Predicting outcomes in malignant ovarian germ cell tumors using the modified International Germ Cell Cancer Collaborative Group classification system

Objectives The aim of our study was to evaluate the feasibility of the modified International Germ Cell Cancer Collaborative Group risk classification system in Chinese female patients with malignant ovarian germ cell tumors and to identify predictive factors to enhance the risk classification system. Methods In this retrospective cohort analysis, patients with malignant ovarian germ cell tumors who received surgery with/without chemotherapy were included. These patients had been followed-up by Peking Union Medical College Hospital between 2011 to 2020. Patients without complete medical records or no follow-up information were excluded. Results The study enrolled a total of 271 patients. The risk model classified 106 (39.1%) patients as good-, 84 (31%) as intermediate-, and 81 (29.9%) as poor-risk. With a median follow-up time of 34 months (range 2-147), 48 (17.7%) recurrence and 16 (5.9%) deaths were observed. The risk classification significantly correlated with 3 year disease-free survival and overall survival (log rank p<0.001 and p=0.003, respectively). The survival outcomes of disease-free survival and overall survival were not statistically different among risk groups in patients who received neoadjuvant chemotherapy (log rank p=0.77 and 0.41, respectively). Univariate and multivariable analysis showed that tumor stage (p=0.033, hazard ratio (HR) 2.05, 95% confidence interval (CI) 1.06 to 3.96) was significantly associated with relapse or progression of disease. Patients over age 40 years exhibited a poor prognosis. Conclusion The modified International Germ Cell Cancer Collaborative Group risk classification system was efficacious in patients with malignant ovarian germ cell tumors and was significantly associated with disease-free survival and overall survival. Risk assessment after neoadjuvant chemotherapy may be more predictive than stratification at initial diagnosis. Age and tumor stage were definitive prognostic factors for germ cell tumors, which may need to be incorporated in the stratification system.