up to a third of
patients have locally advanced or metastatic disease, which
precludes surgical cure. Even in the patients who undergo
apparently curative resection, almost half die within five years.
In the west of Scotland, for example, about a third of 1842
patients presenting with colorectal cancer to seven hospitals
between 1991 and 1994 presented as emergencies. Potentially
curative resection was achieved in about 70% of patients
presenting electively; the curative resection rate was lower in
those presenting as emergencies. Five per cent of patients
admitted for elective surgery and 13% of those admitted as
emergencies died. Almost 60% of elective patients survived two
years, compared with 44% of patients admitted as emergencies.
These results are typical of population based studies in the
United Kingdom.

Variation among surgeons
Most surgeons acknowledge that the incidence of postoperative
complications varies widely among individual surgeons. It is
now almost 20 years since Fielding and his colleagues in the
large bowel cancer project drew attention to differences in
anastomotic leak and local recurrence rates after resection for
large bowel cancer.
In the original Glasgow Royal Infirmary study, which was
conducted in the 1980s, similar differences in postoperative
morbidity and mortality were noted. Furthermore, after
apparently curative resection, survival at 10 years varied
threefold among surgeons.
One might argue that these are historical data and therefore
bear little relevance to the current situation. In the current west
of Scotland study, however, although overall 33% of patients
presented as emergencies, the proportion varied among
hospitals from 24% to 41% and among surgeons from 10% to
50%.
Similarly, the proportion of patients undergoing curative
resection varied among surgeons from 45% to 82%;
postoperative mortality, in patients presenting electively, also
varied, from 0% to 17%. Several out of the 16 surgeons studied
performed less well than their colleagues.
Several factors apart from the individual surgeon’s skill
might influence these measurements of immediate and long



term outcome: case mix; surgical philosophy; assessment of
cure; quality of pathological reporting; other prognostic factors;
small numbers (see box). Despite these factors it seems likely
that the differences in the immediate postoperative morbidity
and mortality observed among surgeons in the above studies
are genuine. There have now been several analyses of
immediate outcome after colorectal cancer surgery, and in each
study, the results have been broadly comparable.
Effect of volume of surgery
Two explanations are possible for the differences in outcome
among surgeons—namely, the number of patients treated by
individual surgeons and whether these surgeons are specialists.
Although good evidence exists for other types of surgery
that volume of work is important, in colorectal cancer
convincing evidence that volume affects outcome is lacking. In
the Lothian and Borders study, 5 of 20 consultants were
responsible for 50% of the rectal cancer procedures. These five
surgeons had a significantly lower anastomotic leak rate, but this
may reflect specialisation rather than volume of work. In the
German multicentre study, a group of surgeons with low work
volume and performing only a few rectal cancer procedures
had local recurrence rates well within the range of results
obtained by individual surgeons with high work loads.
Furthermore, in a recent analysis of outcome in 927 patients
treated in the Manchester area, after correction for
non-prognostic variables no relation between volume and
outcome was noted.


Role of specialisation
The question of specialisation is more complex. Clearly rectal
cancer surgery represents a greater technical challenge than
colonic surgery. It therefore seems reasonable to expect—but it
is remarkably difficult to show (largely because of the small
numbers of patients treated by individual surgeons)—that
specialist surgeons achieve better outcome. Analysis of outcome
in almost 1400 patients with rectal cancer randomised in the
Swedish preoperative radiotherapy studies, suggested that local
recurrence and death rates were significantly lower in those
patients operated on by surgeons with more than 10 years’
experience as a specialist.


Perhaps the best information, however, comes from the
Canadian study in which 683 patients with rectal cancer were
treated by 52 different surgeons, five of whom were trained in
colorectal surgery. These five surgeons performed 109 (16%) of
the procedures. Independent of the type of training received by
the surgeons, 323 procedures (47%) were performed by
surgeons who each did fewer than 21 resections over the study
period. Multivariate analysis showed that the risk of local
recurrence was increased in patients treated both by surgeons
not trained in colorectal surgery and by surgeons performing
fewer than 21 resections. Similarly, disease specific survival was
lower in the patients treated by these two groups of surgeons.
These results suggest that both specialisation and volume may
be important independent factors determining outcome.
Surgeons are currently under intense scrutiny, partly
because readily available measures of outcome exist and partly
because outcome seems to differ substantially among surgeons.
The issues, however, are complex. Small numbers, annual
accounting, and failure to take into account case mix, surgical
intent, quality of staging, and prognostic factors may lead to
inappropriate conclusions.



