Second-line Chemotherapy of Platinum Compound plus CPT-11 Following ADOC Chemotherapy in Advanced Thymic Carcinoma: Analysis of Seven Cases

Background: Optimal chemotherapeutic regimen in thymic carcinoma remains uncertain and the efficacy of second line chemotherapy has not been established either. Patients and Methods: We retrospectively evaluated the efficacy of an irinotecan plus cisplatin or carboplatin (IP) regimen as a salvage treatment for patients with unresectable thymic carcinoma that progressed after cisplatin, doxorubicin, vincristine and cyclophosphamide (ADOC) chemotherapy. Seven patients with histologically confirmed thymic carcinoma that was resistant to or who had relapsed after initial chemotherapy with ADOC were treated with IP. The treatment consisted of irinotecan (CPT-11, 60 mg/m 2 , days 1, 8 and 15) and cisplatin (80 mg/m 2 , day 1) or carboplatin (AUC 4) intravenously every 4 weeks, for at least 2 cycles. Result: Two patients achieved partial responses. Although another two patients showed a significant reduction of the primary thoracic lesion, the appearance of a new lesion was found in one and a metastatic lesion was unchanged in the other. Neutropenia over grade 3 was observed in all patients but none of the patients developed serious infections. There were no severe non-hematological toxicities, including diarrhea. Conclusion: We conclude that salvage chemotherapy may be useful in certain patients with thymic carcinoma and irinotecan may be a novel and alternative agent for relapsed thymic carcinoma. Thymic carcinoma differs from thymoma not only morphologically but also biologically (1, 2). Thymic carcinoma is a thymic epithelial neoplasma with cytological malignant features and the clinical course tends to be much more aggressive than that of thymoma (3-5). Thymic carcinoma also tends to metastasize widely, showing a highly lethal course (3- 8). Thus, the role of systemic chemotherapy may be important in the treatment strategy for thymic carcinoma. Several reports demonstrated that combination chemotherapy, particularly a regimen containing cisplatin, was effective against thymic carcinoma (6-11). Among these reports, Yoh et al. (7) evaluated the efficacy of CODE (cisplatin, vincristine, doxorubicin and etoposide) therapy for thymic carcinoma and reported a response rate of 42%. Kitami et al. (8) and our group (9) reported 57% (4 out of 7 cases) and 75% (6 out of 8 cases) response rates respectively with cisplatin, doxorubicin, vincristine and cyclophosphamide (ADOC) chemotherapy. Thus, thymic carcinoma is a chemosensitive tumor. However, there is no information about second-line chemotherapy in advanced thymic carcinoma. We described seven cases of unresectable thymic carcinoma treated with irinotecan plus platinum compound (cisplatin or carboplatin) (IP) as second line chemotherapy after relapse following ADOC chemotherapy. We analyzed the efficacy of chemotherapy and discuss the role of second line chemotherapy in thymic carcinoma.