Induction Chemoradiotherapy Followed by Resection for Locally Advanced Masaoka Stage III and IVA Thymic Tumors

Background The treatment of locally advanced thymic tumors is not uniform. Recently, several centers have reported the results of induction chemotherapy followed by resection and then radiation. Our center adopted an alternative strategy and treated locally advanced thymic tumors with induction chemoradiotherapy in an effort to maximize the intensity of the induction therapy. Methods A retrospective review was performed of 10 patients with locally advanced thymic tumors treated from 1997 to 2006. Seven patients were clinically staged as Masaoka stage III and 3 as stage IVA. The treatment plan included two cycles of cisplatin and etoposide with concurrent radiation. Patients then had resection followed by postoperative chemotherapy if they were judged to be at high risk for relapse. Results Four patients had a partial radiographic response to induction therapy and 6 had no response. Eight patients had a R0 resection and 2 had a R1 resection. Four patients had substantial (>90%) necrosis in the resected specimen. There was no postoperative mortality. Seven patients had two more cycles of chemotherapy. The median follow-up was 41 months. Three patients had recurrences. The 5-year estimated survival was 69% (95% confidence interval: 32% to 100%). Conclusions Induction therapy for locally advanced thymic tumors with cisplatin, etoposide, and radiation is well tolerated, with many patients having a partial radiographic response. The majority of patients can undergo a complete resection with this treatment. The survival of these patients compares favorably with those undergoing other induction regimens. Further efforts to maximize the intensity of induction therapy for locally advanced thymic tumors is warranted. We have initiated a multicenter phase 2 clinical trial (NCT00387868) to prospectively test this concept.