Overweight and Risk of Recurrence Following Neoadjuvant Chemotherapy in Breast Cancer.

Background: Having overweight is increasingly recognized as a risk factor for poor breast cancer (BC) outcomes. Previous studies have linked high body mass index (BMI) to an increased risk of recurrence and higher mortality. While most research has focused on patients treated with adjuvant chemotherapy, this study examines the impact of overweight on recurrence-free survival (RFS) in BC patients treated with neoadjuvant chemotherapy (NACT).

Materials And Methods: This study included 490 Swedish BC patients who completed NACT between 2005 and 2019. During a follow-up period averaging 5 years, 116 patients (24%) experienced recurrences at any location. The association between overweight (BMI ≥ 25 kg/m) at BC diagnosis and RFS was analysed using univariable and multivariable Cox regression models.

Results: The majority of patients (56%, 275/490) were classified as overweight. Patients with overweight tended to present with slightly more advanced disease stages and were more likely to have ER-/HER2- BC. Multivariable Cox regression analysis, adjusted for age and menopausal status, revealed that patients with overweight had a 47% higher hazard of recurrence compared to patients without overweight (hazard ratio [HR] 1.47, 95% CI 1.01-2.15). Subgroup analysis showed the largest relative effect in the ER+/HER2+ subgroup. Notably, the association between overweight and recurrence appeared independent of whether pathological complete response was achieved.

Conclusions: Overweight was associated with a higher risk of recurrence following NACT. Future research should explore whether BC prognosis can be improved by addressing modifiable factors that may mediate the impact of overweight on recurrence.