The optimal chemotherapeutic regimen for cancer of unknown primary (CUP) remains uncertain. We encountered 3 cases with CUP who presented with thoracic lymph node metastasis. Detailed physical examination and diagnostic tests, including laboratory investigations, bronchoscopy, upper and lower gastrointestinal studies, computed tomography of the head, neck, abdomen and pelvis and ¹⁸F-fluorodeoxyglucose positron emission tomography, failed to identify the primary site in these cases. The patients were treated with the cisplatin plus docetaxel chemotherapy regimen. Concomitant thoracic radiotherapy was conducted in one patient and surgical resection in another. All patients showed good response to the chemotherapy and achieved long-term disease-free survival.

The optimal second-line chemotherapeutic regimen for thymic carcinoma remains uncertain and predictive factors for the response have not been identified. We encountered two cases of relapsed thymic carcinoma with recurrence 1.5 and 8 years after initial response to cisplatin/doxorubicin/vincristine/cyclophosphamide (ADOC) chemotherapy. Both cases were successfully retreated with ADOC. Our observations suggest that relapsed thymic carcinoma occurring a long treatment-free time from the initial response may be sensitive to the previous chemotherapy. We described two cases of relapsed thymic carcinoma successfully retreated with ADOC chemotherapy. Both patients had partial response to initial ADOC and long disease free times.