Scientists from the German Cancer Research Center said that some cases of breast cancer are actually avoidable and need not occur at all and that the woman herself can take steps to prevent breast cancer from developing.
"Fifty-eight thousand women in Germany are diagnosed with breast cancer each year," said Jenny Chang-Claude." Therefore, a key question is whether there are behavioral changes that might help to lower the disease risk. Our study aims to determine the percentage of cases where these avoidable risk factors are responsible."
Epidemiologists studied 6,386 controls together with 3,074 breast cancer patients whose cancer had been diagnosed after menopause. They found that 19.4 percent of post-menopausal breast cancer cases were caused by hormone replacement therapy (HRT) and 12.8 percent of cases by lack of physical exercise. Together, they determined that HRT and lack of exercise caused 29.8 percent of all post-menopausal breast cancers. When researchers looked at another group of women with hormone receptor positive tumors (tumors that respond to sex hormones) they found that the rate of potentially avoidable cancers rose to 37.9 percent.
Alcohol consumption and obesity were also looked at but were found to have less of an influence on the development of cancer than lack of exercise and HRT.
Unavoidable reasons why a woman might get breast cancer included having a family history of the disease, having an early onset of the first menstrual period and having a late onset of menopause--these factors accounted for 37.2 percent of the cases in the study.
"That means that two factors which each woman has in her own hands are responsible for a similar number of postmenopausal breast cancer cases as the non-modifiable factors," Karen Steindorf said. "If behavioral changes in these two areas could be brought about, almost 30 percent of breast cancers after menopause could be prevented." Therefore, the DKFZ researchers recommend that women to take more exercise and to refrain from hormone replacement therapy, unless it is absolutely necessary."
Source: Population attributable risk of invasive postmenopausal breast cancer and breast cancer subtypes for modifiable and non-modifiable risk factors. Benjamin B.E. Barnes, Karen Steindorf, Rebecca Hein, Dieter Flesch-Janys and Jenny Chang-Claude: Cancer Epidemiology 2010, DOI: 10. 1016/j.canep.2010.11.003
Joanna is a freelance health writer for The Mother magazine and Suite 101 with a column on infertility, http://infertility.suite101.com/. She is author of the book, 'Breast Milk: A Natural Immunisation,' and co-author of an educational resource on disabled parenting, in addition to running a charity for people damaged by vaccines or medical mistakes.