Impact of radiologic splenic vessel invasion in resectable left-sided pancreatic ductal adenocarcinoma: predictor of early systemic recurrence following upfront surgery

BACKGROUND: The aim of this study is to identify prognostic factors and the best candidates for neoadjuvant therapy among patients with resectable left-sided pancreatic ductal adenocarcinoma (PDAC) by analyzing the timing and pattern of recurrence following upfront surgery. METHODS: This single-center retrospective study included patients with resectable left-sided PDAC who underwent upfront distal pancreatectomy from 2005 to 2015. A minimum P value approach was used to evaluate the optimal cutoff of early recurrence. The predictors of recurrence were assessed with Cox regression analysis. RESULTS: Among 311 included patients, 241 (77.5%) had a recurrence at a median follow-up of 29.3 months. Systemic recurrence occurred in 194 patients (80.5%) and isolated local recurrence in 47 patients (19.5%). A recurrence-free survival cutoff of 12 months was selected to distinguish between early and late recurrence. The patients with early recurrence had a shorter median overall survival (16.1 vs. 39.9 months, P<0.001) and post-recurrence survival (9.6 vs. 17.2 months, P<0.001) than those with late recurrence. The patients with systemic recurrence had a shorter median overall survival (19.6 vs. 29.1 months, P=0.007) and post-recurrence survival (11.0 vs. 15.3 months, P=0.024) than those with an isolated local recurrence. In multivariable analysis, preoperative CA 19-9 ≥500 U/mL [odd ratio (OR) 2.037, P=0.035], radiologic splenic vessels invasion (OR 5.014, P<0.001), positive radial resection margin (OR 2.638, P<0.001), and no adjuvant chemotherapy (OR 2.084, P=0.001) were predictors of an early systemic recurrence. CONCLUSIONS: Radiologic splenic vessels invasion may be considered to indicate a biologically borderline status in patients with anatomically resectable left-sided PDAC. Future clinical trials of neoadjuvant therapy targeting these patients should be conducted.