A Nomogram for Predicting the Probability of Carcinoma in Patients with Intraductal Papillary-Mucinous Neoplasm

A representation and interpretation of the area under a receiver operating characteristic (ROC) curve obtained by the "rating" method, or by mathematical predictions based on patient characteristics, is presented. It is shown that in such a setting the area represents the probability that a randomly chosen diseased subject is (correctly) rated or ranked with greater suspicion than a randomly chosen non-diseased subject. Moreover, this probability of a correct ranking is the same quantity that is estimated by the already well-studied nonparametric Wilcoxon statistic. These two relationships are exploited to (a) provide rapid closed-form expressions for the approximate magnitude of the sampling variability, i.e., standard error that one uses to accompany the area under a smoothed ROC curve, (b) guide in determining the size of the sample required to provide a sufficiently reliable estimate of this area, and (c) determine how large sample sizes should be to ensure that one can statistically detect differences in the accuracy of diagnostic techniques.

Non-inflammatory cystic lesions of the pancreas are increasingly recognized. Two distinct entities have been defined, i.e., intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN). Ovarian-type stroma has been proposed as a requisite to distinguish MCN from IPMN. Some other distinct features to characterize IPMN and MCN have been identified, but there remain ambiguities between the two diseases. In view of the increasing frequency with which these neoplasms are being diagnosed worldwide, it would be helpful for physicians managing patients with cystic neoplasms of the pancreas to have guidelines for the diagnosis and treatment of IPMN and MCN. The proposed guidelines represent a consensus of the working group of the International Association of Pancreatology.

The aim of this study was to determine recurrence and long-term survival after resection of pancreatic intraductal papillary mucinous neoplasm and to correlate recurrence and survival with histology, extent of resection, and duration of follow-up. A single pathologist, without knowledge of previous interpretations of histology or clinical data, retrospectively reviewed and classified 113 resected intraductal papillary mucinous neoplasms as invasive carcinoma (n = 40) or as noninvasive neoplasms (adenoma, borderline, or carcinoma in situ; n = 73). Data on recurrence (locoregional or metastatic), follow-up, and cause of death were obtained from patient records and/or by contacting patients and their physicians. In invasive intraductal papillary mucinous neoplasm, recurrence was similar after partial pancreatectomy (18/27; 67%) and total pancreatectomy (8/13; 62%) and occurred within 3 years of resection in 91%. Among noninvasive neoplasms, 5 of 60 (8%) recurred after partial pancreatectomy (median follow-up, 37 months); none recurred after total pancreatectomy (n = 13; median follow-up, 32 months). Recurrence after resection in noninvasive neoplasms was diagnosed after a median of 40 months (range, 23-75 months); recurrence was noninvasive in 3 and invasive cancer in 2. Five-year survival was better for noninvasive compared with invasive intraductal papillary mucinous neoplasm (84.5% vs. 36%; P < 0.001). Invasive intraductal papillary mucinous neoplasm recurs frequently even after a complete "curative" resection and portends poor survival. In contrast, noninvasive intraductal papillary mucinous neoplasm recurs infrequently after resection, and survival is excellent regardless of the degree of epithelial dysplasia in the tumor.