A primary tumor located at the trunk among patients with Merkel cell carcinoma (MCC) is associated with worse survival outcomes than for tumors at other locations, according to research presented at the American Academy of Dermatology’s 2022 Annual Meeting in Boston, Massachusetts.

The study authors used data from the National Cancer Database Participant User File to evaluate the prognostic use of tumor location in patients with MCC.

The retrospective cohort study assessed cases of MCC that were diagnosed from 2004 to 2017. A total of 14,628 patients with a histopathology-confirmed diagnosis of MCC were included in the analysis.


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The participants were grouped according to primary tumor location—head/neck (44.9%), upper extremity (27.2%), lower extremity (16.9%), and trunk (11%)—as well as by American Joint Committee on Cancer 7th edition stage at diagnosis (stages I-IV).

Among patients with a primary tumor location at the trunk, 37.8% had stage III disease, and 10.4% had stage IV disease. In patients with an upper extremity primary location, 28.1% had stage III disease, and 3.9% had stage IV disease. Among patients with a lower extremity primary location, 35.9% had stage III disease, and 6.6% had stage IV disease. In patients with a head/neck primary location, 27.5% had stage III disease, and 5.8% had stage IV disease.

Wide local excisions were used less frequently in the head/neck region (43.9%) compared with the trunk (52.7%), upper extremity (56.6%), and lower extremity (52.6%). Excisions with margins 2 cm or greater (120.1 months) were not associated with a survival benefit vs excisions with a margin 1 cm or greater (117.3 months) in any tumor location.

Primary tumor location at the trunk was associated with the worst survival outcomes among the 4 locations (median overall survival, 36.1 months), compared with head/neck (46.2 months), upper extremity (83.7 months), and lower extremity (69.6 months; P < .001).

“To our knowledge, this is the largest study investigating the prognostic utility of tumor location in cases of MCC,” stated the researchers. “The rising incidence of MCC cases has been attributed to an aging population and the increasing use of immunosuppressive therapies. Tumor location might be of clinical value when treating patients with MCC of the skin.”

Reference

Mazal S, Najmi M, Philipovskiy A, Konstantinidis I, Castro J. Merkel cell carcinoma. does location matter? Presented at: the American Academy of Dermatology (AAD) 2022 Annual Meeting; March 25-29, 2022. Poster 34178.