Greater Risk of Melanoma and Non-Epithelial Skin Cancer After Primary Merkel Cell Carcinoma

Ugwu N, Cheraghlou S, Weiss J. Primary Merkel cell carcinoma is associated with increased, extended risk of subsequent melanoma and nonepithelial skin cancer. J Am Acad Dermatol. 2023 Nov;89(5):1060-1061. doi: 10.1016/j.jaad.2023.07.007. Epub 2023 Jul 13. PMID: 37451621.

Using data from 17 cancer registries in the SEER database from 2000-2019, the authors found 9,973 cases of histologically confirmed Merkel Cell Carcinoma. Patients within this group were found to be 2.28 times more likely to be diagnosed with a melanoma and 26.65 times more likely to develop a non-epithelial skin cancer than the general population.

Clinical Pearls

• This database analysis aimed to characterize the risk of subsequent skin cancers in Merkel Cell Carcinoma patients using the Surveillance, Epidemiology, and End Results (SEER) database.

• Using data from 17 cancer registries in the SEER database from 2000-2019, the authors found 9,973 cases of histologically confirmed Merkel Cell Carcinoma. Patients within this group were found to be 2.28 times more likely to be diagnosed with a melanoma and 26.65 times more likely to develop a non-epithelial skin cancer than the general population.

Discussion:

A recent study published by Ugwu et al. in the Journal of the American Academy of Dermatology provides new data on risks for future skin cancers in patients diagnosed with primary Merkel Cell Carcinoma (MCC). The authors noted how the incidence of MCC is increasing in the United States and is known to recur or metastasize often, providing a rationale for this study.

Using the Surveillance, Epidemiology, and End Results (SEER) database, the authors examined data from 17 cancer registries between 2000 to 2019. The authors used ICD codes to identify cases of MCC and subsequently searched for any patients who developed melanoma or a non-epithelial skin cancer (NESC) following diagnosis of MCC. Of note, the authors included the following tumors within the NESC definition: sebaceous gland tumors, sweat gland tumors, dermatofibrosarcoma protuberans, and Kaposi Sarcoma.

The authors identified 9,973 cases of MCC, of which 73 (0.7%) developed melanoma following diagnosis and 105 (1.1%) developed a NESC. When compared to the general population, MCC patients were 2.28 times more likely to develop a melanoma and 26.65 times more likely to develop a NESC. Interestingly, men had an increased likelihood to develop melanoma for more than 10 years following diagnosis of MCC. This study’s results suggest following initial diagnosis of MCC, dermatologists may need to consider additional long-term skin cancer screening for cutaneous malignancies which are not MCC.