Nevertheless, the results of the studies discussed here
suggest that some surgeons are less competent than their
colleagues and that these factors may compromise survival.
Considerable effort and resources are currently being poured
into large multicentre studies of adjuvant chemotherapy and
radiotherapy in an effort to provide a marginal improvement in
the survival of patients with colorectal cancer. If, by
specialisation, the overall results of surgery could be
improved—and evidence suggests that this is so—the impact on
survival might be greater than that of any of the adjuvant
therapies currently under study.

COLORECTAL CANCER .... The role of primary care

The role of primary care

Every general practitioner in the United Kingdom will on

average see one new case of colorectal cancer each year. For

most primary care doctors the most important contributions

they make to the care of patients with colorectal cancer relate to

early diagnosis of the condition (including the point of referral)

and to palliation of symptoms in those with established disease.

Further roles in the future primary care service are screening

for colorectal cancer (possibly using faecal occult blood testing)

and a greater involvement in monitoring patients after curative

procedures.

Early diagnosis and referral guidelines

Early diagnosis of colorectal cancer is essential in view of the

stage related prognosis. Three potential levels of delay occur in

the diagnosis of the disease: delay by the patient in presenting

to the general practitioner; delay in referral by the general

practitioner to a specialist; and delay by the hospital in either

establishing the diagnosis or starting treatment. Detrimental

differences between England and Wales and the rest of western

Europe in survival rates for colorectal cancer arise primarily in

the first six months after diagnosis, suggesting that these

differences relate to late presentations or delays in treatment.

Patients presenting with symptoms

Most patients developing colorectal cancer will eventually

present with symptoms. Primary symptoms include rectal

bleeding persistently without anal symptoms and change in

bowel habit—most commonly, increased frequency or looser

stools (or both)—persistently over six weeks. Secondary effects

include severe iron deficiency anaemia and clear signs of

intestinal obstruction. Clinical examination may show a definite

right sided abdominal mass or definite rectal mass.

Unfortunately, many large bowel symptoms are common

and non-specific and often present late. Recently published

guidelines, however, make specific recommendations about

which patients should be urgently referred—within two

weeks—for further investigation in the NHS. The guidelines also

indicate which symptoms are highly unlikely to be caused by

colorectal cancer.

The risk of colorectal cancer in young people is low (99%

occurs in people aged over 40 years and 85% in those aged

over 60). In patients aged under 45, therefore, initial

management will depend on whether they have a family history

of colorectal cancer—namely, a first degree relative (brother,

sister, parent, or child) with colorectal cancer presenting below

the age of 55, or two or more affected second degree relatives.

Patients aged under 45 presenting with alarm symptoms and a

family history of the disease should also be urgently referred for

further investigation.

In patients suspected of having colorectal cancer, referral

should be indicated as urgent (with an appointment expected

within two weeks); the referral letter should include any relevant

family history and details about symptoms and risk factors. An

increasing number of general practitioners will have direct

access to investigations, often via a rapid access rectal bleeding

clinic. The usual investigations needed will be flexible

colonoscopy or barium enema studies.

In the absence of a family history of the disease, younger

patients with a negative physical examination, including a

digital rectal examination, can be initially treated

symptomatically. If symptoms persist, however, patients should

be considered for further investigation.

Patients with genetic predisposition

All patients registering with a practice for the first time should

provide details of their medical history. Patients with a history of

familial adenomatous polyposis should be referred for DNA

testing after the age of 15. Familial adenomatous polyposis

accounts for about 1% of cases of colorectal cancer, with the

defect gene identified on chromosome 5. Patients with a

positive result should enter a programme of surveillance with

flexible sigmoidoscopy.

