C. Harrell Shreckengost1, C. R. Farley1, C. Zhang2, K. A. Delman1, R. R. Kudchadkar3, M. C. Lowe1 1Emory University School Of Medicine,Surgical Oncology,Atlanta, GA, USA 2Winship Cancer Institute,Biostatistics/Bioinformatics,Atlanta, GA, USA 3Emory University School Of Medicine,Hematology/Oncology,Atlanta, GA, USA
Introduction: Obesity is associated with adverse outcomes in multiple malignancies, but its impact in melanoma is poorly understood. Interestingly, recent data indicate protective effects of obesity on survival in systemically-treated metastatic melanoma. To evaluate whether these effects are intrinsic to the tumor or primarily treatment-related, we sought to examine the impact of obesity on clinical outcomes in clinically non-metastatic melanoma patients. As surgery is the definitive treatment for these patients, an improved understanding of the effects of obesity in early-stage melanoma could potentially aid in surgical decision-making.
Methods: Adults presenting to Emory University Healthcare between 2010-2017 with clinically non-metastatic cutaneous melanoma and known stage, height, and weight at the time of presentation were identified. The relationship between body-mass-index (BMI) and clinicopathologic characteristics was assessed.
Results: Of 1902 patients examined, 630 were obese (33.1%; BMI≥30), 708 were overweight (37.2%, BMI≥25 & <30), and 564 were normal-weight (29.7%, BMI<25). Demographics associated with obesity included male sex (OR=2.7, 95%CI=2.1-3.4, p<0.001) and lower income (OR=1.5, 95%CI=1.2-1.9, p<0.001). Melanomas in obese patients were thicker (2.0 mm±0.2) than in overweight (1.7 mm±0.1) or normal-weight patients (1.4 mm±0.1; p=0.002) at time of presentation. Melanomas of obese patients were also less likely to harbor BRAF mutations (OR=0.4, 95%CI=0.1-1.0, p=0.049). Ulceration, mitoses, and sentinel lymph node (SLN) status were not affected by obesity. In multivariate analysis, obesity independently predicted increased odds of presenting at Stage II (vs. Stage 0 or I; OR=2.1, 95%CI=1.5-3.1, p<0.001), but not at Stage III (p>0.05). At 33 months median follow-up, obesity was not an independent predictor of stage-specific survival (p>0.05).
Conclusion: Obese patients are twice as likely as their normal-weight peers to present with thicker melanomas, but they have similar stage-specific survival and SLN positivity. Despite providing a survival advantage in the response to systemic therapy at a later stage, obesity may promote more advanced clinicopathologic characteristics in early-stage melanoma. However, nodal status in clinically non-metastatic melanoma is not impacted by obesity and SLN biopsy should continue to be performed appropriately.