Impact of body mass index on the clinical outcomes of patients with HER2-positive metastatic breast cancer

Samuel Martel, Elena Poletto, Arlindo R Ferreira, Matteo Lambertini, Federico Sottotetti, Ilaria Bertolini, Filippo Montemurro, Antonio Bernardo, Emanuela Risi, Elisa Zanardi, Serena Ziliani, Silvia Mura, Chiara Dellepiane, Lucia Del Mastro, Alessandro Marco Minisini, Fabio Puglisi

Research output: Contribution to journalArticlepeer-review


BACKGROUND: Overweight and obesity are associated with an increased risk of developing many types of cancer, including breast cancer. Moreover, increased body mass index (BMI) seems to be associated with a worse prognosis in patients with HER2-positive early breast cancer. However, little is known about the impact of BMI on the clinical outcomes of HER2-positive metastatic breast cancer (MBC).

METHODS: This was a multicenter retrospective cohort study including 329 consecutive patients with HER2-positive MBC treated with first-line trastuzumab-based regimens. BMI at the time of MBC diagnosis was collected. World Health Organization BMI categories were used: underweight <18.5, normal 18.5-24.9 Kg/m2, overweight 25-29.9 Kg/m2, and obese ≥30 Kg/m2. The analyses were conducted using two categories: BMI < 25.0 (normal/underweight) and BMI ≥ 25 (overweight/obese). Progression-free survival (PFS) and overall survival (OS) rates were estimated using Kaplan-Meier method. Univariate and multivariate survival analyses were performed using the Cox's proportional hazards model. Disease response to therapy was analyzed using univariate and multivariate logistic regression.

RESULTS: Overall, 176 (53.5%) patients were normal/underweight and 153 (46.5%) overweight/obese. Median PFS was 14.8 months in BMI < 25 group and 15.7 months in BMI ≥ 25 group (adjusted-HR 0.88; 95% CI 0.66-1.17; p = 0.387). Median OS was 58.6 months in BMI < 25 group and 52.6 in BMI ≥ 25 group (adjusted-HR 0.88; 95% CI 0.59-1.31; p = 0.525). Overall response rate was 71.7% and 65.9% (p = 0.296) and clinical benefit rate was 82.1% and 83.3% (p = 0.781) in BMI < 25 and BMI ≥ 25 groups, respectively.

CONCLUSIONS: BMI does not seem to be associated with clinical outcomes in HER2-positive MBC patients.

Original languageEnglish
Pages (from-to)142-147
Number of pages6
Publication statusPublished - Feb 2018


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