Effect of pretreatment central adiposity on the cardiometabolic risk of male germ cell tumor survivors after cisplatin-based chemotherapy.
Authors: Wibmer Andreas Georg , Feldman Darren R. , Chen Carol , Bromberg Maria , Dinh Paul C , Zheng Junting , Capanu Marinela , Travis Lois B. , Vargas Hebert Alberto 
Published: June 2021

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Background: Preferential fat accumulation in the visceral compartment (i.e. central adiposity) increases cardiovascular risk in the general population independent of body mass index (BMI). We investigated how body fat distribution modulates the cardiometabolic risk of male germ cell tumor (GCT) survivors after cisplatin-based chemotherapy. Methods: For 456 patients in The Platinum Study enrolled at Memorial Sloan Kettering Cancer Center, visceral (VAT) and subcutaneous (SAT) adipose tissue compartments were quantified on pre-chemotherapy computed tomography (CT) scans (median time between CT and chemotherapy: 13 days, range: 0-56). The VAT/SAT ratio was calculated as a quantitative indicator of central adiposity. Endpoints were (I) post-chemotherapy cardiovascular risk as per the office-based Framingham risk calculator, and (II) incidence of post-chemotherapy cardiometabolic disease defined as need for new anti-hypertensive drugs, or lipid-lowering drugs, or medication used to treat diabetes. Changes in fat distribution after chemotherapy were analyzed in a subgroup with post-chemotherapy CTs (n = 108; median interval from chemotherapy start: 18 months, range: 7-185). Linear regression with interaction terms (endpoint 1, subgroup analysis) and Cox proportional hazard regression (endpoint 2) were applied. Results: For all 456 patients, median age at chemotherapy initiation was 31 years and median follow-up was 27 months (range: 7, 207). At baseline (pre-chemotherapy), the median BMI was 26.2 kg/m2, and 102 patients (22.4%) had a BMI of ≥30 kg/m2. The median VAT/SAT ratio at baseline CT was 0.49, and positively associated with higher post-chemotherapy Framingham risk scores after adjustment for age, BMI, and blood pressure measurements at chemotherapy start, as well as post-therapy follow-up time (adjusted β-estimate: 1.36, 95% CI: 1.15, 1.59, p < 0.001). A higher VAT/SAT ratio also inferred a higher likelihood of new onset cardiometabolic disease in patients with BMI ≥30 kg/m2 (age-adjusted HR: 3.11, 95%CI: 1.01, 9.62, p = 0.048), but not in those with BMI < 30 kg/m2. In the subgroup analysis, we observed a significant increase of BMI after chemotherapy (mean: +1.1 kg/m2, 95% CI: +0.58, +1.54; p < 0.001). Changes in BMI were positively associated with changes of the VAT/SAT ratio (β-estimate: 3.0, 95% CI: 2.23, 4.04; p < 0.001), meaning that weight gain occurred preferentially in the VAT compartment, while weight loss tended to be paralleled by an improved body fat distribution. Conclusions: In male GCT patients, central adiposity at baseline increases cardiometabolic risk after cisplatin-based chemotherapy, particularly for obese individuals. Quantification of an individual’s body fat distribution on pre-chemotherapy CT could potentially help to identify high risk individuals who may benefit from intensified risk-modulating interventions.