Addition of radiotherapy to adjuvant chemotherapy is associated with improved overall survival in resected pancreatic adenocarcinoma: An analysis of the National Cancer Data Base.
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 = 2334 or 38%) or CRT (n = 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 = .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 = .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 = .005) and R1 resection (HR, 0.842; 95% CI, 0.722-0.983; P = .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.
Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut.
Charles E
CE
Rutter
Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut.
Henry S
HS
Park
Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut.
Christopher D
CD
Corso
Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut.
Nataniel H
NH
Lester-Coll
Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut.
Brandon R
BR
Mancini
Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut.
Debra N
DN
Yeboa
Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut.
Kimberly L
KL
Johung
D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059186:Chemoradiotherapy, Adjuvant / Q000401:mortality*; D017024:Chemotherapy, Adjuvant / Q000401:mortality*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D057216:Propensity Score; D016016:Proportional Hazards Models; D011879:Radiotherapy Dosage; D016019:Survival Analysis; D016896:Treatment Outcome
chemoradiation; chemotherapy; pancreatic; radiation