Purpose: Cancer treatments frequently reduce functional capacity and quality of life. The 6 Minute Walk Test (6MWT) is a valid measure of cardiorespiratory function, yet exercise responses across cancer types remain unclear.

Methods: Following PRISMA guidelines (PROSPERO: CRD420261466339), we systematically searched PubMed, Scopus, and Web of Science (inception–February 2026) for RCTs evaluating structured exercise effects on 6MWT in cancer patients. Random effects meta analysis (REML) calculated SMD with 95% CIs. Subgroup analyses examined cancer type, exercise modality, intensity, and duration. Publication bias was assessed using Egger's/Begg's tests and trim and fill.

Results: Seventeen studies (1,636 participants) were included. Exercise significantly improved 6MWT (SMD = 0.65, 95% CI: 0.07–1.19, p = 0.02), with substantial heterogeneity (I² = 93.0%). Cancer type significantly moderated effects (Q = 61.25, p = 0.001); breast cancer showed the greatest improvement (SMD = 1.28, p = 0.012), while prostate (SMD = 0.10, p = 0.870) and pancreatic cancer (SMD = 1.09, p = 0.205) were non significant. Exercise type also moderated outcomes (p < 0.001), with resistance training showing the largest effect (SMD = 5.75, p = 0.001, based on one study). Intensity moderated effects, but no intensity level alone reached significance.

Conclusion: Exercise improves cardiorespiratory function in cancer patients, but benefits vary by cancer type. Breast cancer patients respond best; prostate and pancreatic cancers may require optimized protocols. Long term programs (>12 weeks) yield more predictable outcomes. Prescriptions should be individualized.