796 OUTCOMES OF DELAYED SURGERY IN PATIENTS WITH RESIDUAL DISEASE AFTER NEOADJUVANT CHEMORADIOTHERAPY FOR OESOPHAGEAL CANCER Free

Standard treatment for locally advanced oesophageal cancer is neoadjuvant chemoradiotherapy (nCRT), plus surgery 6-8 weeks later. Time to surgery (TTS) after nCRT seems safe up to 12 weeks, and possibly improves patient condition and pathological response. However, it is unknown whether prolonged TTS is safe in patients with residual disease. The aim of this study was to investigate whether prolonged TTS leads to inferior surgical outcomes and survival in patients with residual disease after nCRT.

Patients with pathologically confirmed residual disease 4-6 weeks after nCRT who underwent preoperative PET/CT and surgery were selected from the preSANO-trial and SANO-trial. Patients were stratified by TTS ≤12 weeks versus TTS >12 weeks after completion of nCRT. Primary endpoint was overall survival (OS). Secondary endpoints were progression-free survival (PFS), peroperative unresectability, microscopically radical resections (R0), tumour regression grade (TRG), postoperative complications and risk of distant dissemination. Effects of TTS on OS, PFS and distant dissemination were analysed with Cox regression, adjusted for Charlson comorbidity index (CCI) at baseline, as well as WHO performance score and weight loss after nCRT.

Forty-two patients were included in the TTS >12 weeks and 132 patients in the TTS ≤12 weeks group. Median follow-up was 20.6 months (IQR 16.1-30.3). Adjusted hazard ratios for OS and PFS were 0.50 (95% CI: 0.24-1.02) and 0.47 (95% CI: 0.25-0.91), respectively, in favour of TTS >12 weeks. Patients with TTS >12 weeks had more postoperative complications (89% vs 72%, p = 0.049), but comparable peroperatively unresectable tumours (11.9% vs. 3.8%, p = 0.11), R0-resections (89% vs 87%, p = 0.89), and TRG-scores (p = 0.97) compared to patients with TTS ≤12 weeks. Patients with TTS >12 weeks showed less distant dissemination (HR 0.40, 95% CI: 0.18-0.88).

Prolonged TTS beyond 12 weeks in patients with clinically proven residual disease after nCRT did not have a negative effect on OS and on PFS, but was correlated with an increase in postoperative complications. The (non-significantly) better survival outcomes for TTS >12 weeks may be explained by the fact that patients had a lower risk of developing distant dissemination, which may reflect improved selection prior to surgery.