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Abstract

Primary cutaneous melanomas of the female breast (PCMFB) are rare, occur in mostly sun-protected skin, and classified using the AJCC cutaneous melanoma staging system. We performed a retrospective analysis of patients (pts) diagnosed with PCFMB to determine clinicopathological features that correlated with patient outcome. Combining cohorts from 2 institutions, we identified 137 pts (23 in-situ, 114 invasive). Most pts were white (98%) with a median age of 44 years(y) at diagnosis. In pts with invasive melanoma, superficial spreading type (80%) and pT1a-category (70%) were most frequent; median Breslow thickness (BT) was 0.5mm (range: 0.1-17.0mm); 8.8% were ulcerated; median mitotic rate (MR) was 0/mm2 (range: 0-41/mm2). With a median follow-up of 9.2y, 1, 3, 5, 10 disease-specific survival (DSS) rates were 97%, 93%, 91% and 88%, respectively; the median DSS was not reached. By Kaplan-Meier analyses, AJCC T-category correlated with DSS (p<0.0001). Twenty-one patients developed metastasis: 11 regional only; 10 regional and distant. Twenty-three pts died, of which 10 was due to progression of melanoma. Cox regression analyses revealed the following statistically significant pt and primary tumor parameter associations with DSS (p<0.05): univariate - age, ethnicity, BT, ulceration, MR, nodular type, satellitosis, lymphovascular, and perineural invasion; multivariable- age, ethnicity, ulceration, MR and satellitosis. Metastasis to various sites correlated significantly with shorter DSS: any (HR=50.31, p<0.001); regional lymph nodes (HR=33.78, p<0.001); sentinel lymph node (HR=9.07, p=0.01); and distant (HR=68.19, p<0.001). These exploratory analyses suggest that PCMFBs are similar to primary melanomas of other cutaneous sites. Further exploration using larger cohorts is warranted for