Regular Exercise Confers a Significant Survival Benefit Among Patients With Breast Cancer

Even meeting HHS’s minimum requirements for daily and weekly exercise reduced breast cancer recurrence and mortality among patients with high-risk disease undergoing chemotherapy. This benefit was even seen in patients who had not met these requirements before their diagnosis, according to research from Roswell Park Comprehensive Cancer Center in Buffalo, New York, published in Journal of the National Cancer Institute.

The patient population they investigated consisted of 1340 individuals currently enrolled in the Diet, Exercise, Lifestyles and Cancer Prognosis (DELCaP) study, a questionnaire distributed as part of a larger trial from SWOG. Their levels of physical activity, according to HHS’ Physical Activity Guidelines for Americans, and the resulting effects were measured at 4 time points:

1. Baseline (study enrollment)
2. Six months after enrollment
3. One year after enrollment
4. Two years after enrollment

Four levels of physical activity were also used to classify patients, according to weekly MET hours:

1. Inactive: no weekly recreational physical activity (RPA)
2. Low active: less than 8.3
3. Moderate active: 8.3 to 16.0
4. High active: more than 16.0

Overall, large reductions in disease recurrence and mortality were seen among the patients who met the RPA guidelines both before and in the year following enrollment. These hazard ratios (HRs) were 0.59 (95% CI, 0.42-0.82) and 0.51 (95% CI, 0.34-0.77), respectively. These numbers only got better at the 2-year mark, coming in at 0.45 (95% CI, 0.31-0.65) and 0.32 (95% CI, 0.19-0.52).

When looking at amounts of RPA each week, the patients classified as low active (HR, 0.41; 95% CI, 0.24-0.68), moderate active (HR, 0.42; 95% CI, 0.23-0.76), and high active (HR, 0.31; 95% CI, 0.18-0.53) saw the most gains in mortality improvement.

Overall, the most patients (75.1%) were active at the 2-year mark. In addition, any level of consistent RPA throughout the study translated to 19% and 22% drops in disease recurrence and mortality, respectively. Even larger statistically significant gains were seen following time-dependent analyses. The mortality rate fell by 63% among patients who exercised on a regular basis versus those who did not and by 60% if they met the minimum requirements for RPA.

“Taken collectively, these findings have important implications in the clinical oncology setting because they suggest that a cancer diagnosis may serve as an impetus for increasing physical activity in some patients, and among these patients, beginning an exercise program after treatment resulted in a survival advantage,” stated Rikki Cannioto, PhD, ED, assistant professor of oncology, Department of Cancer Prevention and Control, Roswell. “These observations coincide with previous findings from our group showing that lower levels of regular, weekly activity were associated with a significant survival advantage.”

Due to the self-reported nature of the study, the study authors express caution about the possibility of recall errors on the part of the patients, which could mean data misclassification and skewed results.

Reference

Cannioto RA, Hutson A, Dighe S, et al. Physical activity before, during and after chemotherapy for high-risk breast cancer: relationships with survival [published online April 2, 2020]. J Natl Cancer Inst. doi: 10.1093/jnci/djaa046.