Influence of tumor response and treatment schedule on the distribution of tumor recurrence in esophageal cancer patients treated with neoadjuvant chemoradiotherapy

113 Background: Knowledge of pathologic complete tumor response (pCR) and the used neoadjuvant chemoradiotherapy (nCRT) schedule on the distribution of recurrent disease is important in the treatment of esophageal cancer (EC) patients. We assessed the effect of both pCR and different nCRT schedules on the pattern of first tumor recurrences in EC. Methods: The study was performed in two different centers in patients with T1N+/T2-4aN0-3/M0 EC. Patients were treated with nCRT according to the CROSS (carboplatin/paclitaxel/41.4Gy : n=134) and Cis/5FU schedule (Cisplatin/5-fluorouracil/45-50.4Gy : n=88) followed by surgery. First we determined the effect of pCR on tumor recurrence distribution (local, distant or combined) and site-specific recurrences in the CROSS group. After propensity matching on clinical T-stage, clinical N-stage and histology (n=63), we determined the effect of both nCRT schedules on the distribution of tumor recurrence and site specific recurrences. Results: The median follow-up after pCR (n=24) was significant longer ( P=0.001) than in non-complete responders (pNCR); 45.5 (IQR 20.3-69.5) and 20.0 months (12.0-42.3), respectively. The pattern of recurrence also differed significantly ( P=0.001), with 0 (0.0%) and 7 (6.4%) locoregional, 5 (20.8%) and 36 (32.7%) distant, and 0 (0.0%) and 21 (19.1%) local and distant recurrence between the pCR and pNCR group, respectively. Patients with a pCR had significant less local and distant recurrences. With equal median time to recurrence, the distribution of metastases in the matched groups differed only in the numbers of lung metastases ( P=0.029), with 15 (23.8%) and 6 (9.5%), respectively. Conclusions: Patients with a pCR have less local and distant recurrences. With equal time to first recurrence, the nCRT schedule itself had only a minor influence on the distribution of recurrences.