While older and overweight women reportedly had more functional limitations than other women, the impact on survival was not statistically significant.
However, outcomes differed according to disease stage: physical limitation had a stronger effect on survival among women with localized disease than among those with advanced-stage disease. Although this seems counter-intuitive, it may reflect the finding that women with functional limitations have poorer treatment tolerance because they are more likely to be older, less physically active, and overweight or obese.
The results make "biological and clinical sense," according to the authors, because the functional limitations that affect survival "may reflect chronic inflammation and commensurately diminished function of vital organs or systems."
A limitation of the study is the lack of a control group of women without breast cancer, so the researchers could not determine whether the increase in mortality due to functional limitations was higher in women with breast cancer than in their counterparts without the disease.
In an accompanying editorial, Harvey Jay Cohen, M.D., of the Center for the Study of Aging and Human Development at Duke University, writes that the study's conclusions could be incorporated into cancer survivorship plans, especially for elderly survivors. Since "the main impact of functional limitations is on non-cancer causes of death," Cohen writes, "Such an evaluation could guide therapy regarding underlying co-morbidities and other reasons for functional decline, such as obesity and decreased physical activity."
Cohen also writes that the study importantly "suggests that implementing known interventions such as disease screening, chronic disease management, and diet and exercise programs for cancer survivors can have substantial impact."
|Contact: Kristine Crane|
Journal of the National Cancer Institute