Are Patients with Intraductal Papillary Mucinous Neoplasm (IPMN) of Pancreas Likely to Carry Colorectal Neoplasia?

Background and Aims: Although there have been several reports showing the high prevalence of extrapancreatic malignant neoplasms in patients with intraductal papillary mucinous neoplasm (IPMN) of pancreas, few reports have indicated the prevalence of colorectal neoplasia in patients with IPMN on follow-up. In this study, we performed a case-control study to investigate whether the prevalence of colorectal neoplasia in patients with IPMN is higher compared to that in the control subjects. Patients and Methods: We performed a retrospective chart review analysis on 58 patients with IPMN (mean age 67.5 ± 9.1 years; 64% male; 4 (7%) main duct type, 49 (84%) branch duct type, 4 (7%) mixed type, and 1 (2%) unknown) who underwent colonoscopy at our hospital and its 4 affiliated hospitals between June 1998 and June 2008. Among 58 patients, 11 cases had undergone surgical resection of IPMN, while 47 cases were being followed-up without operation. The control group was comprised of age- and gender-matched 174 asymptomatic subjects who underwent colonoscopy for the first time during the study period. Findings of colonoscopy for these subjects were investigated. Results: Among 58 patients with IPMN, neoplasia was found in 24 (41%), and invasive cancer was found in 2 (3%). In the control group, neoplasia was found in 74 (43%), and invasive cancer was found in 1 (1%). There were no statistically significant differences in the prevalence of neoplasia (p>0.99), and invasive cancer (p=0.16) between patients with IPMN and the control group. In the patients with IPMN, the prevalence of colorectal neoplasia was relatively higher in men than in women (75% vs. 56%, p=0.17), and the patients with neoplasia were relatively older than those without neoplasia (mean age; 69.3 ± 7.86 vs. 66.3 ± 9.84 years, p=0.23). Among 8 patients with main duct IPMN or mixed type IPMN, which frequently contains pancreatic cancer component, advanced neoplasia (adenoma ≥ 10 mm, adenoma with high-grade dysplasia, or invasive cancer) was found in 2 (25%; one case had invasive cancer), while among 49 patients with branch duct IPMN, advanced neoplasia was found in 5 (10%) (p=0.25). This suggests that patients with IPMN with high malignant potential may be likely to carry advanced neoplasia in the colon. Conclusions: There were no statistically significant differences in the prevalence of neoplasia between patients with IPMN and the control group. However, patients with main duct IPMN or mixed type IPMN may be likely to carry advanced neoplasia in the colon. For these patients, colonoscopy should be recommended.