Su1227 Clinicoradiologic Characteristics Between Metastatic Pancreatic Cancer and Double Primary Pancreatic Cancer

Abstract

Background: Pancreatic mass in a patient with a history of another malignancy is confusing. As metastatic pancreatic cancer is relatively rare disease, there are no clinical or radiologic data comparing metastatic pancreatic cancer and double primary pancreatic cancer. The goal of this study is to suggest clinicoradiologic characteristics that could help distinguishing metastatic pancreatic cancer from double primary pancreatic cancer. Methods: From 2000 to 2011, we retrospectively identified metastatic or double primary pancreatic cancer patients among those who had a history of another primary malignancy. Results: A total of 94 patients with a history of another malignancy were histologically confirmed to have pancreatic cancers. Among them 34 patients had metastatic tumors to pancreas (MTPs) and 60 patients had double primary pancreatic adenocarcinoma (DPPAC). RCC was the most common primary cancers that metastasized to pancreas (12, 35.3%). In DPPAC group, gastric cancer and colorectal cancer were the most common primary cancer sites before the patients had pancreatic cancer (11, 18.3%; 10, 16.7%). The number of the patients who had a metachronous pancreatic cancer was 21 (61.8%) in MTP group and 29 (48.3%) in DPACC group (p= 0.210). Among the metachronous pancreatic cancer patients the disease free interval was 88.3 months in MTP group, which was 49.6 months in DPACC group (p=0.062). In the laboratory finding, the number of the patients who showed elevated CA 19-9 was higher in MTP group than DPPAC group (39 (65%) vs. 9 (26.5%), p=0.001). Also total bilirubin (p=0.006) and fasting glucose (0.050) were higher in DPPAC group. In the radiologic finding, the patients who showed pancreatic duct dilatation (p=0.002) and pancreatic atrophy (p= 0.008) were meaningfully higher in DPPAC group. On the other hand, the number of patients who showed well demarcated tumor margin (p<0.000), tumor necrosis (p=0.002), enhancement (p=0.005) and distant metastasis (p=0.028) were significantly higher in MTP group. We also evaluate the survival between two groups. The median survival times were 20 months in DPPAC group and 55 months in MTP group, which was a lot better in metastasis group. Conclusion: Other than CA 19-9 elevation, total bilirubin and fasting glucose, radiologic findings are the most reliable factors that could help diagnosing metastatic pancreatic cancer from double primary pancreatic cancer. Difference of radiologic findings between MTP and DPPAC