Effects of exercise during adjuvant chemotherapy on breast cancer outcomes.
Level 2 - randomized trial
Individual randomized controlled trial (exploratory survival follow-up)
PubMed 24633595 · doi:10.1249/MSS.0000000000000297
What was done
Exploratory long-term follow-up of the Canadian multicenter Supervised Trial of Aerobic versus Resistance Training (START). Between 2003 and 2005, 242 breast cancer patients receiving adjuvant chemotherapy were randomized to usual care (n = 82), supervised aerobic exercise (n = 78), or supervised resistance exercise (n = 82). The two exercise arms were combined for analysis (n = 160) and compared with usual care over a median follow-up of 89 months. The primary endpoint for this exploratory analysis was disease-free survival (DFS); secondary endpoints were overall survival, distant DFS, and recurrence-free interval.
What was found
Disease-free survival events occurred in 15.6% (25/160) of the combined exercise group versus 22.0% (18/82) of the usual care group. Eight-year DFS was 82.7% for exercise versus 75.6% for usual care (HR 0.68; 95% CI 0.37-1.24; log-rank P = 0.21). Secondary outcomes showed similar nonsignificant trends: overall survival HR was 0.60 (95% CI 0.27-1.33; P = 0.21), distant DFS HR was 0.62 (95% CI 0.32-1.19; P = 0.15), and recurrence-free interval HR was 0.58 (95% CI 0.30-1.11; P = 0.095). Subgroups showing potentially stronger DFS effects included patients with HER2-positive tumors (HR 0.21; 95% CI 0.04-1.02) and those completing 85% or more of planned chemotherapy (HR 0.50; 95% CI 0.25-1.01).
Why it matters
This study provides early randomized trial follow-up data evaluating whether exercise during adjuvant chemotherapy improves survival outcomes in breast cancer, establishing a basis for definitive phase III trials.
Limits
The trial was not originally powered for clinical survival outcomes, resulting in small event numbers and wide confidence intervals that cross 1.0 for all primary and secondary endpoints. Aerobic and resistance exercise arms had to be pooled for analysis, precluding assessment of modality-specific effects.
Cited by
- supports A study found that breast cancer patients who exercised during chemotherapy had a lower risk of recurrence or dying from breast cancer eight years later.