Pancreatic cancer in patients with pancreatic cystic lesions: a prospective study in 197 patients.
OBJECTIVE
K-ras mutation is frequently detected in pancreatic juice of patients with pancreatic small cystic lesions, as well as those with pancreatic cancer. Those cystic lesions are often found by chance with modern radiologic imaging modalities. In this study, we prospectively examined the prognosis of patients with pancreatic cystic lesions, focusing on pancreatic cancer development.


METHODS
A total of 197 patients with pancreatic cystic lesions, 80 with intraductal papillary mucinous neoplasm (IPMN) and 117 with non-IPMN cysts, were followed up for 3.8 years on average. Blood tests and imaging diagnosis were performed twice a year. The observed incidence of pancreatic cancer was compared with the expected incidence calculated on the basis of age- and gender-matched mortality of pancreatic cancer in the general Japanese population.


RESULTS
Pancreatic cancer developed in 7 patients during the observation period (0.95% per year), infiltrating ductal carcinoma in 5 and intraductal papillary mucinous carcinoma in 2. Three of the ductal cancer cases had pancreatic non-IPMN cyst as preexisting lesion. At least 2 of the carcinomas arose in regions remote from preexisting lesions. The observed incidence of pancreatic cancer was 22.5 times higher (95% confidence interval, 11.0-45.3) than expected mortality from this cancer among general population.


CONCLUSIONS
Patients with pancreatic cystic lesions are at a considerably high risk for pancreatic cancer, with a standardized incidence rate of 22.5. Cancer might develop in regions remote from the preexisting cystic lesion, suggesting diffuse pathologic changes predisposing to malignant transformation in the entire pancreas harboring cystic lesions.
Tada
Minoru
M
Department of Gastroenterology, University of Tokyo, Tokyo, Japan. mtada-tky@umin.ac.jp
Kawabe
Takao
T
Arizumi
Masatoshi
M
Togawa
Osamu
O
Matsubara
Saburo
S
Yamamoto
Natsuyo
N
Nakai
Yosuke
Y
Sasahira
Naoki
N
Hirano
Kenji
K
Tsujino
Takeshi
T
Tateishi
Keisuke
K
Isayama
Hiroyuki
H
Toda
Nobuo
N
Yoshida
Haruhiko
H
Omata
Masao
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D002291:Carcinoma, Papillary / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D049448:Cholangiopancreatography, Magnetic Resonance; D018450:Disease Progression; D019160:Endosonography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010181:Pancreatic Cyst / Q000150:complications* / Q000175:diagnosis; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed