Key Therapeutic Agents for Thymic Carcinoma in Real-world Clinical Practice

Thymic carcinoma is a rare cancer with poor prognosis in unresectable cases. Treatment efficacy of carboplatin+paclitaxel (CP), lenvatinib, S-1, and sunitinib remains uncertain, with some patients experiencing increased post-treatment liver metastasis.

We performed a retrospective analysis of patients with metastatic thymic carcinoma who received chemotherapy between 2006 and 2023 at the National Cancer Center Hospital. We evaluated the clinical outcomes [progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), liver metastasis response rate (LMRR), and liver metastasis control rate (LMCR)] of CP, lenvatinib, S-1, and sunitinib.

A total of 178 patients were evaluated, with 78.1% having stage IV disease. Most patients had squamous cell carcinoma (85.4%), and 39 patients had liver metastases (21.9%). The most frequently administered treatments as 1^st-, 2^nd-, and 3^rd- line were CP (85.5%), S-1 (58.3%), and sunitinib (28.4%). The median PFS was 6.8, 9.4, 4.5, and 3.4 months in CP, lenvatinib, S-1, and sunitinib. CP showed an ORR of 41.6% and LMRR of 40.9%. The reverse response, in which only liver metastasis increased despite shrinkage of other lesions, was observed in lenvatinib (20%), S-1 (3.4%), and sunitinib (8.3%).

CP and lenvatinib provided effective outcomes in metastatic thymic carcinoma, aligning with previous findings. S-1 and sunitinib also show clinical activity but with variable responses in liver metastases. These results highlight the importance of tailored treatment strategies, particularly for patients with liver involvement.