Prognostic Value of Splenic Artery Invasion in Patients Undergoing Adjuvant Chemoradiotherapy after Distal Pancreatectomy for Pancreatic Adenocarcinoma

PURPOSE: The purpose of this study was to evaluate the outcome of adjuvant chemoradiotherapy (CRT) after distal pancreatectomy (DP) in patients with pancreatic adenocarcinoma, and to identify the prognostic factors for these patients. MATERIALS AND METHODS: We performed a retrospective review of 62 consecutive patients who underwent curative DP followed by adjuvant CRT between 2000 and 2011. There were 31 men and 31 women, and the median age was 64 years (range, 38 to 80 years). Adjuvant radiotherapy was delivered to the tumor bed and regional lymph nodes with a median dose of 50.4 Gy (range, 40 to 55.8 Gy). All patients received concomitant chemotherapy, and 53 patients (85.5%) also received maintenance chemotherapy. The median follow-up period was 24 months. RESULTS: Forty patients (64.5%) experienced relapse. Isolated locoregional recurrence developed in 5 patients (8.1%) and distant metastasis in 35 patients (56.5%), of whom 13 had both locoregional recurrence and distant metastasis. The median overall survival (OS) and disease-free survival (DFS) were 37.5 months and 15.4 months, respectively. On multivariate analysis, splenic artery (SA) invasion (p=0.0186) and resection margin (RM) involvement (p=0.0004) were identified as significant adverse prognosticators for DFS. Also, male gender (p=0.0325) and RM involvement (p=0.0007) were associated with a significantly poor OS. Grade 3 or higher hematologic and gastrointestinal toxicities occurred in 22.6% and 4.8% of patients, respectively. CONCLUSION: Adjuvant CRT may improve survival after DP for pancreatic body or tail adenocarcinoma. Our results indicated that SA invasion was a significant factor predicting inferior DFS, as was RM involvement. When SA invasion is identified preoperatively, neoadjuvant treatment may be considered.