Aggressive surgical management of germ cell tumors with somatic-type malignancy: Pathologic features, prognostic factors, and survival outcomes.

Abstract

4554 Background: Germ cell tumors (GCT) with somatic-type malignancy (SM) are rare occurring in approximately 3-8% of GCT cases. Prognostic factors and optimal management remain poorly-defined. Methods: The Indiana University (IU) testis cancer database was queried from 1979 to 2011 for patients demonstrating atypical histology at orchiectomy or subsequent resection of metastatic disease. Patients with transformation to PNET only were excluded due to distinct management. Chart review, pathologic review, and survival analysis were performed. Results: 122 patients met study inclusion criteria. Primary tumor site was testis in 112, retroperitoneum in 8, groin in 1, and pineal gland in 1. The most common SM histologies were sarcoma (71) and carcinoma (32). At GCT diagnosis, 24, 44, 45 patients had stage I, II, and III disease, respectively. Stage was unknown in 9. Median time from GCT diagnosis to SM was 13 months (Range, 0-397). This interval was longest for carcinomas (94.5 months) and sarcomatoid yolk sac tumors (113 months). Only 11 of 83 patients (13.3%) receiving cisplatin-based chemotherapy for measurable disease demonstrated an initial complete response. First resection at IU was reoperative in 45 patients (36.9%). 69 patients (56.6%) required extirpation of abdominal viscera/vascular structures or distant metastases. At a median follow-up of 71 months, the 5-year cancer specific survival (CSS) was 63%. Predictors of poorer CSS included SM diagnosed at late relapse (p = 0.014), referral to IU for reoperative RPLND (p = 0.022), and tumor grade (p = 0.043). SM histology subtype, stage, risk category, and number of resections for SM were not predictive of CSS. Conclusions: GCT with SM is associated with poorer CSS than traditional GCT. Established prognostic factors for GCT lose their predictive value in the setting of SM. SM can occur at any point in the course of GCT, but has a propensity for delayed presentation with later onset being associated with poorer CSS. Aggressive and serial surgical resections are often necessary to optimize CSS. Tumor grade is an important prognostic factor, particularly in sarcoma cases.