The Bowel Cancer Screening Programme in England is on course to cut bowel cancer deaths by 16%, according to a University of Nottingham-led study of the first 1m test results.
But the survey suggests that better screening techniques should be developed because bowel cancers on the right side of the body were less likely to be picked up than those on the left.
Bowel cancer kills 16,000 people every year in the UK and is second only to lung cancer as the leading cause of cancer death in the UK and Europe. Survival from the disease is still only around 50% and is significantly lower than in other comparable countries.
The findings of the report are based on an examination of the first 1m faecal occult blood tests returned by patients who took part in the first round of bowel cancer screening in England. The screening programme for people between the ages of 60 and 69 started in 2006. It involves three tests every two years and has since been extended to those over 70.
The analysis of the screening programme has just been published in the journal Gut. It shows that a higher than expected proportion of cancers detected were on the left side of the bowel.
Prof Richard Logan, from the University’s Division of Epidemiology, who led the study, said: “It’s not yet fully understood why cancers on the right-hand side were not showing up during screening. It’s possible that they grow faster, and progress to causing symptoms more rapidly and so be diagnosed conventionally, or that they were less likely to bleed and so trigger a positive screening test result.”
Prof Logan believes the current test should be replaced by the more efficient and more sensitive faecal immunochemical test. He said: “It will cost money to introduce it, and that money is not currently there.”
By October 2008 around 2m people had been invited to take part in the screening programme and around half had accepted; 2.5% of men and 1.5% of women (21,106 people) had an abnormal test result and 17,518 people were investigated further. Most underwent colonoscopy. Men were more likely to have bowel cancer and its precursor (higher-risk adenomas), than women. These were found in around one in eight (11.6%) and around four out of 10 (43%) men, respectively, compared with just under eight per cent and 29%, respectively, of the women. Seven out of 10 cancers (71%) picked up by the screen were early stage disease, and as expected, right sided cancer was more common in women than in men. But left-sided cancers were considerably more common than expected, based on figures drawn from cancer registries. These indicated that around two-thirds of bowel cancers (66%) picked up by the programme would be left-sided and around one in four (24%) would be right-sided. Instead, more than three out of four (77%) cancers detected by screening were left-sided, compared with 14% of right-sided.
Research suggests that right-sided cancers are more aggressive and less likely to be picked up by screening. The report concludes that different screening strategies may be required for right-sided bowel cancer.