Cisplatin-Based versus Carboplatin-Based Chemotherapy for Extrapulmonary Neuroendocrine Carcinomas: A Real-World Study

Objective: This study aimed to assess the survival differences between cisplatin/etoposide versus carboplatin/etoposide chemotherapy regimens in the management of patients with extrapulmonary neuroendocrine carcinomas (NECs). Methods: Administrative cancer care databases in the province of Alberta, Canada, were reviewed, and patients with extrapulmonary NECs (including those with small cell and large cell neuroendocrine carcinomas) who were treated with either cisplatin/etoposide or carboplatin/etoposide, 2004-2019, were reviewed. Kaplan-Meier survival estimates were used to compare the survival outcomes according to the type of platinum agent, and multivariable Cox regression analysis was used to assess the impact of the type of platinum agent on overall survival outcomes. Results: A total of 263 eligible patients were included in this analysis. These include 176 patients who received cisplatin/etoposide and 87 patients who received carboplatin/etoposide. Using Kaplan-Meier survival estimates, patients treated with cisplatin had better overall survival compared to patients treated with carboplatin (p = 0.005). Multivariable Cox regression analysis suggested that the following factors were associated with worse overall survival: higher Charlson comorbidity index (HR: 1.17; 95% CI: 1.05-1.30), gastrointestinal primary site (HR: 1.55; 95% CI: 1.12-2.14), stage IV disease (HR: 1.75; 95% CI: 1.28-2.38), and use of carboplatin (HR: 1.40; 95% CI: 1.02-1.92). Conclusions: The current study suggested that cisplatin/etoposide might be associated with better overall survival compared to carboplatin/etoposide among patients with extrapulmonary NECs. It is unclear if this is related to differences in inherent responsiveness to the 2 platinum agents or due to differences in comorbidity burden between the 2 treatment groups.