We determined predictors of pelvic lymph node metastases in patients with penile cancer.

We retrieved a total of 188 node positive inguinal groins from 142 patients treated for penile cancer. Logistic regression models were fitted to test for predictors of pelvic lymph node metastases. The minimum p value method was used to determine the most significant cutoff values of each predictor.

Pelvic lymph node metastases were observed in 45 cases (31.7%). The 5-year cancer specific survival rate was 71.0% vs 33.2% in patients with inguinal vs pelvic lymph node metastases. The most significant cutoff values were 3 inguinal lymph node metastases and a metastasis diameter of 30 mm. According to univariable logistic regression models the number of inguinal metastases (OR 1.92, p <0.001), the diameter of the metastases (OR 1.03, p = 0.001) and extranodal extension (OR 8.01, p <0.001) were significant predictors of pelvic lymph node metastases. These variables were also independent predictors of metastases in multivariable logistic regression models (p ≤ 0.012). Patients with 3 or more inguinal lymph node metastases and those with a metastasis diameter of 30 mm or greater were at 4.77 and 2.53-fold higher risk, respectively, of harboring pelvic lymph node metastases (p ≤ 0.006). The proportion of metastases increased significantly from 0% in cases with no risk factors to 57.1% when all 3 risk factors were observed (p <0.001).

The number and diameter of inguinal lymph node metastases as well as extranodal extension are significantly associated with pelvic lymph node metastases. These variables should be considered to determine the need for pelvic lymph node dissection. Patients with no risk factors may be spared this dissection.