Introduction The aim of this study was to establish if R1 resection margin after oesophagectomy was (i) a poor prognostic factor independent of patient and tumour characteristics, (ii) a marker of tumour aggressiveness and (iii) to look at the impact of adjuvant treatment in this subpopulation.

Method Data was collected from 30 European centres from 2000–2010. Patients with an R1 resection margin (n = 242) were compared to those with an R0 margin (n = 2573) in terms of short- and long-term outcomes. Propensity score matching and multivariable analyses were used to compensate for differences in baseline characteristics.

Results Important factors significantly associated with an R1 resection margin included an upper third oesophageal tumour location, preoperative malnutrition and pathological stage III. There were significant differences between the groups in postoperative histology, with an increase in pathological stage III and TRG 4/5 in the R1 group. Total average lymph node harvests were similar between the groups, however there was an increase in the number of positive lymph nodes seen in the R1 group. Propensity matched analysis confirmed R1 resection margin was significantly associated with reduced overall survival and increased overall, loco-regional, and mixed tumour recurrence. Similar findings were seen in the subgroup that received neoadjuvant chemoradiation. In R1 patients adjuvant therapy improved survival and reduced distant recurrence however failed to affect locoregional recurrence.

Conclusion This large multi-centre European study provides evidence to support the notion that R1 resection margin is a prognostic indication of aggressive tumour biology with a poor long-term prognosis.

Disclosure of interest None Declared.