642 PL02.01 DOES A HIGH MANDARD SCORE REALLY DEFINE A POOR RESPONSE TO CHEMOTHERAPY IN OESOPHAGEAL ADENOCARCINOMA?

Abstract

Abstract A high Mandard score corresponds to a non-response to chemotherapy in the primary tumour in oesophageal adenocarcinoma. However, some patients experience tumour volume reduction and a nodal downstaging despite a high score. This study compares survival and recurrence patterns in these patients. Methods Clinicopathological factors were analysed using multivariable Cox regression assessing time to death and recurrence. CT estimated tumour volume change was examined in a subgroup of consecutive patients. Mean pre-chemotherapy and post chemotherapy tumour volumes were compared across Mandard groups and nodal responders. Results 555 patients were included. Median survival was 55 months (Mandard 1,2,3) and 21 months (Mandard 4,5). In the Mandard 4,5 group (332 patients), comparison between complete nodal responders and persistent nodal disease showed improved survival (90 vs 18 months), recurrence rates (locoregional 14.75% vs 28.74, systemic 24.59% vs 48.42%) and CRM positivity (22.95% vs 68.11). Complete nodal response independently predicted improved survival (HR 0.34(0.16–0.74). Post-chemotherapy tumour volume reduction was greater in patients with a complete nodal response (−16.3 cm3 vs −7.7 cm3 p 0.033) with no significant difference between Mandard groups. Conclusion: Patients with a complete nodal response to chemotherapy have significantly improved outcomes despite a poor Mandard score. High Mandard score does not correspond with a non-response to chemotherapy in all cases and patients with nodal downstaging may still benefit from adjuvant chemotherapy.