Radiological evaluation of different retroperitoneal lymph node measurements in stage 1 testicular cancer patients: influence on clinical stage and therapy

Abstract

Purpose To investigate current inconsistent guideline recommendations for the initial staging of retroperitoneal lymph node metastasis in testicular germ cell tumor (GCT) patients and their influence on clinical stage (cS) and therapy.Methods 154 cSI GCT patients who underwent orchiectomy without any adjuvant therapy and a follow-up ≥ 24 months were retrospectively examined. cSI was defined as retroperitoneal lymph nodes < 10mm in axial short-axis diameter (SAD). Retroperitoneal lymph nodes were measured in staging imaging, considering the different dimensions (SAD and long-axis diameter (LAD)) in the three different radiological planes: axial, sagittal and coronal.Results Overall survival (OS) was 100%, 82% were free of recurrence, with a median follow-up of 83 months. By using axial SAD (RECIST 1.1), all patients were classified as cSI. Based on axial LAD (SWENOTECA, German S3 guideline) or maximum LAD in any plane (EAU, ESMO, onkopedia and AJCC), significantly more patients would be classified as cSIIA (0% vs. 38% vs. 52%) or even cSIIB (0% vs. 1% vs. 25%); p < 0.001. Overtreatment would occur in 0%, 31% and 61% for axial SAD, axial LAD and maximum LAD, while undertreatment would affect 18%, 10% and 2%, respectively (p < 0.001).Conclusion We found a huge variety of cS based on different lymph node staging recommendations in current guidelines. With 100% OS in the entire cohort and balancing risks of overtreatment and undertreatment, with stage-adapted treatment at relapse, a prospective multicenter study should investigate whether using axial SAD according to RECIST 1.1 could be the supposed best parameter to standardize guideline recommendations.