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.