The second common genetic predisposition to colorectal

cancer is hereditary non-polyposis colon cancer. This condition

should be suspected in patients describing three or more cases

of colorectal cancer (or andenocarcinoma of the uterus) within

their family. Such patients should be referred for endoscopic

screening at the age of 25. Genetic testing for this condition is

currently not feasible.

In patients with a first degree relative with colorectal cancer

aged under 45 or with two first degree relatives with the disease,

the lifetime risk of the cancer rises to over 1 in 10. Such patients

should be referred for lower endoscopy screening once they are

10 years younger than the age at which the disease was

diagnosed in the youngest affected relative. An earlier article in

this series gives more detail on the genetics of colorectal cancer.

Population screening in primary care

The United Kingdom currently has no national screening

programme for colorectal cancer. Several studies in the United

States and Europe have shown that screening with faecal occult

blood testing will reduce the overall mortality of colorectal

cancer by about 15%. Such testing is a fairly simple procedure:

only two small samples from different sites of a stool need to be

collected on each of three consecutive days. In the United

States, the specimens are then normally hydrated, whereas

research in the United Kingdom and Denmark advocates using

dry samples. The latter technique results in a lower sensitivity,

but higher specificity—desirable test performance characteristics

for an asymptomatic population screening procedure.

Faecal occult blood testing is therefore a cheap and easy

method of screening, with reasonable levels of acceptability to

the population. The main disadvantages of this test are the low

sensitivity—with about 40% of cancers missed by a single screen,

leading to the need for frequent faecal occult blood tests—and

the fact that bleeding tends to occur late in the development of

the disease. Furthermore there are no direct studies to guide on

the most cost effective method of establishing a national

screening programme using faecal occult blood testing.

However, evidence from the cervical screening programme

suggests that general practice led “call/recall” programmes

would have the greatest impact.

A large Medical Research Council trial is currently

evaluating once-only flexible sigmoidoscopy as a method of

screening patients aged 50-60 years. The results of this trial will

not be available for several years.

The American Cancer Society recommends an annual

digital rectal examination for people aged over 40, an annual

faecal occult blood test for people aged over 50, and flexible

sigmoidoscopy every three to five years for people aged over 50.

More detail on screening for colorectal cancer appears in an

earlier article in this series.

Managing patients with established

disease

After confirmation of diagnosis, the role of the primary care

doctor revolves around advice, support, possibly monitoring for

recurrence, and palliative care. Some general practices are

involved with home based chemotherapy, usually coordinated

by specialist outreach nurses.

In the United Kingdom primary care does not currently

have a formal role in monitoring for disease recurrence after

curative treatments. Data on this option are limited (see a later

article in this series) but suggest that such surveillance could be

safely conducted in primary care. Ideally, this monitoring

should be accompanied by adequate infrastructure and training

in primary care, with good liaison between the practice and

secondary (or tertiary) care.

Limited evidence from other types of shared care indicate

that certain factors are likely to improve outcomes: structured

and planned discharge policies; the use of shared (preferably

patient held) cards that document patient information (disease

progress and drug treatments, as a minimum); locally agreed

guidelines specifying the appropriate follow up and delineating

responsibilities; and access to rapid referral clinics. As with

follow up in all chronic diseases, the more communication

between doctors and with the patients (and their families), the

better the quality of care.

Where appropriate, the doctor should also counsel patients

on any possible familial risk and the need for genetic

counselling of relatives. The primary care doctor may also

advise patients with diagnosed colorectal cancer about practical

considerations, including access to social security benefits. In the

United Kingdom eligibility for attendance allowance may be

immediately available in the exceptional circumstance of cancer

with a short terminal prognosis of less than six months.

For some patients, especially those with rectal tumours, the

diagnosis of cancer is also accompanied by the necessity for

either colostomy or ileostomy. Such patients will often require

further specialised support, and liaison between the primary

care team and specialist stoma nurses is important.

As the disease progresses, management will shift towards

palliative care. Ideally, this would be delivered jointly by the

primary care team and specialist palliative care services, such as

those based at a hospice or provided by Macmillan nurses. Few

data exist to guide on the most effective models for palliative

care in colorectal cancer. However, non-randomised studies

have shown high satisfaction among patients when they are

kept fully involved in understanding the progression of their

disease and their treatment options, when shared care cards are

used, and when home care teams are provided.

