Stage and anatomic site determine the prognosis of mucosal melanoma (MM), regardless of thickness and a patient’s race or ethnicity, according to a study published in the Journal of the American Academy of Dermatology.

Study researchers sought to assess the influence of race or ethnicity, sex, tumor stage, tumor thickness, and anatomic site on MM survival estimates. Data was collected from patients diagnosed with invasive melanoma in a regional cancer registry. Information such as sex, race, and ethnicity, and tumor thickness was obtained from patients’ medical records. Melanomas were categorized as cutaneous or mucosal. Breslow depth was determined, and anatomic site, histologic type, and thickness information were recorded.

Results for the study showed that 132,751 cases of melanoma were diagnosed and registered in the database between 1994 and 2015. Of these, 130,927 were cutaneous and 1824 were mucosal. Five-year survival estimates for MM were significantly lower (27.64%; 95% CI, 25.42-29.91) than for cutaneous melanomas (76.28%; 95% CI, 76.03-76.53).

Five-year survival estimates were lower for patients diagnosed with MM than for patients diagnosed with cutaneous melanoma, regardless of sex and race or ethnicity. However, women had better rates of survival for both types of melanoma. Tumor stage independently influenced survival, but tumor thickness did not predict survival for neoplasms of known depth.

The difference in survival rates for patients with MM was not significant across all races and ethnicities. Regardless of thickness, MM had lower survival estimates than cutaneous melanomas. Survival for cutaneous melanomas decreased as thickness increased, but thickness for MM provided less predictive value.

Five-year survival estimates for MM according to primary anatomic site were 37.41% for genitourinary, 27.85% for oral cavity, 23.77% for nasal and sinus, 20.94% for gastrointestinal, 16.68% for anorectal, and 13.57% for other sites.

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Limitations of the study included a lack of standardized staging for MM, which could have led to misclassification of the extent of spread for some melanomas. The authors conclude that MM continues to be an aggressive disease with a poor prognosis. Because of the poor prognosis of MM of all stages, clinicians are recommended to treat aggressively upon diagnosis. The authors also advocate for the development of specific treatments for MM.

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Reference

Altieri L, Eguchi M, Peng DH, Cockburn M. Predictors of mucosal melanoma survival in a population-based setting [published online October 5, 2018]. J Am Acad Dermatol. doi: 10.1016/j.jaad.2018.09.054