Factors associated with regional recurrence after lymph node dissection for penile squamous cell carcinoma.

OBJECTIVE: To identify factors associated with regional recurrence after lymph node dissection (LND) for squamous cell carcinoma (SCC) to determine which patients might benefit from adjuvant therapy.

PATIENTS AND METHODS: Men who underwent LND for penile SCC from 1977 to 2014 were identified from an institutional database. Kaplan-Meier curves estimated recurrence-free survival (RFS) calculated from the date of LND. Cox regression models evaluated the association between RFS and patient and tumour characteristics.

RESULTS: In all, 182 men who underwent LND for penile SCC were identified. The median patient age was 62 years and the median follow-up was 4.2 years. After LND 34 men had regional recurrence, of which 24 developed isolated regional recurrences without distant metastasis. The median RFS was 5.7 months, and the 3-year RFS rate was 70%. On univariate analysis, lymphovascular invasion, clinical and pathological nodal stage, pathological inguinal laterality, pelvic nodal involvement, lymph node density ≥5.2%, ≥3 pathologically involved lymph nodes, and extranodal extension (ENE) were associated with worse RFS (all P < 0.05). On multivariate analysis, clinical N3 disease [adjusted hazard ratio (AHR)] 3.53, 95% confidence interval (CI) 1.68-7.45; P = 0.001), ≥3 pathologically involved lymph nodes (AHR 3.78, 95% CI 2.12-6.65; P < 0.001), and ENE (AHR 3.32, 95% CI 1.93-5.76; P < 0.001) were associated with worse RFS. The 3-year RFS for patients with cN0, cN1, cN2, and cN3 disease was 91.7%, 64.5%, 54.7%, and 38.3%, respectively. For men with ≥3 involved nodes, the 3-year RFS was 17% vs 82.4% in men with <3 involved nodes. The 3-year RFS was 29.7% in men with ENE and 85.7% in men without ENE.

CONCLUSION: The presence of clinical N3 disease, ≥3 pathologically involved lymph nodes, and ENE was associated with worse RFS. As regional recurrence portends a dismal prognosis with few salvage options, adjuvant therapies should be developed for men with the aforementioned adverse factors.