Characteristics of Small Pancreatic Carcinoma: Neural Invasion is Associated with Tumor Recurrence

Background: Pancreatic carcinoma has a poor prognosis. It is important to focus on early detection and treatment for improvement of the prognosis. Understanding the characteristics of TS1 pancreatic carcinoma (≤2 cm) could improve the treatment outcome of pancreatic carcinoma. Methods: Among 444 patients with conventional pancreatic carcinoma who underwent surgery at our facility, the study targeted 65 (14.6%) with a histopathological diagnosis of TS1 pancreatic carcinoma. We examined 65 cases of TS1 pancreatic carcinoma in reason for hospital visit, examination findings, histopathological findings, and treatment outcomes. Results: The detection rate of TS1 pancreatic carcinoma by ultrasonography was 83.1% for visualization of the tumor mass and 96.9% for main pancreatic duct dilatation. The corresponding rates for endoscopic ultrasound were 92.9% and 100%. With regard to postoperative outcome, 43.1% of patients had a recurrence; the site of recurrence was local in 24.6% and hepatic in 9.2%. On multivariate analysis, intrapancreatic neural invasion was an independent risk factor for recurrence (odds ratio, 6.333; 95% confidence interval, 1.834 - 21.872; p = 0.004). Conclusions: To screen for TS1 pancreatic carcinoma, the study first examined for main pancreatic duct dilatation by ultrasonography and then conducted a detailed examination with endoscopic ultrasound. Patients with pancreatic neural invasion require careful attention for local recurrence.