Risk factors for lymph node metastasis in clinically node-negative penile cancer patients

Objectives: To analyze the effects of pathological T stage, grade, extent of surgery for primary tumor, and age group on the risk of developing lymph node metastasis in clinically node-negative penile cancer patients. Methods: We performed a retrospective analysis of 200 clinically node-negative penile cancer patients who were kept under surveillance, after treatment of the primary tumor in our institution. The primary outcome parameter was cytologically or histologically proven lymph node metastasis. Logistic regression analysis was used to compute odds ratios in univariate and multivariate settings. Results: Lymph node metastasis occurred in 31 patients at a median time of three months. Histological grade 3 and grade 2 tumors had a statistically significant increased odds ratio for lymph node metastasis, (7.1[P < 0.001] and 2.7 [P = 0.04], respectively), compared with grade 1 tumors. Although increasing pT stage was associated with increasing odds ratios, the differences were not statistically significant. Nor did the extent of surgery of the primary tumor or the age group significantly influence the risk of developing lymph node metastasis. Conclusions: Histological grade is the most significant parameter influencing the risk of lymph node metastasis in clinically node-negative penile cancer patients on surveillance. Patients with grade 3 and grade 2 tumors may benefit from elective inguinal lymphadenectomy.