Association between pre-diagnosis BMI, physical activity, pathologic complete response, and chemotherapy completion...

Physical activity and lower BMI have shown benefit for breast cancer survival, but the association between these factors, pathologic complete response (pCR), and chemotherapy completion is not clear. We evaluated whether BMI and physical activity are associated with pCR and chemotherapy completion during neoadjuvant breast cancer treatment.

We conducted a retrospective case-control study of women given neoadjuvant chemotherapy for stage I-III breast cancer between 2010 and 2016. A medical record review provided pCR, chemotherapy completion, and patient characteristics. A telephone survey assessed physical activity 1 year before diagnosis. Unconditional logistic regression models identified factors associated with pCR and chemotherapy completion.

In our cohort (n = 243), the average age was 52.9 years (SD 13.0) and mean BMI was 29.5 kg/m² (SD 7.0). Seventy-five (31%) patients had pCR and 168 (69%) had residual disease. Patients with pCR had lower mean BMI than those with residual disease (28.2 (SD) vs. 30.1 (SD), P = 0.04). Exercise was associated with completion of chemotherapy (OR 7.6, 95% CI 1.4-41.2, P = 0.02).

Pathologic complete response was associated with lower BMI; chemotherapy completion was associated with exercising at CDC-recommended levels prior to breast cancer diagnosis.