Disease characteristics and survival outcomes of extragonadal primary germ cell tumour in two Canadian tertiary cancer centres.

INTRODUCTION: Extragonadal germ cell tumours (EGCTs) are a heterogeneous group with distinct natural history and responses to treatment modalities. We sought to evaluate characteristics and survival outcomes in men with EGCTs.

METHODS: We performed a retrospective analysis on a consecutive list of men diagnosed with EGCT in two Albertan cancer centres between 1990 and 2013. Demographic characteristics and outcomes, stratified by primary site, were evaluated.

RESULTS: Sixty-nine cases were identified. The median age was 29 (range 15-76) and 48 cases (70%) were non-seminomatous. Twenty-four (35%) belonged to International Germ Cell Cancer Collaborative Group (IGCCCG) favourable risk group, 14 (20%) to intermediate, and 31 (45%) to poor. Thirty (43%) had mediastinal primary (MPs); 29 were treated with first-line bleomycin, etopo-side, and cisplatin (BEP). Seventeen (57%) relapses occurred, of which three patients achieved long-term survival. Seventeen (25%) had a central nervous system (CNS) primary, with eight (47%) classic germinoma. Seven (41%) received primary chemotherapy alone; 5 (29%) received primary radiotherapy alone, and 5 (29%) received both. Nineteen (28%) had a retroperitoneal primary (RPs) and received first-line chemotherapy; all but two received BEP and eight (42%) had surgical resection. Three (5%) had other or unknown primary. Five-year overall survival (OS) and disease-free survival for all patients were 56% and 44%, respectively; for MPs, 44% and 34%; for CNS primary, 76% and 53%; for RPs, 58% and 53%. Factors that correlated with decreased OS were elevated alpha fetoprotein (AFP) (p<0.001) or human chorionic gonadotropin (HCG) (p=0.001), lactate dehydrogenase (LDH) levels (p=0.028), bone metastasis (p<0.001), lung metastasis (p<0.001), and IGCCCG poor risk (p=0.001).

CONCLUSIONS: EGCT is a rare, but important subset of GCT. Patients with EGCTs, despite aggressive treatments, still have poorer outcomes than gonadal primary.