Organ transplant recipients with Merkel cell carcinoma have reduced progression-free, overall, and disease-specific survival independent of stage at presentation.

Abstract

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine carcinoma of the skin. Immunosuppression is associated with increased incidence of MCC. We sought to determine whether solid organ transplant recipients (SOTR) with MCC had decreased progression-free, disease-specific, and overall survival compared with immunocompetent patients. We conducted a retrospective cohort study examining 8 SOTR with MCC and 89 immunocompetent control subjects. Cox regression models were generated for outcomes of progression, disease-specific death, and death from any cause, adjusted for patient sex, age at diagnosis, and stage at presentation. SOTR had a 4.1-fold increased hazard for progression (95% confidence interval 1.57-10.95, P=.004), a 10.5-fold increased hazard for all-cause mortality (95% confidence interval 3.06-35.98, P<.0001), and an 11.9-fold increased hazard for MCC-specific death (95% confidence interval 2.67-53.08, P=.001), adjusted for sex, age, and stage at presentation. SOTR had decreased 1-year overall survival, 46.8% versus 88.6%, and decreased 1-year MCC-specific survival, 56.3% versus 95.2%. This is a single-center study from a tertiary academic care center, and may not be generalizable to all patient populations. SOTR have a significant reduction in overall, MCC-specific, and progression-free survival compared with immunocompetent patients. Further studies will determine whether aggressive treatment may improve outcomes in this high-risk population.