Effects of aerobic or resistance exercise during neoadjuvant chemotherapy on tumor response and therapy completion in women with breast cancer: The randomized controlled BENEFIT trial.
Level 2 - randomized trial
Randomized controlled trial
PubMed 40447136 · doi:10.1016/j.jshs.2025.101064
What was done
In the randomized controlled BENEFIT trial, 180 women with breast cancer scheduled for neoadjuvant chemotherapy (NACT) were randomly assigned to supervised resistance training (RT, n = 60), supervised aerobic training (AT, n = 60) twice weekly during NACT, or a waitlist control group (WCG, n = 60). The primary outcome was change in tumor size (categorized due to skewed distribution). Secondary clinical outcomes derived from medical records included pathologic complete response (pCR), type of surgery, axillary lymph node dissection (ALND), premature discontinuation of chemotherapy, and relative dose intensity (RDI). Multiple (ordinal) logistic regression analyses were conducted.
What was found
There was no significant difference in post-intervention tumor size between RT or AT and WCG overall. A significant effect modification was observed by hormone receptor (HR) status (p interaction = 0.030). In HR+ tumors, AT showed trends toward improved tumor shrinkage (OR = 2.37, 95% CI: 0.97–5.78), pCR (OR = 3.21, 95% CI: 0.97–10.61), and ALND (OR = 3.76, 95% CI: 0.78–18.06) compared with WCG, with slightly less pronounced effects for RT. In HR- tumors, AT significantly improved RDI (OR = 3.71, 95% CI: 1.20–11.50), as did RT (OR = 2.58, 95% CI: 0.88–7.59). Across all participants, both exercise groups demonstrated significantly reduced premature discontinuation of chemotherapy compared with control (OR [no vs. yes] = 2.34, 95% CI: 1.10–5.06).
Why it matters
This study provides randomized trial evidence that exercise during neoadjuvant chemotherapy aids treatment adherence and completion, while offering preliminary clinical evidence that exercise may enhance tumor response in specific breast cancer subtypes.
Limits
The primary outcome was null in the overall population. Subgroup findings by hormone receptor status were derived from small subsets resulting in wide confidence intervals crossing or near the null. Skewed tumor size data necessitated categorization, which may reduce measurement granularity. Long-term recurrence and survival outcomes were not assessed in the abstract.
Cited by
- supports Studies show cancer patients who exercise during chemotherapy complete more of their chemotherapy with fewer dose reductions and delays.