Treatment and outcomes of melanoma in Asia: Results from the National Cancer Centre Singapore

Abstract

Background: Acral melanoma (AM) and mucosal melanoma (MM) make up more than half of melanomas in Asia but comprise only 5% of cases in Caucasians, where cutaneous melanoma (CM) predominates. AM and MM are thought to be genetically and biologically distinct from CM. We report the characteristics and outcomes of melanoma patients from the National Cancer Centre Singapore.

Methods: Case records of 210 patients treated between 2002 and 2014 were reviewed.

Results: Median follow-up was 2.5 years. CM, AM and MM made up of 37.6%, 33.8% and 16.2% of cases, respectively, with 6.2% each having ocular melanoma and unknown primary. Caucasians made up 16.2% of patients, accounting for 36.7% of CM but only 2.8 of AM and 2.9% of MM. Patients with MM (2.9% stage I, 14.7% stage IV) presented with higher American Joint Committee on Cancer (AJCC) stage than those with AM (16.9% stage I, 5.6% stage IV) or CM (24.1% stage I, 8.9% stage IV) (P = 0.01). Median overall survival (OS) was 5.7 years for all patients, and 1.0 year for metastatic disease. Considering stage I-III disease, multivariable Cox regression analysis demonstrated age ≥60 years and higher stage to be independent adverse prognostic factors for RFS and OS. Sentinel lymph node biopsy, undertaken for 56 stage I-III patients (25 AM, 31 CM) did not influence outcome.

Conclusion: Our study reinforces the known unique clinicopathologic features of melanomas in Asians where AM and MM predominate. Age and stage remain the most critical prognostic factors across all subtypes.

Keywords: Asian; acral; melanoma; mucosal; outcomes; treatment.