Gallbladder neuroendocrine carcinoma diagnosis, treatment and prognosis based on the SEER database: A literature review

BACKGROUND Gallbladder neuroendocrine carcinoma (GB-NEC) has a low incidence rate; therefore, its clinical characteristics, diagnosis, treatment and prognosis are not well explored. AIM To review recent research and analyze corresponding data in the Surveillance Epidemiology and End Results (SEER) database. METHODS Data of GB-NEC (n = 287) and gallbladder adenocarcinoma (GB-ADC) (n = 19 484) patients from 1975 to 2016 were extracted from the SEER database. Survival analysis was performed using Kaplan-Meier and Cox proportional hazards regression. P < 0.05 was considered statistically significant. We also reviewed 108 studies retrieved from PubMed and Reference Citation Analysis (https://www.referencecitationanalysis.com/). The keywords used for the search were: "(Carcinoma, Neuroendocrine) AND (Gallbladder Neoplasms) ". RESULTS The GB-NEC incidence rate was 1.6% (of all gallbladder carcinomas), male to female ratio was 1:2 and the median survival time was 7 mo. The 1-, 2-, 3- and 5-year overall survival (OS) was 36.6%, 17.8%, 13.2% and 7.3% respectively. Serum chromogranin A levels may be a specific tumor marker for the diagnosis of GB-NEC. Elevated carcinoembryonic antigen, carbohydrate antigen (CA)-19-9 and CA-125 levels were associated with poor prognosis. Age [hazard ratio (HR) = 1.027, 95% confidence interval (CI): 1.006-1.047, P = 0.01] and liver metastasis (HR = 3.055, 95% CI: 1.839-5.075, P < 0.001) are independent prognostic risk factors for OS. Patients with advanced GB-NEC treated with surgical resection combined with radiotherapy and/or chemotherapy may have a better prognosis than those treated with surgical resection alone. There was no significant difference in OS between GB-NEC and GB-ADC. CONCLUSION The clinical manifestations and prognosis of GB-NEC are similar to GB-ADC, but the treatment is completely different. Early diagnosis and treatment are the top priorities.