Supervised exercise during neoadjuvant breast chemotherapy

Evidence label: No demonstrated tumor-response benefit · Clinical goal: improve tumor response and treatment tolerance during neoadjuvant chemotherapy

Evidence at a glance

Population: 102 people with breast cancer receiving 18–24 weeks of neoadjuvant chemotherapy.
Intervention: supervised high-intensity interval and progressive resistance training three times weekly.
Result: MRI tumor shrinkage and pathologic complete response were not improved; fitness and some treatment-delivery measures favored exercise.

What was studied

Neo-train randomized 50 participants to exercise and 52 to usual care. MRI tumor-size change was the primary outcome. Radiologic and pathologic complete response, chemotherapy delivery, admissions, fitness and patient-reported outcomes were secondary.

What the evidence shows

The median between-group difference in tumor-size change was −3.0 mm (95% CI −8.0 to 14.0). Radiologic complete response was 65% versus 56% (OR 1.16, 95% CI 0.39 to 3.91), and pathologic complete response 59% versus 56% (OR 1.03, 95% CI 0.43 to 2.46). Relative dose intensity, dose delays, hospital stay and fitness favored exercise, but these secondary findings do not convert a null tumor endpoint into cancer-control efficacy.

This is supportive-care or rehabilitation evidence. It does not show that the intervention treats cancer, prevents recurrence or prolongs survival unless a record explicitly identifies a validated cancer-control endpoint.

Limits and uncertainty

The trial was modest in size, could not exclude smaller subgroup effects and was not powered for recurrence or survival. Quality of life, distress and body composition did not differ. Multiple foundations funded the study; the primary report was open access.

Safety and practical context

High-intensity training during chemotherapy requires adjustment for blood counts, infection, cardiotoxic therapy, neuropathy, falls, bone health and day-to-day symptoms. Exercise is supportive care; it does not replace systemic treatment.

Questions for the care team

Is supervised interval and resistance training safe with my regimen and current blood counts?
Which outcome matters here—fitness and treatment tolerance, or tumor response?
How will the program change on fever, dizziness, neuropathy or severe fatigue days?

Sources

Literature searched: October 16, 2026 · Record appraised: October 16, 2026

Educational evidence summary, not personal medical advice. Research regimens describe what was studied; they are not personal prescribing instructions and should not replace cancer treatment or individualized supportive care.