Does adjuvant chemoradiotherapy improve the prognosis of gastric cancer after an r1 resection? Results from a dutch cohort study.

OBJECTIVE: The aim of this study was to investigate the impact of adjuvant chemoradiotherapy (CRT) on survival of non-metastatic gastric cancer patients who had undergone an R1 resection.

METHODS: We compared the survival of patients after an R1 gastric cancer resection from the population-based Netherlands Cancer Registry who did not receive adjuvant CRT (no-CRT group) with the survival of resected patients who had been treated with adjuvant CRT (CRT group) at our institute. Patients who had a resection between 2002 and 2011 were included. CRT consisted of radiotherapy (45 Gy) combined with concurrent cisplatin- or 5-fluorouracil-based chemotherapy. The impact of CRT treatment on overall survival was assessed using multivariable Cox regression and stratified propensity score analysis.

RESULTS: A series of 409 gastric cancer patients who had undergone an R1 resection were studied (no-CRT, N = 369; CRT, N = 40). In the no-CRT group, median age was higher (70 vs. 57 years; p < 0.001) and the percentage of patients with diffuse-type tumors was lower (43 vs. 80 %; p < 0.001). There were no significant differences in pathological T- and N-classification. There was a significant difference in median overall survival between the no-CRT and CRT group (13 vs. 24 months; p = 0.003). In a multivariable analysis, adjuvant CRT was an independent prognostic factor for improved overall survival (hazard ratio 0.54; 95 % confidence interval 0.35-0.84). This effect of CRT was further supported by propensity score analysis.

CONCLUSIONS: Adjuvant CRT was associated with an improved survival in patients who had undergone an R1 resection for gastric cancer.