SEATTLE -- A new study from the Fred Hutchinson Cancer Research Center found that breast cancer survivors exercise less over time even though doctors say physical activity could keep their cancer from coming back.
The Fred Hutch study, which followed 631 women from New Mexico, Los Angeles County and Western Washington over 10 years, found that prior to their breast cancer diagnosis, about a third of the women were meeting U.S. physical activity guidelines - 150 minutes per week of moderate exercise or at least 75 minutes per week of vigorous activity. Two years later exercise levels were about the same, and after five years the number of women meeting the guidelines increased to 39.5 percent.
Unfortunately, after 10 years the rate dropped to about 21 percent, with fewer than 8 percent meeting activity guidelines throughout the entire study.
Dr. Caitlin Mason, a corresponding author on the study, told KOMO Newsradio's Carleen Johnson the findings are concerning because breast cancer survivors are among those who could most benefit from regular exercise. Past studies have shown a strong association between physical activity and reduced mortality, extended survival and higher quality of life among breast cancer survivors.
"For survivors who are at greater risk of a second cancer, physical activity is a really good behavior they can adopt to try their best to lower that risk," Mason said.
The American Cancer Society recommends cancer survivors exercise for at least 30 minutes five times a week.
"For survivors who have not been previously active, we advise that they gradually work up to these recommendations," Mason said.
The Fred Hutch Survivorship Clinic currently promotes the YMCA's "Exercise and Thrive" program which offers free 90 minutes exercise classes exclusively for cancer survivors.
Mason said researchers aren't sure why breast cancer survivors are exercising less. She said she initially suspected age might be a factor in the decreased exercise but found that even younger women weren't staying active.
"We don't know whether it is something unique about the cancer survivor experience or what is happening in that five to 10 years after diagnosis," Mason said.
Janna Waldher, a 30-year-old breast cancer survivor from Seattle, said her oncologist encouraged her to exercise through cancer treatment and after. Just four months cancer-free, she now tries to exercise for at least 20 minutes each day.
But, Waldher said after having breast reconstruction surgery she sometimes struggles to do certain physical activities that are more painful, such as running.
"I don't exercise the way I did before cancer," she said. "I'm learning my new limitations."
Mason said further research is needed to determine how fatigue or pain from cancer treatment might affect breast cancer survivor's activity levels.