Mixed Acinar Neuroendocrine Carcinoma of the Pancreas: Comparative Population-Based Epidemiology of a Rare and Fatal Malignancy in The United States

SIMPLE SUMMARY: Mixed acinar neuroendocrine carcinoma of the pancreas (MANEC-P) is one of the rarest pancreatic carcinomas. Although MANEC-P is rare, it is associated with a bad prognosis. The distribution of this fatal cancer is unknown worldwide. Our contribution is expected to be a detailed understanding of the epidemiology of this cancer in the United States. Expected results from the proposed research include an estimation of the incidence, prevalence, and cancer-specific survival of patients diagnosed with MANEC-P from a population-based cancer registry. This study will be followed by multiple epidemiological studies on the distribution of this fatal cancer worldwide. These epidemiological benchmarks will be used to initiate a consortium to generate real-world evidence with a natural history study for risk identification and treatment optimization for MANEC-P. The long-term goal is to develop an up-to-date epidemiologic and multi-omics knowledge library to enhance the diagnostics and therapeutics options and improve survival among patients diagnosed with MANEC-P. ABSTRACT: Mixed acinar neuroendocrine carcinoma of the pancreas (MANEC-P) is an extremely rare malignancy with a poor prognosis. However, epidemiological estimates of MANEC-P remain unknown. This study aimed to estimate and compare the incidence, prevalence, and cancer-specific survival (CSS) of MANEC-P in the United States (US). Patients with MANEC-P were identified through the Surveillance, Epidemiology, and End Results (SEER) and National Program of Cancer Registries databases between 2000–2017. The primary outcomes included age-adjusted incidence rate, limited-duration prevalence, and CSS. A total of 630 patients were identified for the incidence analysis and 149 for the prevalence and CSS analyses. The MANEC-P incidence rate was 0.011 per 100,000 individuals, which was the lowest among pancreatic cancer histologic subtypes. The incidence rate was significantly higher in men and Black races and peaked at 75–79 years of age. The incidence rate was the lowest in the midwestern region (0.009) and the highest in the northeastern US (0.013). The 17-year prevalence was 0.00005%, indicating that 189 patients were alive in the United States at the beginning of 2018. The median CSS of MANEC-P was estimated to be 41 (23, 69) months. In conclusion, MANEC-P is very rare, and its incidence rate has been steady in the US over the last two decades. MANEC-P has a poor prognosis and is the 5th leading cause of pancreatic cancer-related death in the US.