Study data published in Cancer Epidemiology characterize neuroendocrine tumors and neuroendocrine carcinomas as prognostically distinct subgroups of pancreatic neuroendocrine neoplasms. Currently, cancer registry reporting of pancreatic cancers does not stratify by these subgroups. However, in an analysis of 2 population-based cancer registries, survival rates were significantly higher in neuroendocrine tumors compared with neuroendocrine carcinomas. The study findings support the separation of these tumors into distinct reporting categories, such that trends in pancreatic cancers can be more precisely elucidated.
Researchers extracted data from 2 cancer registries in Germany: North Rhine-Westphalia (NRW) and Saarland (SL). Patients aged 0 to 79 years with malignant pancreatic cancers diagnosed between 2009 and 2018 were included in the study. International Classification of Diseases for Oncology (ICD-O) morphology codes were used to categorize cancers as adenocarcinoma or as 1 of the subgroups of neuroendocrine neoplasms: neuroendocrine carcinomas or neuroendocrine tumors. Using annual population data from Germany, researchers calculated age-specific and age-standardized incidence rates of each cancer subtype by sex. Age-standardized relative survival was computed as the ratio of observed survival compared to expected survival in a comparative cohort of patients without cancer.
The cancer registries recorded a total of 23,037 malignant pancreatic cancer cases from 2009 to 2018. The majority of cases were men in both the NRW (54.5%) and SL (54.3%) cohorts. Most patients were diagnosed between ages 60 and 79 years (>76% in both cohorts). Among morphologically specified tumors, the most common subtypes were adenocarcinoma (92%) and neuroendocrine neoplasms (7%). The age-standardized incidence rates of adenocarcinoma were 4.0 per 100,000 person-years in NRW and 5.5 per 100,000 person-years in SL. The rates of neuroendocrine tumors and neuroendocrine carcinomas were 0.1 to 0.3 (NRW-SL), and 0.1 to 0.3 (NRW-SL) per 100,000 person-years, respectively. Neuroendocrine tumors had an age-standardized 5-year relative survival of 75.5% (standard error [SE], 2.3) in NRW and 90.6% (SE, 10.2) in SL. Neuroendocrine carcinomas had lower relative survival rates, at 30.0% (SE, 1.3) in NRW and 32.3% (SE, 8.7%) in SL. Finally, adenocarcinomas had the lowest survival rate for both NRW (11.3%; SE, 0.4) and SL (10.2%; SE, 1.5).
Five-year relative survival was significantly higher in patients younger than 50 years of age compared with older patients. This association persisted across morphological subtypes, with the lowest survival observed in patients aged 70 to 79 years. Comparing cancer sites, cancer of the pancreatic tail had the greatest 5-year relative survival. Stages T1 to T2 also had greater survival compared with stages T3 to T4.
In this analysis of population-based German pancreatic cancer registries, neuroendocrine tumors had the best prognosis, followed by neuroendocrine carcinomas and adenocarcinomas.
Study limitations include a potential overestimation of patients with malignant pancreatic tumors due to death certificate only cases, which were excluded from the analysis. Data were also missing for T-stage and anatomical subsites.
“In conclusion, the distinction of neuroendocrine neoplasms in neuroendocrine tumors and neuroendocrine carcinomas by the WHO results in two prognostically clearly distinct subgroups that should always be analyzed separately in terms of survival,” the study authors wrote. “The first year after diagnosis of pancreatic cancer is the most critical year in terms of survival.”
Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of the author’s disclosures.
Stang A, Wellmann I, Holleczek B, et al. Incidence and relative survival of pancreatic adenocarcinoma and pancreatic neuroendocrine neoplasms in Germany, 2009-2018. An in-depth analysis of two population-based cancer registries. Cancer Epidemiol. 2022;79:102204. doi:10.1016/j.canep.2022.102204