Addition of radiotherapy to adjuvant chemotherapy is associated with improved overall survival in resected pancreatic adenocarcinoma: An analysis of the National Cancer Data Base

Abstract

BACKGROUND:The optimal treatment for resected pancreatic cancer is controversial because direct comparisons of adjuvant chemotherapy (CT) alone and chemotherapy and radiotherapy (CRT) are limited. This study assessed outcomes of CT versus CRT in a national cohort to provide a modern estimate of comparative effectiveness. METHODS: Patients with pT1-3N0-1M0 pancreatic adenocarcinoma after pancreatectomy were identified in the National Cancer Data Base. Overall survival (OS) was compared for CT and CRT groups with Cox regression and propensity score matching. Subset analyses by clinicopathologic characteristics were performed. RESULTS: This study identified 6165 patients treated with CT (n 5 2334 or 38%) or CRT (n 5 3831 or 62%). Most were classified as pT3 (72%), pN1 (67%), and status-post R0 resection (84%). For CRT patients, the median radiotherapy dose was 50.4 Gy. Compared with CT, CRT was associated with improved OS in a univariate analysis (median, 20.0 vs 22.3 months; at 5 years, 16.5% vs 19.6%; P <.001) and a multivariate analysis (hazard ratio [HR], 0.893; 95% confidence interval [CI], 0.837-0.953; P 5.001). CRT remained associated with improved OS after propensity score matching (HR, 0.851; 95% CI, 0.793-0.913; P <.001). Subset analyses showed that CRT was associated with improved OS among patients with pT3 (HR, 0.892; 95% CI, 0.828-0.962; P 5.003) or pN1 disease (HR, 0.856; 95% CI, 0.793-0.924; P <.001) and both R0 resection (HR, 0.901; 95% CI, 0.839-0.969; P 5.005) and R1 resection (HR, 0.842; 95% CI, 0.722-0.983; P 5.030). CONCLUSIONS: CRT was independently associated with improved OS after the resection of pancreatic adenocarcinoma in a large national cohort and particularly among patients with R1 resection and pN1 disease. Well-designed randomized comparisons of CRT and CT are urgently needed. Cancer 2015;121:4141-9.

Risk Factors Associated With Locoregional Failure After Surgical Resection in Patients With Resectable Pancreatic Cancer

“…[19][20][21][22][23] A retrospective study from the Mayo Clinic that included 472 patients investigated outcomes after surgery alone versus surgery plus adjuvant CRT. OS was better in patients who received adjuvant CRT (median OS, 25.2 vs. 19.2 months, P = 0.001).…”

“…Adjuvant CRT was independently associated with improved OS compared with adjuvant chemotherapy (median 22.3 vs. 20.0 months, P = 0.001). [23] The benefit of adjuvant RT with modern techniques is still controversial and the subgroup that can benefit most from this approach is not well defined. A well-designed randomized controlled study with modern techniques will be necessary to confirm the efficacy of adjuvant CRT in this population.…”

Evolving treatment landscape for early and advanced pancreatic cancer

“…Several contemporary retrospective studies suggest that there is a survival benefit[36-39]. Rutter et al[36] reviewed the national cancer database in the United States and identified 6165 patients from 1998 to 2009 who were treated with adjuvant chemotherapy or chemoradiotherapy. The mean radiotherapy dose received was 50.4 Gy, which was higher than the doses used in older prospective studies.…”

Dose-escalated radiotherapy for unresectable or locally recurrent pancreatic cancer: Dose volume analysis, toxicity and outcome of 28 consecutive patients

“…Current data suggests that a consolidative approach after completing systemic treatment options and careful restaging might be reasonable. A positive role of post-operative radiotherapy was confirmed by a large retrospective analysis [13] which identified radiotherapy in addition to adjuvant chemotherapy as a favorable prognostic indicator for survival.…”