Exercise and pathologic complete response to cancer treatment: a systematic review and meta-analysis.
PURPOSE: Neoadjuvant chemotherapy (NACT) is a commonly recommended approach for treating several cancers, and improving patients' outcomes to this therapy is important. This systematic review and meta-analysis assessed the impact of exercise on pathologic complete response (pCR), a key short-term marker of treatment efficacy, in patients with solid tumors receiving NACT. METHODS: Four electronic databases were searched for randomized controlled trials with physical exercise during NACT as an intervention published until May 2025. Risk of bias was assessed using Cochrane RoB 2.0 and the TESTEX scale. A random-effect meta-analysis using the inverse variance method synthesized the results. Heterogeneity was assessed using I2 and chi2 statistics. Risk ratio estimated the effect size. RESULTS: Eight studies involving 504 patients with breast, esophageal, gastric, or rectal cancer were included in the final analysis. Exercise interventions consisted of aerobic and resistance exercise. Overall, there were no significant differences between exercise and control groups in the rate of pCR to NACT (pooled risk ratio: 1.08 (95% CI: 0.82 to 1.43) Z = 0.56, p = 0.58). However, meta-regression data from breast cancer (BC) studies (4 studies, 367 participants) suggest exercise may be associated with enhanced tumor response to NACT in HR + /HER2- subtypes (regression coefficient: 0.83 (95% CI: -0.00 to 1.67), p = 0.05). CONCLUSION: Exercise during NACT did not improve pCR across cancer types. Exploratory meta-regression findings suggest a possible benefit of exercise in BC patients with the HR + /HER2- subtype. These results should be interpreted with caution due to the small number of studies and low certainty of the evidence.