Objectives: To evaluate the usage of surgical staging of inguinal lymph nodes (SSILNs) in the United States for intermediate to high-risk, clinically localized penile squamous cell cancer (SCC), to explore patient and hospital factors associated with omission of this staging, and to evaluate the effect on survival.
Patients and methods: Retrospective, observational study using the National Cancer Database from 2004 to 2014 of 1,689 men diagnosed with pT1b-T3, cN0 penile SCC, who by current guidelines should receive SSILNs-either by inguinal lymph node (ILN) dissection or sentinel node biopsy. Binomial logistic regression analysis was performed to determine predictors of SSILNs. Multivariate Cox regression analysis was performed to determine the impact of SSILNs on survival in the overall and propensity-score matched patient populations.
Results: Only 25.3% of patients underwent SSILNs. Increasing patient age, higher comorbidity status, lower pathologic stage, Medicaid insurance, and treatment at a nonacademic facility were independent factors associated with the omission of SSILNs. Omission of SSILNs was an independent predictor of overall mortality, both in the overall patient population after multivariate adjustment, HR = 1.46 [(95% CI: 1.14-1.88), P = 0.003], and in the propensity-score matched adjusted population, HR = 1.59 [(95% CI: 1.20-2.13), P = 0.001]. Limitations include an inability to distinguish biopsy from ILN dissection and those inherent in observational study design.
Conclusion: Utilization of SSILN for penile SCC is low and has not changed significantly since the publication of guidelines in the United States. In particular, nonacademic institutions were less likely to adhere to recommendations for performance of SSILNs. We found the omission of SSILNs is associated with a significant increase in mortality.
Keywords: Inguinal lymph node dissection; Inguinal lymphadenectomy; Penile cancer; Sentinel node biopsy; Survival.
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