Outcome of Postchemotherapy Residual Disease in Extracranial Germ Cell Tumor in Children: Experience of a Tertiary Care Center.

Abstract

The aim was to review outcome with residual disease at the end of first line chemotherapy in patients with extracranial germ cell tumor (GCT) in our resource limited setting. A retrospective analysis of 196 patients with GCT recruited at Shaukat Khanum Memorial Cancer Hospital (SKMCH) from January 2008 to December 2016. Data fields included site, histopathology, stage, risk groups, baseline alpha fetoprotein, beta human chorionic gonadotropin levels, residuum after primary treatment, completeness of surgical excision and outcomes. Data analysis involved quantitative analysis, mean and median calculations, event free survival (EFS) and overall survival (OS) calculations using Kaplan-Meier curves. In 196 included patients, M:F ratio was 1. There were 81 (41.3%) adolescents. Alpha fetoprotein was >10,000 IU/L in 56 (28.6%) patients. Sixty-two (31.6%) patients had extragonadal disease. Most patients (n=137, 69.9%) presented with advanced stage (III/IV). Seventy-six patients had postchemotherapy residual disease (n=59 [78%] with partial response (PR) and 17 [22%] with no response [NR]). Five-year OS was 83% and EFS was 67%. Five-year EFS of patients with complete remission after primary chemotherapy was 85% versus 70% in patients with PR and 6% in those with NR (P=0.001). OS in patients with complete remission, PR and NR was 94%, 87%, and 46%, respectively. All patients with NR progressed or relapsed and 8/17 died. Four patients with normalized tumor marker response were found to have active tumor on resection of postchemotherapy residuum. Patients with postchemotherapy residual disease in pediatric extracranial GCTs, fare better if their residuum is resected compared with those who do not undergo resection.