514P Nerve sparing retroperitoneal lymph node dissection for clinical stage IIA/B seminomas: A clinical phase II trial

Abstract

Retroperitoneal radiation therapy or systemic chemotherapy with 3 cycles PEB represent the guideline recommended treatment options in marker negative clinical stage IIA/B seminoma. Despite a high cure rate of 90% to 94% and 82% to 90% in CS IIA and IIB, respectively, both therapeutic options are associated with significant long-term toxicities. It was the aim of our trial to evaluate the feasibility, oncological efficacy and treatment associated morbidity of primary nsRPLND in stage IIA/B seminoma. 21 patients with marker negative clinical stage IIA and IIB classical seminoma of the testis were recruited in the prospective trial. Exclusion criteria were adjuvant carboplatin therapy for clinical stage I disease, extensive clinical stage IIb or clinical stage IIc, previous retroperitoneal surgery or radiation therapy, positive tumor markers. Mean age was 37.8 (21-54) years. Mean follow-up is 20.1 (1-48) months and 26 (3-48) for those with a minimum follow-up of 3 months. All patients were treatment-naïve; 9 and 12 patients presented in stage IIA/B at time of primary diagnosis or during active surveillance for clinical stage I disease, respectively. 13 and 8 patients were diagnosed with stage IIA and IIB disease, respectively. 19 and 2 patients underwent open and robot assisted ns RPLND, respectively. Mean OR time was 131 (105-195) min, mean blood loss was < 150ml and the mean hospitalization time was 4.5 (3-9) days. We did not observe surgery associated complications > Clavien Dindo grade 3a. Mean number of dissected lymph nodes was 17 (7-57), the mean number of positive lymph nodes was 1 (1-2) and the mean diameter of positive nodes was 2.1 (0.8-4.1) cm. Histology of the resected lymph nodes revealed metastatic seminoma in 17 (80.9%) patients; 1 and 3 patients demonstrated embryonal carcinoma and benign disease, resp. 2/21 (9.5%) patients developed an outfield relapse 4 and 6 months postoperatively. Both patients were salvaged by systemic chemotherapy with 4 cycles PEB. NsRPLND results in a high cure rate at midterm follow-up and it is associated with a low frequency of treatment associated morbidities making this approach a feasible alternative to standard radiation therapy or systemic chemotherapy.