Clinical characteristics and outcomes of patients with primary mediastinal germ cell tumors.

Abstract

389 Background: Mediastinal germ cell tumors (MGCTs) account for 20% of all mediastinal tumors. Cisplatin-based chemotherapy followed by surgical resection of residual tumor remains the standard of care. To prevent pulmonary complications secondary to extensive thoracic surgery, non-bleomycin containing regimen is generally preferred. This study aims to review clinical characteristics and outcomes of these patients. Methods: A retrospective chart review was undertaken in patients with MGCTs treated in our institution between 1993 and 2013. Results: A total of 40 patients were enrolled with a median age of 24. Only one patient is female. Stratified by histology; eight patients (20%) had pure seminoma, 25 patients (62.5%) had pure non-seminoma, four patients (10%) had mixed seminoma and non-seminoma, and three patients (7.5%) had malignant transformation (two adenocarcinoma, one sarcoma). Median tumor size was 13 centimeters. Ninety-two percent of patients received chemotherapy as a first treatment modality, whereas 8% underwent upfront surgery. All patients received cisplatin-based chemotherapy: Eighty seven percent bleomycin, etoposide and cisplatin; 13% etoposide and cisplatin. Seventy-two percent of patients completed four planned cycles of chemotherapy. Thirty-one patients were able to assess radiological response: 3.2% complete response, 58.1% partial response, 29.0% stable disease, and 9.7% progressive disease. Forty-four percent of patients achieved completely serological response with chemotherapy. Seventeen patients underwent surgical resection of residual tumor. Among these, viable tumor was seen in 35% (6 out of 17 patients). No patients complicated with clinically significant pulmonary complications after thoracic surgery. The five year overall survival (OS) of patients with seminoma was 72.9% as compared with 19.9% in those with non-seminoma (p=0.012). For those who received chemotherapy followed by surgical resection with no viable tumor or only mature teratoma detected (N=11), the five year OS was 64.9%. Conclusions: Our study confirmed the importance of multi-modality approaches with primary chemotherapy followed by surgical resection of residual tumor. Bleomycin-containing regimen can be safely used in this setting.