Diagnostic Accuracy of Dynamic Sentinel Lymph Node Biopsy for Penile Cancer: A Systematic Review and Meta-analysis

Context: A dynamic sentinel lymph node biopsy (DSNB) is used for inguinal lymph node staging in patients presenting with primary penile cancer with clinically impalpable inguinal lymph nodes (cN0). Further completion radical inguinal lymph node dissection (RLND) is offered to patients diagnosed with metastatic inguinal nodes following a DSNB. Objective: To identify the diagnostic accuracy of a DSNB and RLND to detect lymph node metastasis. Evidence acquisition: A systematic literature search was performed on PubMed Medscape, EMBASE, Google Scholar, and Cochrane database for relevant studies between January 1, 2000 and April 30, 2022. Studies were included if a DSNB was offered to cN0 patients and if RLND was offered to patients with positive histology at the DSNB. Risk of bias and confounding assessments were performed. Diagnostic odds ratio, pooled sensitivity/specificity, and heterogeneity analyses were displayed. Evidence synthesis: Overall, 2893 patients in the 28 studies analysed underwent a DSNB. Twenty-one studies reported patients undergoing RLND for a positive DSNB. A DSNB showed pooled weighted sensitivity of 0.87 (95% confidence interval [CI]: 0.82-0.91) and pooled log diagnostic odds ratio of 6.17 (95% CI: 5.47-6.87). A DSNB showed pooled weighted sensitivity of 0.50 (95% CI: 0.24-0.59), specificity of 0.82 (95% CI: 0.78-0.87), and a log diagnostic odds ratio of 1.18 (95% CI: 0.29-2.97) for detecting further positive lymph nodes at RLND. High heterogeneity, mostly caused by study design, characteristics of the included patients, DSNB technique used, surgical experience/centre case volumes, and follow-up schedule, represents the main limitation of this meta-analysis. Several sensitivity analyses to address these issues support our findings. Conclusions: A positive DSNB is poorly able to discriminate which patients will have further metastatic involvement at completion RLND. Better stratification of these patients would avoid unnecessary overtreatment and possible postoperative comorbidities. Patient summary: This analysis of the data from the published literature provides evidence that the diagnostic accuracy of a dynamic sentinel lymph node biopsy (DSNB) requires further improvement. Moreover, a high proportion of patients with a positive DSNB undergo unnecessary radical lymph node dissection; better stratification of these patients might help determine avoidable overtreatment and postoperative comorbidities.