Imaging diagnostic abilities for small pancreatic cancer

Background and Aim: Pancreatic cancer is a disease of poor prognosis, compared with other cancers of the digestive system, and it is often too difficult to resect when advanced tumor is detected. Even though imaging diagnostic modalities are advanced today. However it is still hard to get a pancreatic cancer image of small tumor diameter, and how to detect small resectable pancreatic cancer is an important point. In this study, we examined imaging diagnostic abilities of US, CT and EUS for small pancreatic cancer.

Subjects and Methods: Of the 375 cases of pancreatic cancer we experienced in our Center between April 1997 and December 2005, we subjected to this study 14 cases in which the tumors were smaller than 2cm in diameter. All were resected, and the pathological diagnosis was made (M:F=11:3, mean age 65.6y). Tumor sites were on pancreatic head in 9 cases and pancreatic tail in 5; pathological stages were Stage IA in 8cases, Stage IIB in 6 following the UICC Staging System. We examined 1) the tumor detection rates of US, CT and EUS. 2) the first imaging diagnostic modality which led to the tumor detection.

Results: 1) Tumor detection rates of US, CT and EUS were 6/14(42.9%), 5/14(35.7%) and 14/14(100%), respectively. 2) US and CT revealed direct tumor imaged in 3 cases; US or CT revealed dilatation of the pancreatic duct, and in which the EUS revealed tumor in 10 cases; Neither US nor CT revealed abnormality, but EUS revealed the tumor in 1 case.

Conclusion: EUS was superior in tumor detection than other modalities. US or CT could not reveal the small pancreatic tumors directly in 8/14cases (57%) and 9/14(64%); in such a case, it was thought important to assemble indirect findings by US or CT, such as dilatation of the pancreatic duct, as well as to perform close examination by EUS.