Incidence, Treatment, and Survival of Synchronous Peritoneal Metastases in Pancreatic Cancer: Update of a Nationwide Cohort

OBJECTIVE The aim of the study was to gain insight in the incidence, treatment, and survival of patients with synchronous pancreatic peritoneal metastases. METHODS All patients diagnosed with pancreatic cancer between 2008 and 2018 in the Netherlands Cancer Registry were evaluated. The patients were subcategorized as (1) synchronous peritoneal metastases, (2) synchronous systemic metastases, and (3) no metastases. RESULTS In total, 25,334 patients with pancreatic cancer were included. Among them, 3524 (14%) presented with synchronous peritoneal metastases, 10,659 (42%) with systemic metastases, and 11,151 (44%) without metastases at the time of diagnosis. The proportion of the patients diagnosed with peritoneal metastases increased over time (11%, 2008; 16%, 2018; P < 0.001). Of these patients, 964 (27%) received cancer treatment and 2560 (73%) received best supportive care. The median overall survival in patients with peritoneal metastases, systemic metastases, and without metastases was 1.9, 2.4, and 8.0 months, respectively (P < 0.001). In the patients with peritoneal metastases, the median overall survival was 5.0 months when undergoing cancer treatment and 1.3 months with best supportive care (P < 0.001). CONCLUSIONS Patients with pancreatic cancer are increasingly diagnosed with synchronous peritoneal metastases. Given the current dismal prognosis, research to improve treatment is designated for this patient category.