Bowel Cancer family history? Start screening earlier
The importance of family history as an indicator of future risk of colorectal (bowel) cancer has been highlighted by changes to the national guidelines from the prevention, early detection and management of the disease, according to the authors of a guideline summary published online today by the Medical Journal of Australia.
The guideline revision was led by Professor Mark Jenkins, of the University of Melbourne Centre for Cancer Research, and director of the Centre for Epidemiology and Biostatistics, School of Population and Global Health. Co-authors include Professor Alex Boussioutas and Professor Jon Emery, also of the Centre for Cancer Research.
The guidelines differ from the previous ones, published in 2005, in a number of ways, wrote the authors. The criteria for classification by family history into risk categories based on family history of colorectal cancer have shifted slightly based on new evidence, changing screening recommendations for some patients:
- Category 1 (at near average risk): people with no first-degree relatives with colorectal cancer -- immunochemical FOBT (iFOBT) every 2 years from age 50 to 74 years; people with one first-degree relative with colorectal cancer diagnosed at 55 years or older – biennial iFOBT from age 45 years should be considered;
- Category 2 (at moderately increased risk): people with one first-degree relative with colorectal cancer diagnosed with colorectal cancer at age 55 years or older – biennial iFOBT from age 40 to 49 years then colonoscopy every 5 years from age 50 to 74 years;
- Category 3 (high risk): people with three first-degree relatives with colorectal cancer – biennial iFOBT from age 35 to 44 years, then colonoscopy every 5 years from age 45 to 74 years.
“Given potential delays in transitioning to colonoscopy due to service availability, participation in the iFOBT screening offered by the National Bowel Cancer Screening should be recommended until colonoscopy can be arranged,” the authors wrote.
“The recommended age to stop screening is age 74, but for those with a family history of colorectal cancer the optimal age to stop screening is not known. Health economic research is needed to determine whether the benefits of iFOBT screening or colonoscopy screening beyond age 74 years outweigh the inherent risks.
“Health economic research within varying national cost contexts is needed to assess the cost-effectiveness of screening for various categories of family history, evaluate the screening strategies and further examine the relationship between risk and age.
“The 2017 guidelines recommend screening modality based on risk according to age and family history. Biennial iFOBT screening from age 50 is recommended for the majority of Australians, with modest or no family history, from age 50 years. The National Bowel Cancer Screening Program offers this screening to all Australians from age 50 to age 74 by mailing them a home test kit. This test detects cancer early, saves lives and is simple, clean, safe and done at home. Depending on the strength of the family history, it is recommended to start iFOBT screening from age 35 or 45 years (ie, up to 15 years younger) before transitioning to colonoscopy after 10 years,” they concluded.