A multicenter study headed by Melinda Irwin, M.D., from the Department of Epidemiology and Public Health at Yale School of Medicine, have found that women who are diagnosed with breast cancer are less active after the diagnosis leading to increase in body weight and body fat, which, in turn, leads to poorer breast cancer diagnosis. The population-based, multicenter study involved 856 patients with breast cancer. The researchers collected information on physical activity of the subjects before and after breast cancer diagnosis using a questionnaire. They then compared the levels of physical activity during the two periods to see if there was an association with the severity of disease, treatment type, age and body mass index.
On average, a woman's physical activity decreased by two hours a week after diagnosis. There was also indication that women who underwent intensive therapies such as surgery, radiation and chemotherapy had a 50% decrease in their physical activity as compared to only a 24-percent decline in patients treated with surgery alone. Those women who underwent radiation therapy had a 24-percent decline in physical activity. The study also found that those with higher body mass index had a 41 per cent decline in physical activity compared to 24 percent decline in women of normal body mass index. The researchers concluded that there is an increased risk of recurrence and reduced survival time for those women with increased body weight at the time of breast cancer diagnosis.