Evidence to suggest that sigmoidoscopy may be effective
for colorectal cancer screening, with benefits lasting
for up to ten years, has come from two case-controlled
studies (Selby et al., 1992; Newcomb et al., 1992). As
such studies cannot eliminate the effect of selection
bias, however, this benefit may have been overestimated.
Trials are now under way to evaluate flexible sigmoidoscopy
and colonoscopy for screening.
Several trials have evaluated the effect of the faecal
occult blood test (FOBT). A trial in Minnesota, United
States of America, used the FOBT annually in one group
and biennially in another. This initially indicated that
annual, but not biennial, FOBTs reduce mortality from
colorectal cancer after about a ten year period (Mandel
et al., 1993). A more recent report, with follow-up for
up to 18 years, showed mortality reduction at a lower
level from biennial screening (Mandel et al., 1999).
Trials in Europe also showed mortality reduction from
biennial screening (Hardcastle et al., 1996; Kronborg
et al., 1996).
It is clear that a major difficulty
with screening using the FOBT is lack of specificity,
especially if the test is rehydrated, which substantially
increases the costs of programmes. Further, there seems
to be a lack in sensitivity for detecting adenomas. Taken
together, the FOBT trials suggest that, after an interval
of about 10 years, there could be a reduction of up to
20% in colorectal cancer mortality from biennial screening,
and a greater reduction as a result of annual screening.
Unless high compliance with the test can be achieved,
however, the benefit that could be obtained in the general
population would be much less, and not commensurate with
the expense of the screening programme. (Source: WHO)
What do we know about diet
and colorectal cancer?
The Panel
of WCRF/AICR concludes (Chapter
7.10, pages 280-288): To
download the chapter
click here
The Panel concludes (page 295):
The evidence that physical activity protects against
colorectal cancer is convincing, although the evidence
is stronger for colon than for rectum.
The evidence that red meat, processed
meat, substantial consumption (more than about 30 g per
day ethanol) of alcoholic drinks (by men, and probably
by women), body fatness and abdominal fatness, and the
factors that lead to greater adult attained height, or
its consequences, are causes of colorectal cancer is
convincing.
Foods containing dietary fibre, as
well as garlic, milk, and calcium, probably protect against
this cancer.
There is limited evidence suggesting
that non-starchy vegetables, fruits, foods containing
folate, as well as fish, foods containing vitamin D,
and also selenium and foods containing it, protect against
colorectal cancer, and that foods containing iron, and
also cheese, foods containing animal fats, and foods
containing sugars are causes of this cancer.
Source: Second Expert Report:
Food, Nutrition, Physical Activity, and the Prevention
of Cancer: a Global Perspective. World Cancer
Research Fund / American Institute for Cancer Research
(WCRF/AICR), Washington DC: AICR, 2007. 537 Pages.
Note: PDF file of the complete report is 12 MB in size.
More about this report can be found on the “diet” link
[or some other name later] of this website. To download
the entire report (pdf 12MB) please
click here.
To download a summary of the report (16 pages, pdf 1.2MB) please
click here
To download the report’s summary
in other languages than English (WCRF website), please
click here
MedlinePlus
- Colorectal Cancer Link
MedlinePlus will direct you to information to help answer health questions. MedlinePlus
brings together authoritative information from NLM, the National Institutes of
Health (NIH), and other government agencies and health-related organizations.
MedlinePlus also has extensive information about drugs, an illustrated medical
encyclopedia, interactive patient tutorials, and latest health news. Please make
sure you check the MedlinePlus online for Colorectal Cancer with an extensive,
constantly updated resource list. Please
click here
Resources
The
resources listed here are organized by relevance.
They are published by well-known organizations working
on breast cancer. All PDF files listed can be downloaded
from the pacificcancer.org website, without having
to visit any other site.
