Comparative effectiveness of chemotherapy in different histological types of pancreatic cancer: a PSM-based study using the SEER database

This study aimed to compare the effectiveness of chemotherapy in different histological types of pancreatic cancer using data collected from the Surveillance, Epidemiology, and End Results (SEER) database. Patients who were diagnosed with pancreatic cancer between 2004 and 2015 were selected from the SEER database. Propensity score matching (PSM) was employed to minimize the selection bias. The Kaplan-Meier survival curves and the log-rank test were utilized to compare the overall survival (OS) and cancer-specific survival (CSS) among different groups. Of the 7,653 pancreatic cancer patients, both OS and CSS were higher in the chemotherapy group than those in the non-chemotherapy group (p < 0.001). After PSM, 2381 pairs were generated. The Kaplan-Meier survival curved indicated that both OS and CSS for pancreatic ductal adenocarcinoma (PDAC), pancreatic adenosquamous carcinoma (PASC), and pancreatic mucin-producing adenocarcinoma (PMPAC) (p < 0.001) in the chemotherapy group were superior to those in the non-chemotherapy group, while there was no significant difference in pancreatic mucinous adenocarcinoma (PMAC) (p = 0.2586). Compared with PASC and PMPAC, PDAC exhibited longer OS and CSS. The results of statistical analysis showed that PASC tumors were mainly poorly differentiated, and the majority of patients with PMPAC had distant metastasis. Chemotherapy could prolong pancreatic cancer patients' survival, especially for patients with advanced disease. PMPAC patients had a higher rate of metastasis, accompanying with the worse survival.