"Don't Die of Embarrassment"
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Mark Worwood talked about his retirement job
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BOWEL
CANCER
SCREENING
IN
WALES
Mark talks to Gemma after his presentation
EDUCATION & TRAINING
He
summarised his education and training at Portsmouth, Exeter University
and London University and how his scientific work had regressed from
the rather sophisticated Neutron Activation Analysis of trace metals to
the somewhat basic testing of poo samples! Most of his research career
in Cardiff has been concerned with iron in the body – how it is
absorbed, how to detect iron deficiency using the assay of serum
ferritin and the inherited, iron overload, condition of
haemochromatosis. This work involved much laboratory testing as well as
methods for population testing.
BOWEL CANCER
Next
followed a description of bowel cancer – incidence, pathology,
causes, diagnosis and treatment. It is second most common form of
cancer in the UK and affects both men and women. About 35,000 cases are
diagnosed each year with about 17,000 deaths from bowel cancer.
Treatment costs are estimated to be £1 billion. Screening the
population is justified because early detection allows effective
treatment and prolonged survival. In Wales we have benefited from the
experience gained in pilot studies in England and Scotland and have
received much help from those already providing screening.
POPULATION SCREENING
Screening
involves testing asymptomatic (apparently healthy) members of the
general public to identify those at risk of developing bowel cancer. He
explained the various ways in which this could be done and concluded
that the only practical method at present is the faecal occult blood
test – testing faeces for the presence of “hidden”
blood (ie very low amounts). This works because both polyps
(which may develop into cancers) and tumours tend to bleed into the gut
but, of course, there are other causes of bleeding into the lower gut.
The testing process is to send out a “guaiac” kit to all
Welsh residents aged 60 – 69 every two years. The age range will
gradually extend from 50 – 74. This test will detect any form of
haemoglobin (ie from bleeding but possibly from food). The
“guaiac” test requires participants to collect samples on
three days and then return the kit in a special envelope by post. If
blood is detected in all sample the participants is offered a
colonoscopy at a local hospital. If only 1 or 2 samples are positive
then a more specific kit is sent that detects only human haemoglobin
from bleeding in the bowel. If the result is positive, colonoscopy is
offered. The reason why the more specific test is not used initially is
largely because it is much more expensive.
WELSH ORGANISATION
There is a central office and laboratory at Llantrisant to
manage sending out test cards and letters as well as testing the
returned cards. There is also a help-line. Colonoscopists and nurses
are employed by the Screening Services in each major hospital Trust to
take participants through the process of investigation. Colonoscopy
not only makes it possible to detect cancers and polyps that may become
malignant but also allows the colonoscopist to remove such polyps and
so prevent cancer. Only when a diagnosis of cancer is made is
responsibility passed to the local Trust.
Mark reminded the group that screening can cause harm as well as preventing cancer so there have to be very strict standards of competence to ensure that produres are as safe as possible.
Mark reminded the group that screening can cause harm as well as preventing cancer so there have to be very strict standards of competence to ensure that produres are as safe as possible.
The bowel screening process: left to right –
1. screening (FOBT),
2. diagnosis (and treatment) by colonoscopy,
3. prognosis (pathology).
AIMS OF THE SCREENING PROGRAMME
The
aim of the programme sounds modest: “in the group of people
invited for screening we aim to reduce mortality from bowel cancer by
15 per cent by 2020”. Achieving this requires at least 60 % of
those invited to agree to take part. If this can be increased the
reduction in the number of deaths due to bowel cancer will be greater
and improvements in testing will lead to a further reduction.
Although Wales has started national screening 2 years after England and 18 months after Scotland we have now caught up as screening has been introduced throughout Wales whereas in England and Scotland some areas are not yet being offered screening. The population eligible for screening will rise from about 350,000 this year to 1 million in 2018.
Although Wales has started national screening 2 years after England and 18 months after Scotland we have now caught up as screening has been introduced throughout Wales whereas in England and Scotland some areas are not yet being offered screening. The population eligible for screening will rise from about 350,000 this year to 1 million in 2018.