Moderate exercise linked to lower death risk for breast cancer survivors

Nov. 17 (UPI) -- Even moderate physical activity is associated with a 60% lower risk of death among breast cancer survivors -- a mortality risk similar to more active survivors, a new study suggests.

Survivorship care plans "should consider incorporating physical activity because even moderate activity may be vital for extending survival, as well as health-related quality of life," the researchers, led by Kaiser Permanente Southern California, said in their research letter. It was published Thursday in JAMA Network Open.

While the protective effect of physical activity on the risk of developing breast cancer is known, its impact after breast cancer diagnosis remains controversial, the investigators said.

So the scientists set out to evaluate the association of physical activity -- "beyond essential daily functioning" -- with risk of all-cause mortality in breast cancer survivors.

The study involved 315 participants from a California health plan. All were postmenopausal breast cancer survivors who had received their initial diagnosis of early-stage breast cancer at least two years prior.

The women, who averaged six years of survivorship and 71 years of age, were diagnosed between 1996 and 2012; their baseline interviews for the study were conducted between 2013 and 2015.

They were followed up until their date of death or the study's end in April 2022. Over this period, 45 participants, or 14.3%, died due to any cause, five from breast cancer.

During the study, the participants were asked about their leisure time physical activity and fatigue using two questionnaires: the Godin-Shephard Leisure-Time Physical Activity Questionnaire and another tool gauging the severity of fatigue.

The activity questionnaire looked at exercise of at least 15 minutes duration over a typical 7-day period, giving a composite score that classified exercise patterns as active, moderately active or insufficiently active.

The study found that mortality rates were 12.9 deaths per 1,000 person-years for active participants, 13.4/1,000 person years for moderately active, and 32.9/1,000 person years for insufficiently active participants.

In the Godin questionnaire, strenuous exercise, described as "heart beats rapidly," lists, as examples, running, jogging, hockey, football, soccer, squash, basketball, cross- country skiing, judo, roller skating, vigorous swimming and vigorous long-distance bicycling.

Moderate exercise, described as "not exhausting," lists, as examples, fast walking, baseball, tennis, easy bicycling, volleyball, badminton, easy swimming, alpine skiing, popular and folk dancing.

The questionnaire's third category, mild/light exercise, described as "minimal effort," lists yoga, archery, fishing from river bank, bowling, horseshoes, golf, snow-mobiling and easy walking.

The investigators said their analysis adjusted for factors including the survivor's age at baseline, breast cancer stage, fatigue, years since cancer diagnosis, self-reported race and ethnicity, history of insomnia and depression and types of adjuvant cancer therapies, such as chemotherapy and radiation.

And they noted the new study's findings are similar to those of a 2020 study on physical activity before, during and after chemotherapy and breast cancer survival.

"Our findings have implications for patient counseling on the benefits of exercise with regard to cancer outcomes, and this protection persists even after considering cancer treatments in the analysis," the new paper concludes.