title: Does adjuvant chemoradiotherapy improve the prognosis of gastric cancer after an r1 resection? Results from a dutch cohort study.
abstract: 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.
authors.affiliation: Department of Surgery, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Jurriën
authors.initials: J
authors.lastname: Stiekema
authors.forename: Anouk K
authors.initials: AK
authors.lastname: Trip
authors.forename: Edwin P M
authors.initials: EP
authors.lastname: Jansen
authors.forename: Mieke J
authors.initials: MJ
authors.lastname: Aarts
authors.forename: Henk
authors.initials: H
authors.lastname: Boot
authors.forename: Annemieke
authors.initials: A
authors.lastname: Cats
authors.forename: Olga Balague
authors.initials: OB
authors.lastname: Ponz
authors.forename: Patrycja L
authors.initials: PL
authors.lastname: Gradowska
authors.forename: Marcel
authors.initials: M
authors.lastname: Verheij
authors.forename: Johanna W
authors.initials: JW
authors.lastname: van Sandick
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D000368:Aged; D059186:Chemoradiotherapy, Adjuvant; D015331:Cohort Studies; D005260:Female; D005743:Gastrectomy / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012042:Registries; D013274:Stomach Neoplasms / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D016019:Survival Analysis