21 Body Mass Index and Its Association With Pathological Response in Breast Cancer Patients in Venezuela

Background

The association of body mass index (BMI) with complete pathological response (pCR) and survival in the context of patients with breast cancer receiving neoadjuvant chemotherapy (NACT) isn’t sufficiently conclusive. Some studies reveal an association of increased BMI with lower pCR rates after NACT, while others do not. This study objective was to evaluate the relationship between a modifiable factor such as BMI and pCR in patients who received NACT and its relationship with survival.

Materials and Methods

Descriptive, retrospective, longitudinal study with 391 patients who received NACT, surgery, and radiotherapy at the Hospital Oncology Service (SOH-IVSS) during a period from 2011 to 2020.

Results

A total of 391 patients met the inclusion criteria. The mean BMI was 27.60 kg/m2, while 29.66% of patients had a BMI greater than or equal to 30 kg/m2 (obesity). Also, 68.1% of patients with obesity were postmenopausal (P = .004). The univariate analysis between BMI and the pCR rate was higher in patients with normal weight (31.6%) compared with patients who were overweight (15.8%) and obese (14.7%) (P ≤.001). Stage IIIB was the most prevalent, with 39.7% in the normal BMI group, 49.6% in the overweight group, and 57.8% in the obese group (P = .035). The overall survival (OS) at 120 months according to each BMI group was 100% for normal and 83.5% for the obese group. The log rank test revealed a statistically significant difference (P =.002). The risk of death in patients with normal BMI is significantly lower than in patients with overweight and obesity (HR, 0.57), indicating a lower probability of adverse events for this group. Disease-free survival at 120 months was 69% for the normal BMI group, 72% for the overweight group, and 79% for the obese group (P =.002; HR, 0.60). When evaluating OS according to BMI in patients with pCR, the OS at 120 months was 100% for patients with normal BMI and 82% for obese patients (P =.028). Patients with normal BMI have a higher probability of survival, even when a pCR is not achieved (P =.023).

Conclusion

BMI in our review was a relevant clinical factor, predictive of pCR in patients with breast cancer, affecting OS, suggesting that obesity may be related to worse long-term outcomes, even in patients with pCR. BMI can be considered another factor that influences the tumor microenvironment and the response to chemotherapy, which will allow us, through the identification of modifiable factors, to establish personalized treatment guidelines, strengthening therapeutic strategies and improving the prognosis of the disease. It is necessary to design new studies along this line of research.