Weight loss limits the risk of Breast Cancer after Menopause

American researchers have looked at the proportion of breast cancers attributable to weight gain after menopause. They found that weight gain represents a risk but that, conversely, a slight weight loss allowed to reduce it.

With smoking, alcohol consumption and a sedentary lifestyle, being overweight is recognized as a risk factor for developing certain types of cancer. Better prevention is therefore an important health issue, to fight against cancer but also against other chronic diseases such as cardiovascular disease and diabetes.
In a recent study, researchers at the City of Hope National Medical Center say that this risk factor is very important during menopause. They point out that postmenopausal women who lost weight were at a lower risk of developing invasive breast cancer compared to those who gained a few pounds.

If it is established that overweight and obesity are associated with a risk of developing a dozen cancers including breast cancer after menopause, the researchers felt that studies to determine precisely if weight loss could reduce this risk in postmenopausal women have yielded mixed results. To examine the question, they analyzed data from 61,335 women who participated in an observational study, the World Health Initiative Observational Study, who did not have breast cancer and whose mammography examinations were normal. Their weight, height and body mass index (BMI) were assessed at the beginning of the study and again three years later.

A risk even if the weight gain is light

During an average follow-up of 11.4 years, 3,061 new cases of invasive breast cancer were diagnosed. The researchers found that women who lost 5% of their starting weight had a 12% lower risk of breast cancer than women whose weight remained stable according to their body mass index. Most importantly, about 5% weight gain was associated with a 54% higher incidence of triple negative breast cancer. It is a distinct type of breast cancer representing 15 to 20% of cases, which is characterized by a worse prognosis than other forms because generally more aggressive with a greater risk of recurrence.

"Our study indicates that a moderate to relatively short-term weight reduction was associated with a statistically significant reduction in breast cancer risk in postmenopausal women," says lead author of the study Dr. Rowan Chlebowski. These results echo those of a study published by Inserm in 2016 that suggests that more than half of the most commonly diagnosed breast cancer cases in post-menopausal women worldwide are attributable to behavioral: body mass index, alcohol consumption, diet or use of a hormonal treatment of menopause.

The National Cancer Institute also warns that after cancer, overweight increases the risk of developing recurrence or other cancer. To prevent this risk, it is recommended to practice every day at least 30 minutes of moderate intensity physical activity, to limit sedentary activities (computer, television ...), as well as foods with a high energy density: too rich in fats and / or sugars. "Both in terms of quantities consumed and frequency of consumption," says the Inca, which calls for focusing on energy-dense foods such as fruits and vegetables and monitoring its weight regularly, at least once a month.