Cancer Prevention and Screening
NHMRC Recommendations (Evidence-based):
1. Moderate physical activity 30-60 min / day
2. Weight in healthy BMI range.
3. Avoid smoking
4. Limit alcohol to 2/day
5. Reduce energy intake to <2500 calories / day (<2000 in
6. Reduce dietary fats to <25% of intake
7. Limit red meat to moderate intakes of lean meat
8. 5+ serves per day of vegetables and 2 for fruit
9. Poorly soluble fibres (e.g. wheat bran).
10. Adequate calcium intake
11. Aspirin reduces risk of polyps in those who have had an adenoma
Justification for Screening
Second most deadly cancer
Early pickup of polyps can prevent development of cancer.
American Cancer Society
Divide population into:
- average risk = 75%
- moderate risk = 20%
- high risk = 5%
Screen at 50 yrs
- annual PR exam
- fecal occult blood tests yearly
- flexible sigmoidoscopy every 5 yrs
- OR colonoscopy / double contrast enema every 5-10 yrs
1 or more 1st degree relatives
OR personal history of neoplasia
Screen at 40y, or 10y earlier than youngest affected relative's age
- colonoscopy every 5 years.
If pt has personal history of a significant adenomatous polyp
- colonoscopy annually until negative, then 5-yearly.
Hereditary or genetic predisposition
Like HNPCC or FAP, IBD >10y
Genetic counselling for family.
Surgical referral if prophylactic colectomy recommended as per
Essentially the same as the above.
1. FOB testing for all Australians over 50 years, at least once
every two years (strongly recommended)
2. Flexible sigmoidoscopy every 5y from aged 50 (equivocal)
Category 1 Risk
- one first degree relative with colorectal Ca diagnosed at
age 55 or over.
--> RR 2x
1. FOB testing every second year
2. Flexible sigmoidoscopy (or colonoscopy) every 5 years from aged
Category 2 Risk
- one first degree relative with colorectal Ca, diagnosed <55
--> RR 3-6x
Colonoscopy every 5 years, starting age 50, or 10y younger
than first diagnosis of bowel Ca in family.
If can't get a colo, then sigmoidoscopy and double-contrast Ba enema
Full family hx and update regularly for HNPCC possibility.
- routine genetic testing not currently appropriate.
- if Bethesda criteria met, Tumour testing for HNPCC-related changes
(immunohistochm and microsatellite instability)
Category 3 Risk
- two first degree relatives diagnosed at any age
--> RR 3-6x
Specialist genetic testing after counselling --> see below if dx
Else as for Category 2 risk.
Role of NSAIDs in prevention is unclear
If negative on genetics then obviously at average risk.
1. Total colectomy and ileorectal anastomosis or restorative
proctocolectomy recommended when ready for surgery
2. Surveillance should begin by age 12-15y, except in attenuated FAP
(then guided by colonoscopy)
3. Duodenal surveillance from age 25+
1. Annually or two yearly colonoscopy from age 25+
- or 5y before age at first cancer.
2. Surveillance for uterus and ovarian cancer at age 30-35, or 5y
earlier than youngest affected relative.
3. Use Revised Bethesda Guidelines for selection of cancers for MSI
testing and staining
Follow-up of Polyps
1. 1 year if tumour resected
2. 3 years if large adenomas or high grade dysplasia, or villous
adenoma, or 3+ adenomas, or aged 60+ with first degree relative
3. Else 5 years is fine.
See also more complete plan here