Adjuvant chemoradiation may improve survival over adjuvant chemotherapy in resected pancreatic cancer patients who are high risk for locoregional recurrence

Abstract

The objective of the study was to evaluate the benefit of adjuvant chemoradiation compared to adjuvant chemotherapy for resected pancreatic head cancer. Three hundred thirty-nine patients (2000–2012) had pancreatoduodenectomy for pancreatic cancer. Chemotherapy was gemcitabine or 5-fluorouracil (5-FU) and radiotherapy was 45–54 Gy. Locoregional recurrences (LRR) were operative bed or regional nodal failures. Logistical regression, Kaplan-Meier estimates, and log-rank tests were used for statistics. One hundred thirty patients had resection alone (A), 84 had adjuvant chemotherapy (B), and 129 had adjuvant chemoradiation (C). Median follow-up and median survival (MS) for all patients was 17.5 and 19.5 months, respectively. MS for groups A, B, and C were 13, 23, and 26 months, respectively. Groups B and C had R1 resection rates of 37 and 39 % (p = ns). LRR was 60, 63, and 38 % and distant failure was 64, 65, and 66 % for groups A, B, and C, respectively. Group C had significantly lower LRR compared to group B (p = 0.01); however, survival between groups B and C was not statistically different (p = 0.23). On univariate analysis, LRR (p = 0.0038), N-category (p < 0.0001), perineural invasion (PNI; p = 0.007), and R1 resection (p = 0.018) were significant predictors of survival. Multivariable analysis (MVA) showed that LRR (p = 0.004) and N-category (p = 0.01) were predictors of survival. On subgroup analysis, there was improved survival in group C vs B in patients with R1 resection, MS of 27 vs 16 months, respectively (p = 0.01), and in patients with lymph node ratio (LNR) ≤0.2 who had ≥8 LN dissected, MS of 32 vs 24 months (p = 0.04). Adjuvant chemoradiation significantly decreases LRR in resected pancreatic cancer patients compared to adjuvant chemotherapy. Significant predictors of survival on MVA were LRR and N-category. Additionally on subgroup analysis, chemoradiation improved survival over chemotherapy with a (1) positive surgical margin and/or (2) LNR ≤0.2 with ≥8 LNs dissected.