Basic physical limitations following breast cancer treatment can have far-reaching consequences that substantially affect how long a patient lives, a new study has said.
According to the study, breast cancer survivors with functional limitations - an inability to perform normal daily activities - caused by the disease or its treatment are more likely to die because of overall poorer health.
The scientists found that survivors who reported physical limitations after breast cancer treatment have the same risk of dying from breast cancer as those without limitations but are more likely to die from other diseases.
In particular, investigators found that older women, as well as overweight breast cancer patients, were more likely to experience functional impairments for at least 18 months after treatment.
The research pointed to risk factors where, with simple modifications in habits that allow more physical activity, health might be greatly improved.
"Our study provides evidence of why it is important to develop interventions that improve physical function, to mitigate the adverse effects of physical limitations," said Dejana Braithwaite of UCSF's Helen Diller Family Comprehensive Cancer Center.
"Intervention strategies - on the part of the individual, the community and the health provider - should emphasize physically active lifestyles," said Braithwaite.
Braithwaite collaborated with researchers at the Kaiser Permanente Northern California, the University of Utah, the University of California and Brock University in Canada.
"When we talk about improving physical function, we are talking about improving a woman's ability to perform normal functions of everyday life, like walking around the block, getting up easily from a chair or carrying a heavy bag of groceries. These activities appear to make a difference in a woman's chance of survival after a breast cancer diagnosis," said Bette Caan at the Kaiser Permanente Division of Research.
Many patients struggle with physical limitations after treatment as many as 39 percent, according to the new findings - yet little attention has been paid to those limitations and related problems, particularly among older women.
To determine how physical limitations following initial breast cancer treatment affect mortality, the scientists studied 2,202 women in California and Utah with breast cancer, questioning them about endurance, strength, muscular range of motion, and small muscle dexterity following initial treatment such as chemotherapy, radiation therapy or hormone therapy.
The women were part of the Life After Cancer Epidemiology cohort, and were followed for up to 11 years after diagnosis.
Outcomes differed according to disease stage. Women with localized cancer had higher rates of non-breast cancer death due to functional limitations than those with more advanced disease.
In addition, women with functional limitations may have poorer treatment tolerance because they are more likely to be older, less physically active, and overweight or obese.
As a result, the authors speculate that women with good physical function who tolerated therapy well might be over-represented in the group with more advanced disease.
"There is increasing evidence that regular physical activity, as little as 30 minutes of moderate intensity walking each day, can reduce the risk of breast cancer recurrence," said study co-author Patricia Ganz of UCLA.
"Women with functional limitations are less likely to be able to maintain regular physical activity and would likely benefit from intervention to reduce their limitations and increase physical activity," said Ganz.
The findings were published online in the Journal of the National Cancer Institute.