Association between primary site of melanoma and survival of United States adult patients

Abstract

Introduction: Malignant melanoma is a neoplasm of pigment-producing melanocytes. Although it is less common than other types of skin tumour, it contributes to a large percentage of skin tumour-related mortality. Worldwide, several studies have shown that there could be an association between primary site and survival; however, a large population-base study has not been carried out. Objectives: The aim of this study was to assess the relationship between primary site of melanoma and survival in a large US adult population. Materials and methods: We analysed 227509 US melanoma patients from the SEER (Surveillance, Epidemiology, and End Results Program Registry) from 1973 to 2011. We excluded duplicate cases. We compared the primary site and survival using Kaplan– Meier curves. Hazard ratios (HRs) were determined using unadjusted and adjusted Cox regression models. Results: In the unadjusted model, the primary anatomical site was significantly associated with survival. Melanoma patients who had an overlapping lesion of skin as the primary site (the tumour overlaps the boundaries of two or more adjacent anatomical sites) were 10 times more likely to die within 5 years of diagnosis than patients with non-overlapping lesions located on the head or neck [HR=10.7, 95% confidence interval (CI)=10.3 to 11.1]. After adjustment for age at diagnosis, sex, race, ethnicity and stage at diagnosis, patients with overlapping lesions of skin still had a lower chance of surviving more than 5 years compared with patients with non-overlapping head and neck lesions, followed by trunk (HR=3.5, 95% CI=3.3 to 3.6, and HR=1.2, 95% CI=1.2 to 1.3, respectively). Conclusions: Overlapping lesion of skin had the worst prognosis, followed by trunk lesions, while lesions located in the upper limbs and shoulders had better prognosis. Clinical correlation and timely diagnosis of primary melanoma sites might improve survival and prognosis in this population. Acknowledgements: We would like to thank Florida International University, Dr Suliman Aba Al-Khail, Dr Khalid Alqumaizi, Dr Juan Zevallos, Dr Fred Saleh, Pura Rodriguez and Grettel Castro for their support and help.