Bowel cancer – left or right side matters

8^th December 2011 -The outcomes of the Bowel Cancer Screening Programme in England after the first one million tests has found a higher than expected proportion of left sided bowel cancers.

The results suggest different strategies may be needed to pick up disease on both sides of the body, as right sided cancers are thought to be more aggressive and less likely to be picked up by screening.

Bowel Cancer Screening Programme

Bowel cancer screening is for people without symptoms. It aims to detect bowel cancer at an early stage when treatment is more likely to be effective.

Regular screening for bowel cancer is now recommended for men and women aged 60 to 69 in England, Wales and Northern Ireland, and for men and women aged 50 to 74 in Scotland. People who are at high risk of bowel cancer can get tested earlier and more often. By 2014 the screening service in England will be available automatically to everyone aged between 70 and 74 years.

First million

Analysis of the first one million test results, published in the BMJ journal, Gut, show that the Bowel Cancer Screening Programme in England is on track to cut bowel cancer deaths by its target of 16%.

The results also show a much higher proportion of cancers detected were left sided.

The authors base their findings on an analysis of the first 1.08 million faecal occult blood tests, returned by patients invited for the first round of bowel cancer screening in England.

In all, 2.5% of men and 1.5% of women (21,106 people in all) had an abnormal test result and 17,518  people attended for further investigation.

Men were more likely to have cancer and its immediate precursor (higher risk adenomas) than women.

Unexpected

Seven out of 10 cancers (71%) picked up by screening were early stage disease and as expected, right sided cancer was more common in women than in men.

However, left sided cancers were considerably more common than expected, based on figures drawn from cancer registries.

These figures indicated that around two thirds of bowel cancers (67%) picked up by the screening 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% that were right sided.

The authors point to research suggesting that right sided cancers are more aggressive and less likely to be picked up by screening. "Different screening strategies may be required to effectively screen for right-sided bowel cancer," they conclude.

Bowel Cancer UK

Deborah Alsina, CEO of Bowel Cancer UK, said in a press statement: "It is extremely good news that the screening programme is saving lives from bowel cancer. As a higher proportion of cancers are being found in the left side of the bowel than predicted, the roll out of flexible sigmoidoscopy screening in the new year will help to save even more lives. However this does need to be rolled out quickly with a sustained focus on areas with low uptake of screening. Of course, early diagnosis is key to overcoming bowel cancer and we actively encourage everyone eligible to take part in screening, as this will give them the best chance of surviving the disease."

The NHS is introducing flexible sigmoidoscopy (flexi-sig) screening for all men and women when they reach the age of 55.This follows a trial which found this screening was a safe and practical test which, when offered only once to the appropriate age group conferred a substantial and lasting benefit.

Flexible sigmoidoscopy is a one-off test, which aims to detect bowel polyps and cancers early before any symptoms develop.

This screening test is an addition to the existing Bowel Cancer Screening Programme. People aged over 55 will be able to request flexi-sig screening up to their 60th birthday. At 60, people will be offered the faecal occult blood test as now, whether or not they've had flexi-sig screening.

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 both the UK and Europe.

Survival from bowel cancer is still only around 50% in the UK, and significantly lower than in other comparable countries.