Weight-Loss Surgery Reduces Cancer Risk in Women, Not Men

Weight-loss surgery, such as stomach stapling, could reduce cancer risk in obese women - but not men - according to new research.

It is widely known that obesity increases the risk of many types of cancer, but it was unclear whether surgery would cut the risk of cancer.

A Swedish study has found that female patients who had surgery were 42 per cent less likely to develop cancer. But there was no change to the incidence of cancer in men.

Scientists looked at a group of just over 2,000 Swedish patients who underwent operations to reduce their weight were monitored for an average of just over a decade as well as a similar sized group of obese patients who received standard treatment such as nutritional advice.

But researchers said they found no link between the lowered incidence of cancer and the patients' weight loss or reduced calorie intake.

They say that more research was needed to pinpoint exactly how the surgery acts to reduce a patient's cancer risk.

The authors, based at Sahlgrenska University Hospital in Gothenburg, concluded: 'In our study, the significant reduction in overall cancer incidence in the female surgery group emanated from a variety of cancer types, indicating a broad effect of bariatric surgery.'

Dr Andrew Renehan, of the University of Manchester's School of Cancer, said the findings reinforced the importance of studying the sexes separately.

He said the most likely explanation for the weight-loss surgery in reducing cancer risk was its impact on hormones.

Several common cancers are linked to the female sex hormone oestrogen.

"For women, the greatest cancer-prevention effects from weight reduction are likely to be for post-menopausal breast and endometrial cancers, two hormone-sensitive malignancies, the effects of which might manifest within a decade," Dr Renehan said. "By contrast, the effects of weight reversal might take much longer to become apparent for other obesity-related cancers, such as colon, rectal, and kidney cancers, which are numerically more common in men."

Dr Ian Campbell, medical director of the charity Weight Concern, said there was another reason why weight-loss surgery does not help men in the same way.

"In men, obesity is often goes hand in hand with a nutrient-poor diet, and lack of exercise and so even when weight loss has been achieved through surgery, unless these lifestyle issues are addressed, significant increased risk of some cancers will remain," he said.

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