The main priorities in palliative care in colorectal cancer

include the management of pain, jaundice, ascites, constipation,

and nausea. The importance of attempting to correct these

symptoms cannot be overstated: as much distress may be

caused by constipation or nausea as by pain. Full explanations

of signs such as jaundice are likely to be reassuring. Moreover,

the advent of specialist home care teams (with access to

specialist equipment—such as bed aids to preserve pressure

areas or syringe drivers for pain control) and skilled counsellors

for patients and their families, enables virtually all patients who

wish it to remain at home.

Such an option is further enhanced by relief admission—

when necessary for the patient or the family—to specialist

palliative care wards or, more likely, to a hospice. In the

United Kingdom only a minority of patients with colorectal

cancer currently die from their disease in hospital or in a

hospice.

COLORECTAL CANCER .... Screening

Screening

Colorectal cancer is the third commonest malignancy in the
United Kingdom, after lung and breast cancer, and kills about
20 000 people a year. It is equally prevalent in men and women,
usually occurring in later life (at age 60-70 years). The incidence
of the disease has generally increased over recent decades in
both developed and developing countries. Despite this trend,
mortality in both sexes has slowly declined. This decrease in
mortality may reflect a trend towards earlier diagnosis—perhaps
as a result of increased public awareness of the disease.

Why screen?
Most colorectal cancers result from malignant change in polyps
(adenomas) that have developed in the lining of the bowel
10-15 years earlier. The best available evidence suggests that
only 10% of 1cm adenomas become malignant after 10 years.
The incidence of adenomatous polyps in the colon increases
with age, and although adenomatous polyps can be identified in
about 20% of the population, most of these are small and
unlikely to undergo malignant change. The vast majority (90%)
of adenomas can be removed at colonoscopy, obviating the
need for surgery. Other types of polyps occurring in the colon—
such as metaplastic (or hyperplastic) polyps—are usually small
and are much less likely than adenomas to become malignant.
Colorectal cancer is therefore a common condition, with a
known premalignant lesion (adenoma). As it takes a relatively
long time for malignant transformation from adenoma to
carcinoma, and outcomes are markedly improved by early
detection of adenomas and early cancers, the potential exists to
reduce disease mortality through screening asymptomatic
individuals for adenomas and early cancers.
Which screening test for population
screening?

Education about bowel cancer is poor. A survey in 1991 showed
that only 30% of the British population were aware that cancer
of the bowel could occur. Such ignorance only adds to the
difficulties of early detection for this form of cancer.
For a screening test to be applicable to large populations it
has to be inexpensive, reliable, and acceptable. Many different
screening tests for detecting early colorectal cancer have been
tried. The simplest and least expensive is a questionnaire about
symptoms, but this has proved predictably insensitive and
becomes reliable only when the tumour is relatively advanced.
Digital rectal examination and rigid sigmoidoscopy both suffer
from the limitation that they detect only rectal or rectosigmoid
cancers and are unpleasant and invasive.

Flexible sigmoidoscopy


Flexible sigmoidoscopy can detect 80% of colorectal cancers as
it examines the whole of the left colon and rectum. A strategy of
providing single flexible sigmoidoscopy for adults aged 55-65
years—with the aim of detecting adenomas—may be cost
effective. A multicentre trial of this strategy for population
screening is currently under evaluation.
Although flexible sigmoidoscopy is more expensive than
rigid sigmoidoscopy, it is generally more acceptable to patients
(it is less uncomfortable) and has much higher yield than the

rigid instrument. Many nurses are now trained to perform
flexible sigmoidoscopy, making potential screening
programmes using this technique more cost effective. In a
population screening programme, uptake of the offer of the
screening test is crucial. Uptake is likely to be around 45%, and,
of these, 6% will subsequently need full colonoscopy. The effect
that this will have on the incidence of and mortality from
colorectal cancer is uncertain until the completion of the
multicentre trial in 2003.
Colonoscopy
Colonoscopy is the gold standard technique for examination of
the colon and rectum, but its expense, the need for full bowel
preparation and sedation, and the small risk of perforation of
the colon make it unacceptable for population screening.
Colonoscopy is, however, the investigation of choice for
screening high risk patients (those at risk of hereditary
non-polyposis colon cancer or with longstanding ulcerative
colitis).


