Conversion Surgery for Thoracic Esophageal Cancer

Abstract Background Definitive chemoradiotherapy (dCRT) is an important treatment option for esophageal cancer. At our hospital, dCRT is the first-line treatment for cT4b, and DCF therapy is the first-line treatment for cT3br. We also actively perform immunotherapy (ICI) + cisplatin +5-FU therapy as primary treatment for unresectable advanced esophageal cancer with distant lymph node metastasis, etc. In this study, we investigated the techniques, prognosis and postoperative complications of conversion surgery after the above-mentioned dCRT, DCF therapy and ICI therapy. We also investigated the possibility of organ preservation through ICI induction chemotherapy, with the aim of obtaining findings on curability and safety. Methods The study was conducted from April 2012 to September 2024, and included 54 cases of conversion surgery for cT3br and cT4b thoracic esophageal cancer (cT3br: 28 cases, cT4b: 26 cases). The organs involved (including suspected involvement) were the trachea and left main bronchus in 31 cases, the aorta in 18 cases, and other organs in 5 cases. The treatment outcomes, complications, and recurrence were retrospectively examined. ICI + cisplatin +5-FU therapy was administered to 71 cases, and conversion surgery was performed in 8 cases (11%) of them. Results 43 cases underwent thoracoscopic esophagectomy,1 case underwent robot-assisted surgery. Postoperative complications (Clavien-Dindo Grade II or higher) were observed in 24 cases (44%). The median recurrence-free survival period was 18 months. The 3-year overall survival rate was 60% for cT3br and 50% for cT4b. The prognosis was poor in cases with residual cancer, aortic invasion, or preoperative lymph node metastasis. Of the 8 cases of conversion surgery after ICI, 7 were thoracoscopic esophagectomy and 1 was robot-assisted surgery. Although radical resection was possible in all cases, postoperative recurrence was observed in 3 cases, and the overall survival was 12.9 (3.4–18.6) months. Conclusion Each treatment method has a high probability of achieving down staging, and the results after surgery are also relatively good, so we think that the choice of treatment is appropriate. However, the prognosis is poor in cases of aortic invasion and lymph node metastasis, so it is necessary to establish multidisciplinary treatment centered on postoperative adjuvant therapy. There is no significant difference in safety between surgery after ICI use and other conversion surgeries, and there is a possibility of cure even in cases where radical treatment was not possible in the past, so it is necessary to create evidence.