Clinicopathological aspects of small pancreatic cancer.

Small pancreatic cancers, intractable diseases, offer the possibility of cure. Can this be true? Through the National Pancreatic Cancer Registry, the Japan Pancreas Society (JPS) has collected 822 cases of invasive cancer with tumors <2 cm in diameter (TS1 pancreatic cancer). Papillary adenocarcinoma and the well-differentiated type of tubular adenocarcinoma are more frequent in TS1 pancreatic cancer than the larger tumors, suggesting that further genetic and phenotypic changes occur during their progression. Patients with TS1 pancreatic cancer presented with abdominal pain, jaundice, and exacerbation of diabetes, while 17.3% of them had no symptoms. Further imaging diagnosis should be employed to detect TS1 pancreatic cancer, but conventional US and ERCP play an important role in the diagnostic process. In this study, of 822 patients with TS1 pancreatic cancer, only 216 patients (26.3%) had T1 tumors because of invasion to adjacent tissue. There were 306 patients (37.2%) with lymph node metastasis, of whom 63 (7.7%) had N3 metastasis that is counted as a distant metastasis. As a result, only 136 patients (16.5%) had stage I disease with a median survival time of 78.2 months and a 5-year survival rate of 58.1%. Small pancreatic cancer does not necessarily mean early pancreatic cancer, and surgery alone is not sufficient to cure this disease.