Long term outcomes of Dynamic Sentinel Lymph Node Biopsy (DSNB) for clinically impalpable (cN0) penile cancer patients- an eUROGEN study

Abstract

Introduction & Objectives: Dynamic Sentinel Lymph Node Biopsy (DSNB) is routinely offered to patients presenting with penile cancer ³T1G2 and clinically impalpable inguinal lymph nodes (cN0). We aimed to assess the diagnostic accuracy of DSNB, Cancer Specific Survival (CSS) in patients with positive DSNB and positive LN at further Radical Lymph Node groin Dissection (RLND). Materials & Methods: An eUROGEN retrospective study of 509 penile cancer patients undergoing DSNB. Age, type of primary surgery, complications after DSNB, tumour stage, tumour grade were all reported. Number of true positives, true negatives, false negatives and false positives were recorded. False negative was defined as inguinal lymph node recurrence within 12 months from a previous negative DSNB. Sensitivity and specificity of DSNB were calculated. Kaplan-Meier analysis was used to estimate the 5-years CSS and recurrence free-survival rates among patients with positive DNSB and RLND. Results: Overall, 509 patients with cN0 penile cancer were identified. The median follow-up for local recurrence and CSS were 62.5 months (IQR 28.5-91) and 63.5 months (IQR 26.5-90) respectively. All patients underwent DSNB at the time of primary surgery or as a delayed procedure. A total of 993 groins were studied. 37 patients had positive histology at DSNB. 37 patients underwent further RLND with 34 of them having positive histology at RLND. At DSNB true positives were 37 (7.27%), false negatives 3 (0.59). Sensitivity and specificity were 92.5% and 100% respectively. Multivariable Cox regression analysis identified positive LN histology both at DSNB and at RLND as predictors for reduced CSS (HR 4.59, CI: 2.35-8.95, p<0.0001) and (HR 5.64, p=0.0004). Likewise, positive LN histology at DSNB and RLND was a predictor for reduced recurrence free survival HR 4.04 and HR 6.98 all p<0.0001. At Kaplan-Meier analysis, the 5-years CSS for positive LN histology at DSNB/RLND were 69.7% and 69.6% respectively.