Multimodal treatment of children with sacrococcygeal yolk sac tumor: retrospective analysis of clinicopathology characteristics and relapse-free survival

Abstract

The aim of the study was to explore the clinicopathological characteristics of sacrococcygeal yolk sac tumor (SYST) associated with relapse. Methods: We collected clinical data regarding patients aged <18 years with SYST treated at Sun Yat-sen University Cancer Center between 2007 and 2018. We investigated prognostic factors of age, stage, initial tumor size, pathological response to neoadjuvant chemotherapy and alfa fetoprotein (AFP) in univariate and multivariate analysis. The Kaplan-Meier method was used to estimate the relapse-free survival (RFS). Results: We enrolled 26 patients with SYST (median age 1.7 years; range, 2 months to 5 years). Patients with predominance of female had elevated AFP at diagnosis (median 50,480 ng/ml, range 1,200-80,300,000). Twelve patients were stage IV. Neoadjuvant chemotherapy was administered to 20 cases. Six patients underwent resection as initial therapy. Resected tumor size at upfront resection was measured < 4.0cm × 3.0cm. No patient died of disease at last follow-up. Relapse occurred in 12 patients. Patients with specimen exhibiting no malignant component after chemotherapy didn't experience recurrence. Frequencies of recurrence were once in 5 patients, 3 in 2 patients, 2 in 3 patients, 4 in 1 patient and 6 in 1 patient, respectively. All relapsed patients still achieved partial remission (PR) or complete remission (CR) after salvage therapy. The cohort reached a 5-year RFS of 55.2% (median follow-up 59.5 months; range, 16-155). Univariate analysis identified sex as a significant prognostic factor of RFS (P = 0.02). In multivariate Cox regression, no variables had statistically significance. Patients with > 2 factors (boy, initial tumor size > 4cm×3cm, AFP > 60,000 ng/ml and poor pathological response) had poor RFS. Conclusion: Sex is a predictive factor of RFS in SYST. Girls with smaller initial tumor size, lower AFP and good pathological response have better RFS. Salvage chemotherapy can benefit patients.