[Observation policy for residual masses after chemotherapy for gonadal and extra-gonadal germ cell tumors].

Twenty-five patients with germ cell tumors who had marker-free residual masses after undergoing chemotherapy were followed for up to 10 years (median, 21 months). The primary tumor sites were the gonads in 20 patients (6 seminomas [SGCTs] and 14 non-seminomatous germ cell tumors [NSGCTs]) and extra-gonadal regions in 5 patients (5 NSGCTs). All residual masses were observed in patients with SGCT. Residual masses that were 2 cm or less in size were left unresected, while masses that were 5 cm or more in size were resected in patients with NSGCT lesions. The management of other residual masses was decided based on the size, shrinkage, and pathological findings of the tumors. Residual masses were resected in six of the patients with gonadal NSGCTs. Recurrence occurred in one of the six patients with gonadal SGCTs (chemotherapy shrinkage; 11 cm to 3.5 cm) and three of the four cases with extra-gonadal NSGCTs (embryonal cell carcinoma: 3 cm to 1 cm, embryonal cell carcinoma+york sac tumor: 5 cm to 4 cm, embryonal cell carcinoma+chorio carcinoma; 4 cm to 1.2 cm). None of the patients with gonadal NSGCTs experienced a recurrence. Considering the pathologic diagnosis, shrinkage, and international germ cell consensus classification, unnecessary resections of residual masses that were less than 5 cm in size after chemotherapy for gonadal NSGCT should be avoided. However, residual masses in extra-gonadal NSGCTs should be resected.