681 PATTERN OF RECURRENCE IN PATIENTS WITH A PATHOLOGICALLY COMPLETE RESPONSE AFTER NEOADJUVANT CHEMORADIOTHERAPY AND SURGERY FOR OESOPHAGEAL CANCER

Neoadjuvant chemoradiotherapy (nCRT) and surgery is a widely used treatment for locally advanced resectable oesophageal cancer, with 20 and 50% of patients having a pathological complete response (pCR). Disease, however, still recurs in 20–30% of these patients. The aim of this study was to assess the pattern of recurrence in patients with pCR after nCRT and surgery. Methods All patients with pCR after neoadjuvant chemoradiotherapy and surgery included in the phase II and III ChemoRadiotherapy for Oesophageal followed by Surgery Study (CROSS) trials (April 2001—March 2009) and after the CROSS trials (September 2009—October 2017) were identified. The site of recurrence was compared to the applied radiation and surgical fields. Outcomes were median time to recurrence, overall and progression-free survivals. Results A total of 141 patients with a median follow-up of 100 (interquartile range [IQR] 64–134) months were included. Some 29 of 141 patients (21%) developed recurrence. Of these, four (14%) had isolated locoregional recurrence, 15 (52%) distant recurrence only and ten (34%) had both locoregional and distant recurrence. Among the 14 patients with locoregional recurrences, five were within the radiation field, seven outside the radiation field and two at the border. Median (IQR) time to recurrence was 24 (10–62) months. The 5-year overall survival was 74% and recurrence-free survival 70%. Conclusion Despite good overall survival, recurrence still occurred in 21% of patients. Most recurrences were distant, outside the radiation and surgical fields.