Prognostic significance of body mass index in patients with metastatic renal cell carcinoma receiving first-line therapies

Objectives: Higher body mass index (BMI) is reportedly associated with improved prognosis of patients with various cancers. However, it is unclear whether this phenomenon, also known as the obesity paradox, applies to metastatic renal cell carcinoma (mRCC). We aimed to determine the prognostic significance of BMI in patients with mRCC receiving first-line therapies.

Materials and methods: We retrospectively reviewed patients with mRCC receiving first-line immune checkpoint inhibitor (ICI)-based combination therapy or tyrosine kinase inhibitor monotherapy. Overall survival (OS) was defined as the time from systemic therapy initiation to death from any cause or last follow-up. Baseline patient characteristics were compared by Mann-Whitney U test or Fisher's exact test. OS curves were constructed by Kaplan-Meier estimates and were compared by log-rank test. Multivariable analysis was performed via Cox proportional-hazards regression.

Results: Of the 183 patients included, 130 (71 %) were overweight (≥22 and 18 kg/m² in men and women, respectively), and 63 (34 %) received ICI-based combination therapy. There was a significantly higher proportion of men in the overweight subgroup (87 % versus 64 %; P = 0.002). During the study period, 97 patients died, and median (95 % confidence interval) OS was 39.0 months (31.5-66.3 months) and 28.1 months (17.6-39.7 months) in overweight and normoweight patients, respectively (P = 0.015). On multivariable analysis, overweight was independently associated with longer OS (HR 0.57; P = 0.014). Subgroup analyses of patients receiving ICI-based combination therapy yielded similar results.

Conclusion: Overweight is associated with favorable outcomes in patients with mRCC receiving first-line therapies.