Barium enema
Barium enema, like colonoscopy, examines the whole colon and
rectum, and, although it is cheaper and has a lower
complication rate than colonoscopy, it is invasive and requires
full bowel preparation. Whereas colonoscopy may be
therapeutic (polypectomy), barium enema does not allow
removal or biopsy of lesions seen. There are no population
screening studies using barium enema.
Faecal occult blood tests
Faecal occult blood tests are the most extensively studied
screening tests for colorectal cancer. These tests detect
haematin from partially digested blood in the stool. Their
overall sensitivity for colorectal neoplasia is only 50-60%,
though their specificity is high. In screening studies of faecal
occult blood tests, individuals are invited to take two samples
from each of three consecutive stools. Compliance is around
50-60%, but with population education this might be improved.
Individuals with more than four out of six positive tests (about
2% of participants) need colonoscopy.
Several large randomised studies have shown that screening
with faecal occult blood testing is feasible, and two studies have
shown that such screening reduces the mortality from
colorectal cancer. In a study in Nottingham, for every 100
individuals with a positive test result, 12 had cancer and 23 had
adenomatous polyps. The cancers detected at screening tended
to be at an earlier stage than those presenting symptomatically
(Dukes’s A classification: 26% screen detected v 11% in
controls). The disadvantage of screening with faecal occult
bloods is its relatively low sensitivity—a third to a half of cancers
will be missed on each round of screening. The Nottingham
data suggest that screening every two years detects only 72% of
cancers. This could be improved by testing annually and using
more sensitive immunologically based faecal occult blood tests.
Who should be screened?
Although about 20% of the population will develop
adenomatous polyps, only 5% of these will develop colorectal
cancer. This equates to a 1 in 20 lifetime risk for colorectal
cancer. The cancer occurs most often in the age group 65-75
years, but for adenomas the peak incidence is in a slightly
earlier age group (55-65 years). Thus population screening for
colorectal cancer should target both these age groups.
In addition, some people inherit a much higher
susceptibility to colorectal cancer. Some inherit a well

recognised single gene disorder, such as familial adenomatous
polyposis or hereditary non-polyposis colon cancer, whereas
most inherit an undetermined genetic abnormality. These
people tend to develop colorectal cancer before the age of 50,
and therefore screening in this high risk population needs to be
tailored to each individual’s risk pattern. They may also be at
risk for cancers at other sites, and screening for ovarian, breast,
and endometrial cancers may be appropriate in some of these
cases. The advice of clinical geneticists in these cases can be
invaluable.


Cost effectiveness of screening
If screening for colorectal cancer is to be acceptable to
healthcare providers it must be shown to be cost effective.
Estimates of the cost of screening for colorectal cancer range
from £1000 to £3000 per life year saved, depending on the
screening technique used. The cost of using faecal occult blood
testing would be the lowest—similar to estimates for breast
cancer screening.
Cost estimates are associated with several unknown factors.
The factors that cause greatest concern to those considering
funding screening programmes are the cost of cancers missed
and the potential damage caused to asymptomatic individuals
by invasive procedures such as colonoscopy.
Potential harm from screening
Although it has been suggested that considerable anxiety and
psychological morbidity may be caused by inviting populations
to participate in screening for colorectal cancer, little evidence
exists to substantiate this. Indeed in the Nottingham trial no
longstanding psychological morbidity from the screening
programme was found. Similarly, no evidence exists that
screening for colorectal cancer leads to false reassurance from
negative tests.

Complications from colonoscopy (perforation and
haemorrhage), however, can occur. The incidence of these
complications is around 1 in 2000 procedures, and
complications usually occur in therapeutic colonoscopy
(endoscopic polypectomy) rather than in diagnostic procedures.
Mortality from such events is rare.