How to Treat – Bowel cancer part 1 : Diagnosis
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Patients under 50 Discussion of screening still needs to occur with all adult patients over the age of about 20 . It is important to remember that patients classified as risk category two or three have , by definition , a significant family history of usually younger relatives who have been affected by colorectal cancer .
If discussion regarding screening options were to be delayed in all patients until the age of 50 , these high-risk patients would simply not be identified until well after the age at which they should have started screening . In addition , while the NBCSP only offers free FOBT to patients over 50 of average risk , up to 10 % of all new diagnoses of bowel cancer in Australia will occur in patients under the age of 50 . There is also evidence to suggest that this percentage is increasing .
It is perfectly reasonable for patients under 50 , even with a negative family history , to consider starting self-funded FOBT if they are aware of the risks , benefits and potential costs of undertaking this . Now there are a large number of third-party providers ( see online resources ) who provide FOBT kits at a relatively modest cost .
Remember that a strategy for bowel cancer screening , guided by the NHMRC guidelines , should occur in all of your adult patients .
Staged rollout of the National Bowel Cancer Screening Program
Australian doctors face a challenge between 2016 and 2020 in accommodating the currently incomplete rollout of the NBCSP . If patients currently enrolled in the NBCSP return a negative test , then the next kit will not be sent for up to five years .
This current structure is not yet fully consistent with the national guidelines . It is therefore important to discuss with patients who have returned a negative test under the NBCSP the option of self-funding one-to-two-yearly tests in the interim to ensure their screening requirements are optimised .
Other advice for patients about bowel cancer screening Educate all adult patients on the dietary and lifestyle guidelines for reducing the risk of bowel cancer ( see table 2 ). In addition , educate patients about the importance of a change in family history . Patients should alert their GP to a change in status if a family member is affected , and an annually updated systems review of all patients should include questions regarding a family history of colorectal cancer .
Lastly , GPs should educate patients about vigilance for interval symptoms between screening investigations , which include rectal bleeding , change in bowel habits , unexplained abdominal pain or weight loss .
Management of patients who have had adenomatous polyps The diagnosis of a polyp in a patient may significantly alter the advice that will be given regarding future screening strategies . It is
Sigmoidoscope .
important to stratify advice on the basis of the histopathology of the polyp , the discussion in consultation with the endoscopist and to do
Table 2 . General guidelines to reduce the risk of colorectal cancer
Category
Recommendation
Diet The risk of CRC can be reduced if patients do the following :
• Restrict energy intake ( fewer than 2500kcal a day for men ; fewer than 2000kcal a day for women )
• Reduce dietary fat ( less than 25 % of total energy as fat )
• Eat five or more portions of fruit and vegetables a day all year round
• Consume poorly soluble cereal fibres ( eg , wheat bran ), especially if at high risk of CRC
• Ensure a dietary calcium intake of 1000-200mg a day
• Reduce consumption of red and processed meats
Healthy lifestyle
The following healthy lifestyle recommendations may be protective against CRC and should be followed by all people :
• Participate in regular physical activity
• Restrict alcohol intake
• Do not smoke
Chemoprevention
Agents such as selenium supplements , aspirin , NSAIDs and selective COX-2 inhibitors may be important in the prevention of CRC , but are not recommended until further research is conducted
Type of polyps
Patients with only polyps , which are small , pale , distal and hyperplastic
High-risk adenomas : three or more adenomas Equal to or greater than 10mm or with tubulovillous or villous histology or high-grade dysplasia
Follow-up of patients with sessile adenomas and laterally spreading adenomas
Follow-up after resection of serrated adenomas and sessile serrated adenomas
Follow-up for patients with multiple adenomas
Follow-up based on two or more examinations
Table 3 . Guidelines for follow-up investigation after removal of polyps Colonoscopic follow-up None
Colonoscopy at three-yearly intervals
If large and sessile adenomas are removed piecemeal , follow-up colonoscopy should be at 3-6 months to ensure complete removal If removal is complete , subsequent surveillance should then be based on histological findings , size and number of other adenomas
Currently , insufficient evidence to differentiate follow-up protocols for sessile serrated adenomas from standard adenoma follow-up guidelines Follow-up should be determined as for adenomatous polyps , taking into account parameters , such as polyp size , number and presence of high-grade dysplasia
As multiplicity of adenomas is a strong determinant of risk of metachronous advanced and non-advanced neoplasia , follow-up should be at 12 months for those with five or more adenomas and , because of the likelihood of missed synchronous polyps being present , sooner in those with 10 or more adenomas If a polyposis syndrome accounts for the findings , follow-up colonoscopy should be within one year for patients with five or more adenomas at one examination
If advanced adenomas are found during subsequent surveillance , maintaining a three-yearly schedule is prudent , but the choice should be individualised The interval can be lengthened if advanced adenomas are not found
Source : Cancer Council Australia . Clinical Practice Guidelines for Surveillance Colonoscopy , 2011 .
so in compliance with the national guidelines . The guidelines for follow-up investigations after removal of polyps are outlined in table 3 .
Not all polyps are of equal significance . A tiny hyperplastic polyp in the rectum is almost certainly of no significance and does not require alteration of screening guidelines from those prior to the colonoscopy .
While a small adenomatous polyp should be managed in compliance with the guidelines , there are very high-risk polyps that may require tailored advice in relation to subsequent followup . For example , if a large sessile polyp with high-grade dysplasia is removed , it may be clinically appropriate to repeat colonoscopy earlier than the suggested guidelines — sometimes in a shortened interval of 6-12 months . This is to ensure the high-risk polyp has been completely removed and has not reoccurred . As always , while recommendations from national guidelines are important , advice needs to be tailored to the individual needs of the patient .
Polyps can generally be removed colonoscopically . Traditional techniques of polypectomy , including use of hot biopsy forceps and electrocautery snare , have now been augmented by more advanced techniques , such as endoscopic mucosal resection .
With newer techniques of colonoscopic polypectomy , most polyps can be removed without resorting to abdominal surgery . However , in a small number of patients , complete colonoscopic removal is not possible and some high-grade dysplastic polyps with involved margins may mandate segmental colorectal resection .
Further investigations While most colorectal cancers in Australia are diagnosed at colonoscopy , there may be circumstances in which other investigations may be indicated .
CT colonography CT colonography is not recognised in Australia as a communityscreening tool for colorectal cancer for the following reasons : first , it has not been shown to be more accurate than conventional colonoscopy ; second , it has no direct therapeutic value or the capacity to biopsy ; third , it still requires bowel preparation ; and finally , it carries a small risk of perforation and complications .
It may , however , be of value in patients in whom complete colonoscopy with caecal intubation cannot be accomplished . This may occur in 2-10 % of patients undergoing colonoscopy , depending on their circumstances .
Barium enema Despite now being regarded as an ‘ old ’ investigation , barium enema still has value in a small number of patients , particularly if colonoscopy is not readily available or CT colonography is deemed inappropriate .
It will occasionally add additional information regarding the obstructive nature of strictures or lesions .
Other investigations Occasionally , colorectal cancer will be incidentally diagnosed on investigations performed for other reasons — such as CT abdomen and pelvis , PET or ultrasonography — but these are not first-line diagnostic investigations .
20 | Australian Doctor | 2 June 2017