MP33-02: Primary Retroperitoneal Lymph Node Dissection for Metastatic Nonseminomatous Germ Cell Tumor: Review of Oncologic Outcomes and the Role of Adjuvant Chemotherapy
Introduction: There is renewed controversy regarding the role of adjuvant chemotherapy post primary retroperitoneal lymph node dissection (pRPLND) in the management of pathologic stage II (pN1-3) nonseminomatous germ cell tumours (NSGCT). We compared the outcomes and treatment burden of pRPLND alone versus pRPLND + adjuvant chemotherapy (AC) in this setting. Methods: Retrospective review of the Princess Margaret Cancer Center eTestes cancer database identified men with pathologic stage II NSGCT after pRPLND between 1995-2020. The primary outcome was relapse-free survival (RFS). Secondary outcomes included disease specific survival (DSS) and burden of relapse treatment. Uni- and multivariable analyses were conducted to identify factors associated with relapse. Results: A total of 109 pathologic stage II patients were included in the study. There were 96 patients treated with pRPLND alone and 13 treated with pRLND + AC (majority 2 cycles of Bleomycin, Etoposide, Cisplatin). Median follow up was 58 months. Of the 109 patients, 20 (18%) had pN1 and 89 (82%) had pN2/3 disease. The 5-year RFS was 72% for the pRPLND only group vs. 92% for the pRPLND + AC group (p=0.11). Within the pRPLND only group 5-year RFS differed by pN stage (pN1 = 94% vs. pN2/N3 = 67%, p=0.03). The presence of extra-nodal extension in the RPLND specimen was associated with relapse (HR 3.97, 95%CI 1.68-9.36, p=0.002). Despite a higher relapse rate within the pRPLND only group, DSS was similar at 5 years (98% pRPLND only vs. 100% pRPLND + AC, p=0.48). Only 24 (25%) of patients in the pRPLND only group required any chemotherapy. Extrapolating our outcomes to compare a hypothetical group of 100 patients treated with pRPLND alone to 100 with pRPLND + AC, the overall burden of chemotherapy was substantially higher in the pRPLND + AC arm (246 vs. 79 cycles). Conclusions: The majority of men with pathologic stage II NSGCT treated with pRPLND alone do not experience a recurrence or require systemic therapy. Despite a trend towards lower relapse risk when adjuvant chemotherapy is given, no difference in survival was seen but higher chemotherapy burden was entertained. Thus, AC for patients with pathologic stage II NSGCT may constitute overtreatment. SOURCE OF Funding: The Dell’Elce Family Testis Cancer Research Fund
