Effects of exercise therapy on chemotherapy delivery and response in primary breast cancer: A secondary analysis of a randomized trial.
Level 2 - randomized trial
Secondary analysis of a randomized controlled trial
PubMed 39306704 · doi:10.1002/cncr.35575
What was done
This was a secondary analysis of a phase 2 randomized controlled trial comparing exercise therapy (n = 72) with usual care (n = 72) in patients with primary breast cancer. The intervention consisted of individualized treadmill walking three times weekly for 20 to 50 minutes per session at 55% to 100% of baseline capacity. Outcomes assessed were chemotherapy relative dose intensity (RDI), tolerability (blood laboratory values and patient-reported outcomes), and pathologic complete response (pCR; ypT0ypN0) among patients receiving neoadjuvant chemotherapy.
What was found
In the exercise group, 51 patients (71%) reached 100% RDI compared with 41 patients (57%) in usual care (p = .08). Rates of grade 3 or higher neutropenia and anemia were 22% versus 39% and 7% versus 10% in the exercise and usual care groups, respectively. In the subset receiving anthracyclines (n = 104), 41 (77%) achieved 100% RDI in the exercise group compared with 29 (57%) in the usual care group (p = .026). Among patients receiving neoadjuvant chemotherapy (n = 51 tumors), pCR rates were 27% (95% CI, 12%-50%) for exercise versus 28% (95% CI, 13%-47%) for usual care (p > .9).
Why it matters
Structured exercise therapy may help maintain full dose intensity during anthracycline-based chemotherapy for primary breast cancer without increasing high-grade hematologic toxicity. However, exercise did not translate to higher pathologic complete response rates in neoadjuvant settings.
Limits
As a secondary analysis, the study has a modest total sample size (n = 144) and is underpowered for subgroup analyses, including the neoadjuvant cohort (n = 51). The main overall dose intensity difference did not reach statistical significance (p = .08), and specific patient-reported outcome scores were not detailed 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.