Residual tumor after the salvage surgery is the major risk factors for primary treatment failure in malignant ovarian germ cell tumors: A retrospective study of single institution

Background: Malignant ovarian germ cell tumors are rare, and knowledge of their prognostic factors is limited, with little available randomized data. This study was conducted to evaluate the clinicopathologic characteristics of malignant ovarian germ cell tumors and to determine the association of their prognostic factors to primary treatment failure. Methods: The medical records of 57 patients with stages I to IV malignant ovarian germ cell tumor were retrospectively reviewed, and their clinicopathologic and treatment-related data were collected and analyzed. Results: The median age at the diagnosis was 23.3 years (range: 8-65 years), and the median follow-up period was 108 months (range: 48-205 months). The histological types of the tumors were immature teratoma (n = 24), dysgerminoma (n = 20), endodermal sinus tumor (n = 8), mixed germ cell tumor (n = 4), and choriocarcinoma (n = 1). 66.7% of the patients had stage I disease; 5.2%, stage II; 26.3%, stage III; and 1.8%, stage IV. After the initial surgery, 49 patients (86%) received cisplatin-based chemotherapy. The five-year survival rate was 96.5%. There were six primary treatment failures, with two of the patients dying of the disease, and the median time to the recurrence was 8 months. The histological diagnosis (P < 0.0001), tumor stage (P = 0.0052), elevation of beta-hCG (P = 0.0134), operation methods (P = 0.0006), and residual tumor after the salvage surgery (P < 0.0001) were significantly associated with the risk of primary treatment failure in the univariate analysis. In the multivariate analysis, the residual tumor after the salvage surgery was the only significant variable associated with primary treatment failure (P = 0.0011, Hazard ratio = 29.046, 95% Confidence interval 3.832-220.181). Conclusion: Most malignant ovarian germ cell tumors have excellent prognoses with primary treatment, and good reproductive outcomes can be expected. Because primary treatment failure is associated with the residual disease after the salvage surgery, knowledge of the presence or absence of this risk factor may be helpful in risk stratification and individualization of adjuvant therapy in malignant ovarian germ cell tumors. Further large-scale prospective studies to confirm these results should be performed.