Usage of immunotherapy in Merkel cell carcinoma from 2004 to 2016: A National Cancer Database (NCDB) analysis.

Abstract

e21576 Background: Merkel Cell Carcinoma (MCC) is a rare and aggressive skin malignancy with increasing incidence, likely due to an aging population. MCC has been shown to have an increased prevalence in immunosuppressed patients, and current clinical trials are investigating the potential for immunotherapy treatments. As the understanding of the underlying pathogenesis of MCC progresses, the ability to implement specific immunotherapy targets is being investigated and showing promise. Methods: Using the NCDB, we identified 6,918 patients diagnosed with Merkel Cell Carcinoma between 2004-2016 using ICD-O-3 histology code 8247. The cohort was analyzed to identify differences in survival outcomes among patients who received immunotherapy, chemotherapy, a combination of chemotherapy and immunotherapy, and neither chemotherapy nor immunotherapy. We performed univariate analysis to assess median length of survival for each of these specific treatment modality cohorts, in addition to descriptive statistics. Data were analyzed using SPSS and statistical significance was set at α = 0.05. Results: Between 2004 and 2016, 118 patients in the NCDB received immunotherapy. From 2004-14, 21 patients received immunotherapy (1.9 patients per year). The usage of immunotherapy increased drastically in 2015 and 2016 with 18 patients and 79 patients being treated with immunotherapy, respectively. Most immunotherapy patients (59%) received treatment at an academic research center while the remaining patients received immunotherapy at a comprehensive community cancer program (24.8%), an integrated cancer network (12%), or a community cancer program (4.3%). 41.7% of MCC immunotherapy patients were between 33 and 69 years of age, whereas 59.3% ranged from 70-90 years of age. Of the 118 MCC patients who received some form of immunotherapy, 39% had stage IV MCC, 38.1% had stage III MCC, 5.9% had stage II MCC, and 9.3% had stage I MCC. Conclusions: As the use of immunotherapy in MCC continues to rise, especially at academic research centers, future studies should investigate the trends of its usage, its effects on patient survival, and the stage of MCC in which immunotherapy is most often used. We found that patients that received both chemotherapy and immunotherapy had a significantly lower median survival than all other treatment combinations. We hypothesize that the poorer survival rates in the patients that received some form of immunotherapy is due to a later stage of treatment, but this will become clearer as the sample size of MCC patients receiving immunotherapy continues to grow.[Table: see text]