The Influence of Obesity on Melanoma and Sentinel Lymph Node Diagnosis: A Retrospective Monocentric Study in 1001 Patients

SIMPLE SUMMARY: The impact of obesity on melanoma has rarely been researched. Incidence of obesity is rapidly growing and melanoma is one of the most prevalent types of cancers worldwide. Several studies have shown that overweight and obese populations not only have a higher risk of developing melanoma but also tend to present with thicker melanomas at the time of diagnosis. Given that melanoma thickness is one of the main predictors of the melanoma prognosis, a worse prognosis in a patient with obesity would be expectable. However, this has not yet been demonstrated in the literature. Our study is the first to show that obese patients are twice more likely to present with lymph-node metastases. Lymph node metastases is the second most important prognosis predictor of melanoma. Our findings, therefore, raise important questions regarding the screening and treatment of obese patients with melanoma. ABSTRACT: (1) Background: While obesity is a known independent risk factor in the development of melanoma, there is no consensus on its influence on melanoma prognosis. (2) Methods: In a monocentric retrospective study, data was collected from patients who underwent sentinel lymph node (SLN) biopsy for stage IB-IIC melanoma between 2013 and 2018. Patients were divided into groups according to their body mass index (BMI). The association between BMI and melanoma features, as well as the risk factors for metastases in SLN were examined. (3) Results: Of the 1001 patients, 336 had normal weight (BMI < 25), 402 were overweight (BMI >= 25 and <30), 173 obese (BMI >= 30 and <35) and 90 extremely obese (BMI >= 35). Overweightness and obesity were associated with higher tumor thicknesses at time of diagnosis. Ulceration was not influenced by the patient’s weight. Metastases in sentinel lymph node was almost twice more likely in extremely obese patients than in normal weight patients. Independent risk factors for metastases in SLN in our study were tumor thickness, ulceration, and BMI > 35. (4) Conclusions: This is the first study to show higher metastases rates in high-BMI patients with melanoma, raising important questions regarding the screening and treatment of this specific patient population.