Factors predicting inguinal node metastasis in squamous cell cancer of penis.

PURPOSE: To identify factors predicting the risk of inguinal metastasis in squamous cell carcinoma of the penis. The therapeutic advantages of early lymphadenectomy in squamous cell carcinoma of the penis must be counterbalanced against its post-operative morbidity. Loss to follow up is a major problem in developing countries. Generating a nomogram based on clinical lymph node status and histopathological findings in the primary tumor could facilitate clinical decision making in the management of penile cancer.

METHODS: We prospectively studied 106 patients with penile squamous cell cancer treated from September 2001 to August 2007 at our institution. All patients were offered lymphadenectomy (LAD). A multivariate logistic regression model was used to develop a nomogram. We highlight the problems of loss to follow up in these patients.

RESULTS: Of 53 who opted for LAD, 22 had nodal metastasis. The presence of high grade (P = 0.004), lymphovascular invasion (LVI) (P = 0.01) and palpable inguinal lymph nodes (P = 0.05) were the strongest predictors of metastasis. Of 51 who refused LAD, 22 were lost to follow up. Out of these, 16 were at high risk and 9 of them came back with inoperable fungating nodes. A nomogram predicting the risk of lymph node metastasis showed a bias corrected good concordance index (0.74) and good calibration.

CONCLUSIONS: High grade and LVI in the tumor along with clinical stage of the inguinal nodes were the strongest predictors of metastasis. These features helped us to develop a nomogram to predict and to identify patients at risk of nodal metastasis.