Pattern of invasion is the most important prognostic factor in patients with penile cancer submitted to lymph node dissection and pathological absence of lymph node metastasis

Objectives To identify prognostic factors in a cohort of patients with penile carcinoma with pathological absence of lymph node metastasis (pN0), as penile carcinoma is a rare neoplasm in European countries, in which the presence of lymph node metastasis is the most important prognostic factor but few studies have examined patients with penile carcinoma with histologically negative nodes (pN0). Patients and Methods Of patients with penile carcinoma, 101 met the inclusion criteria; 47 (46.5%) underwent bilateral inguinal lymph node dissection (LND) and 54 (53.5%) underwent bilateral inguinopelvic LND. Variables that had a prognostic impact on survival rates in univariate analysis were selected for multivariate survival analysis. Results The cohorts cancer-specific survival (CSS) and overall survival (OS) rates were 88.1% and 52.5%, respectively. Histological grade and pattern of invasion were the only features to significantly impact survival rates in the univariate analysis. The CSS and OS rates in patients with 'pushing' vs 'infiltrating' patterns of invasion were 98.0% vs 78.4% (P = 0.003) and 70.0% vs 35.3% (P = 0.005), respectively. Pattern of invasion was the only independent predictor of survival. Patients with infiltrating invasion had a higher probability of death from cancer (hazard ratio [HR] 11.5, P = 0.019) and overall death (HR 2.3, P = 0.007) compared with those with a pushing invasion pattern. Conclusions The presence of an infiltrating pattern of invasion is the most important predictor of survival in patients with penile carcinoma. We encourage other centres to confirm our findings that the pattern of invasion is an important prognostic factor in patients with penile carcinoma and pN0 disease.