Screening method not effective for older women

A paper published recently in BMJ shows no effect of sigmoidoscopy screening in women aged 60 years and older. This new finding will have implications for a future Norwegian colorectal cancer screening program, where sigmoidoscopy is one of the recommended screening methods.

The large bowel inside the frame is examined during a sigmoidoscopy. Illustration: Blausen.com staff. "Blausen gallery 2014", Creative Commons.

PI Michael Bretthauer’s Clinical Effectiveness Group has published the paper Effectiveness of flexible sigmoidoscopy screening in men and women and different age groups: pooled analysis of randomised trials in BMJ. Authors are Øyvind Holme, Robert E. Schoen, Carlo Senore, Nereo Segnan, Geir Hoff, Magnus Løberg, Michael Bretthauer, Hans-Olov Adami and Mette Kalager.

Sex and age matter

The aim of the study was to compare the effectiveness of sigmoidoscopy in screening for colorectal cancer by patient sex and age. Data from three large scale randomised trials showed a difference in the effect of screening between the sexes; sigmoidoscopy screening reduces incidence of colorectal cancer in men, and in women younger than 60. In women aged 60 and over, incidence of colorectal cancer was not reduced by screening, possibly because of increased prevalence of cancers in the proximal colon in older women. The proximal colon is not examined during sigmoidoscopy.

Based on these findings, alternative screening methods should be considered for older women, says first author Øyvind Holme.

Screening in Norway

The National council for priority setting in health care has decided to recommend the Norwegian government to initialize a national screening program for colorectal cancer. One of the three proposed methods to include in the program is sigmoidoscopy. The study’s new findings suggest that other screening methods that more effectively detect proximal tumours should be considered in older women.