A population-based, descriptive analysis of malignant intraductal papillary mucinous neoplasms of the pancreas

Background: Intraductal papillary mucinous neoplasms (IPMN) are distinct precursor lesions that can progress to pancreatic adenocarcinoma; thus, it has been of particular interest to cancer prevention researchers. We set out to do a population-based analysis of malignant IPMNs compared with other pancreatic subtypes to better delineate its characteristics and explore implications for prevention and management. Methods: We conducted a case-only analysis of California Cancer Registry data (2000-2007), including descriptive analysis of relevant clinical variables. Overall survival univariate analyses were conducted using the Kaplan-Meier method. Multivariate survival analyses were done using Cox proportional hazards ratios. Results: Overall, 15,296 pancreatic cancer cases were identified, including incident cases of 10,186 adenocarcinomas, 880 mucinous tumors, 568 endocrine tumors, 3,619 carcinoma not otherwise specified tumors, and 43 malignant IPMNs. Thirty-three (80.5%) IPMN cases had localized disease at presentation, eight had regional disease (19.5%), and no IPMNs were identified with distant disease (two were unstaged). Five-year overall survival was better for malignant IPMN cases (65%) compared with pancreatic endocrine tumors (30%), mucinous tumors (5%), carcinoma not otherwise specified (2%), and adenocarcinoma cases (2%). Compared with adenocarcinoma cases, malignant IPMN cases (hazard ratio = 0.19; 95% CI, 0.10-0.35), endocrine tumors (hazard ratio = 0.28; 95% CI, 0.25-0.32), and mucinous tumors (hazard ratio = 0.84; 95% CI, 0.77-0.90) had higher overall survival in a multivariate survival analysis after adjustment for age, gender, stage, race, socioeconomic status, surgery, chemotherapy, and radiation therapy. Conclusions: Pancreatic malignant IPMNs represent an uncommon pancreatic tumor subtype, uniquely characterized by early stage at presentation and better survival.