Since the outcome of patients with esophageal cancer treated with neoadjuvant chemoradiation and surgery is still poor, strategies to improve survival should be explored. The benefit of adjuvant chemotherapy after neoadjuvant chemoradiotherapy followed by surgery is unknown. Preferably, such adjuvant chemotherapy regimen should consist of a non-cross resistant, well-tolerated schedule. For this purpose, the combination of S-1, an oral fluoropyrimidine, with oxaliplatin, may be of benefit, as each of these compounds have shown efficacy in gastroesophageal cancer. Also, importantly, the combination of S-1 with oxaliplatin (SOX) in advanced gastric cancer was well-tolerated. Nevertheless, it should be acknowledged that after major surgery for esophageal cancer, adjuvant treatment with combination chemotherapy may be hard to accomplish as was shown in the MAGIC trial for gastric cancer where less than half of all patients completed adjuvant therapy.~Therefore the investigators want to assess the feasibility of an adjuvant treatment scheme with S-1 and Oxaliplatin. When the proposed treatment scheme is feasible the potential benefit on survival will be evaluated in further studies. Feasibility is defined ≥50% of patients completing the pre-planned number of cycles~Study Objectives Primary Objective To assess the feasibility of administering adjuvant SOX in patients with esophageal cancer after neoadjuvant chemoradiotherapy with paclitaxel and carboplatin and esophagectomy~Secondary Objectives~Percentage of patients completing 6 cycles of S-1 (with or without oxaliplatin).~Dose modifications (ie, delays, dose reductions, or interruptions) for S-1.~Dose modifications (ie, delays, dose reductions, or interruptions) for oxaliplatin.~Dose intensity of S-1.~Dose intensity of oxaliplatin.~Toxicity.~Disease free survival.~Exploratory Objectives~Assessment of pharmacokinetics of S1 as predictive factors for efficacy and toxicity.~Potential biomarker development based on assessment of archived tumor tissue and blood samples and the proposed mechanism of action of study drugs.
In this prospective single arm study the investigators will assess the feasibility of S-1 and Oxaliplatin as adjuvant treatment in patients with esophageal cancer.~The primary objective is to assess the feasibility of administering adjuvant S-1 and Oxaliplatin (SOX) in patients with esophageal cancer after neoadjuvant chemoradiotherapy with paclitaxel and carboplatin and esophagectomy. Primary end point is the percentage of patients completing the preplanned number of 6 cycles of SOX.