Objective:
Gallbladder adenocarcinoma and neuroendocrine neoplasms are two distinct histologic subtypes whose incidence and behavior are suspected to vary considerably. This retrospective study aims to report the differences in presentation and behavior of adenocarcinoma and neuroendocrine histologic subtypes within the United States population.
Methods:
We performed a retrospective study of the National Cancer Database (NCDB) from 2011 to 2020 comparing adenocarcinoma and neuroendocrine histologic subtypes. Adenocarcinoma and neuroendocrine subtypes were grouped and then chi-square tests and post hoc analyses using SPSS were performed to evaluate whether there were significant differences in the incidence of each group across selected variables. Histologic subtypes that were not adenocarcinoma or neuroendocrine subtypes, including patients with indeterminate or omitted histologic data, were excluded from the analyses.
Results:
A total of 30788 patients were identified with gallbladder neoplasms; of which 26769 patients were identified with either adenocarcinoma or neuroendocrine neoplasms (25847 and 922 respectively). Statistically significant associations were found for all examined variables, including age, insurance type, gender, and race/ethnicity. Patients with neuroendocrine neoplasms were more likely to be diagnosed at a younger age (z=14.7) than at age greater than 70 years (z=-6.6) compared to the adenocarcinoma group. Similarly, there was a higher incidence of male patients with neuroendocrine tumors (z=4.4, OR=1.3) than the adenocarcinoma group. Patients with neuroendocrine neoplasms were more likely to have private insurance payor sources (z=5.7) than Medicare (z=-4.7) compared to the adenocarcinoma group. Notably, Black individuals exhibited a higher prevalence of neuroendocrine cancers (z=3.7), whereas Asian/Pacific Islanders were less likely to develop this cancer (z=-2). There was a significant increase in the incidence of neuroendocrine neoplasms beginning in 2016 (z=2.4), while the incidence of adenocarcinoma remained stable.
Conclusion:
This study identified significant differences in the incidence and trends in neuroendocrine neoplasms of the gallbladder compared to adenocarcinoma. These significant differences warrant further investigation into the mechanisms of gallbladder neuroendocrine neoplasms pathogenesis.
