RECQ1 A159C Polymorphism Is Associated With Overall Survival of Patients With Resected Pancreatic Cancer: A Replication Study in NRG Oncology Radiation Therapy Oncology Group 9704.

Abstract

To confirm whether a previously observed association between RECQ1 A159C variant and clinical outcome of resectable pancreatic cancer patients treated with preoperative chemoradiation is reproducible in another patient population prospectively treated with postoperative chemoradiation. Patients were selected, according to tissue availability, from eligible patients with resected pancreatic cancer who were enrolled on the NRG Oncology Radiation Therapy Oncology Group 9704 trial of 5-fluorouacil (5-FU)-based chemoradiation preceded and followed by 5-FU or gemcitabine. Deoxyribonucleic acid was extracted from paraffin-embedded tissue sections, and genotype was determined using the Taqman method. The correlation between genotype and overall survival was analyzed using a Kaplan-Meier plot, log-rank test, and multivariate Cox proportional hazards models. In the 154 of the study's 451 eligible patients with evaluable tissue, genotype distribution followed Hardy-Weinberg equilibrium (ie, 37% had genotype AA, 43% AC, and 20% CC). The RECQ1 variant AC/CC genotype carriers were associated with being node positive compared with the AA carrier (P=.03). The median survival times (95% confidence interval [CI]) for AA, AC, and CC carriers were 20.6 (16.3-26.1), 18.8 (14.2-21.6), and 14.2 (10.3-21.0) months, respectively. On multivariate analysis, patients with the AC/CC genotypes were associated with worse survival than patients with the AA genotype (hazard ratio [HR] 1.54, 95% CI 1.07-2.23, P=.022). This result seemed slightly stronger for patients on the 5-FU arm (n=82) (HR 1.64, 95% CI 0.99-2.70, P=.055) than for patients on the gemcitabine arm (n=72, HR 1.46, 95% CI 0.81-2.63, P=.21). Results of this study suggest that the RECQ1 A159C genotype may be a prognostic or predictive factor for resectable pancreatic cancer patients who are treated with adjuvant 5-FU before and after 5-FU-based chemoradiation. Further study is needed in patients treated with gemcitabine to determine whether an association exists.