Incidence of additional primary cancers in patients with invasive intraductal papillary mucinous neoplasms and sporadic pancreatic adenocarcinomas.

BACKGROUND: Recent small studies have reported an incidence of 23% to 39% for additional primary cancers in patients with intraductal papillary mucinous neoplasms (IPMN) of the pancreas. There have been no population-based studies evaluating this incidence rate.
METHODS: Using the Surveillance, Epidemiology, and End Results (SEER) database (1983 to 1991), we identified all patients with primary pancreatic cancers (sporadic and adenocarcinomas arising in IPMNs). We determined the incidence of additional primary cancers that developed either before or after the diagnosis of invasive IPMN and compared it to the incidence of additional primary cancers in patients with sporadic pancreatic adenocarcinoma.
RESULTS: Nineteen thousand six hundred forty-seven patients were reported with pancreatic cancer. Ninety-five percent of cancers were sporadic and 5.0% were invasive IPMNs. Ten point three percent had one or more extra-pancreatic primary cancers in addition to their pancreatic primary (10.3% in patients with sporadic adenocarcinoma and 10.1% in patients with invasive IPMNs, p = NS). The most common sites of additional primary cancers were colorectal (20.1%), breast (19.9%), prostate (16.6%), urinary system (11.1%), and lung (9.8%). In the 2,017 patients with additional primary cancer, 86% occurred before the diagnosis of pancreatic cancer and 14% occurred after the diagnosis of pancreatic cancer.
CONCLUSIONS: Our population-based analysis shows that the incidence of additional primary malignancies in patients with invasive IPMNs is 10%. Although not as high as previously reported in smaller studies, the incidence is significant and comparable to the incidence seen in patients with adenocarcinoma. Surveillance for other common malignancies in patients with IPMNs and pancreatic adenocarcinomas should be performed.