A quarter of women with breast cancer will die from cancer spreading around the body – exercise is the most important lifestyle factor in preventing this

150 minutes of moderate exercise is ideal Petri Artturi Asikainen/Getty

For women who have recovered from breast cancer, exercise appears to be the most important lifestyle choice to reduce the risk of death from a relapse.

Around a quarter of all women with breast cancer will eventually die when the cancer spreads to other parts of the body. But living more healthily can reduce the risk of this happening.

To find out what lifestyle changes might have the greatest benefit, Ellen Warner and Julie Hamer of Sunnybrook Health Sciences Centre in Toronto, Canada, analysed 67 studies that examined factors such as diet, exercise and weight, and their effect on the health of women who had been successfully treated for breast cancer.


They conclude that physical activity can reduce the chance of death from a breast cancer relapse by up to 40 per cent. “Exercise had the most consistent and greatest [impact] on the relative risk of breast cancer death,” says Warner. The ideal amount is 150 minutes of moderate physical activity spread over a week, she says.

It is hard to isolate why exercise confers such benefits, says Warner, but one possible explanation is that it suppresses inflammation that could otherwise damage cells and increase the risk of cancer spreading.

One potential problem with the study is that the women decided how much exercise to do, but those with undetected secondary cancers might have been too tired or in too much pain to exercise, skewing the apparent benefit of exercise on the death rate, says Anne McTiernan of the Fred Hutchinson Cancer Research Center in Seattle, Washington. “A randomised trial, with women assigned at random to an exercise or control group then followed over time, would be very helpful,” she says.

Warner says the second most important lifestyle factor is limiting weight gain after cancer treatment. Different types of diet appeared to have no effect on risk of relapse.

Journal reference: Canadian Medical Association Journal, DOI: 10.1503/cmaj.160464