Oncologic outcomes of retroperitoneal lymph node dissection following first-line chemotherapy for metastatic non-seminomatous germ-cell tumors.

Background: Post-chemotherapy retroperitoneal lymph node dissection (pcRPLND) is integral to multimodal treatment of patients with metastatic non-seminomatous germ-cell tumors (NSGCT). We review pathologic and long-term outcomes of pcRPLND following first-line chemotherapy with a focus on residual mass size and primary tumor histology. Our goal was to identify new predictive approaches that can refine surgical indications.

Methods: Patients who underwent pcRPLND for NSGCT at our institution between 1 January 2000 and 18 January 2023 following first-line chemotherapy were included. The primary outcome was surgical pathology categorized as (i) viable non-teratomatous germ-cell tumor (GCT) (with or without teratoma), (ii) teratoma only, or (iii) fibrosis/necrosis stratified by largest residual mass size. Secondary outcomes included 10-year relapse-free survival, disease-specific survival, and overall survival.

Results: Of 1027 eligible patients, 45% had teratoma and 4% had viable non-teratomatous GCT found at pcRPLND. With a median follow-up of 5.2 years, there was one isolated retroperitoneal relapse and 26 GCT-related deaths. As the residual mass size increased, the likelihood of teratoma in the pcRPLND specimen increased from ∼20% (residual masses <1 cm) to ∼70% (>5 cm). The risk of viable non-teratomatous GCT similarly increased from ∼2% up to ∼10%. Ten-year relapse-free and overall survival worsened with increasing mass size. Adjusting for risk group, clinical stage, residual mass size, and lymphovascular invasion at orchiectomy, the presence of yolk sac tumor [odds ratio (OR) 1.86, 95% confidence interval (CI) 1.35-2.56] and teratoma in the orchiectomy specimen (OR 3.09, 95% CI 2.27-4.23) were each independently associated with finding teratoma or viable non-teratomatous GCT at pcRPLND.

Conclusions: Following first-line chemotherapy, pcRPLND provides effective control of the retroperitoneum with few relapses and GCT-related deaths. Guideline recommendations for or against pcRPLND based on residual mass size alone should be revisited due to the significant association of orchiectomy histology with pcRPLND pathology and the benefits surgical consolidation has on disease control and survival.