Optimising the selection of candidates for neoadjuvant chemotherapy amongst patients with node-positive penile squamous cell carcinoma

Objectives: To identify predictors of poor overall survival (OS) amongst patients with penile squamous cell carcinoma (pSCC) with clinical inguinal lymphadenopathy (cN+), in order to define the best candidates for neoadjuvant chemotherapy (NAC).

Patients and methods: Using an international, multicentre database of 924 patients with pSCC, we identified 334 men who harboured cN+ with available clinical and follow-up data. Lymph node involvement was defined either by the presence of palpable inguinal node disease or by preoperative computed tomography (CT) assessment. Fluorine-18 fluorodeoxyglucose positron-emission tomography (¹⁸ F-FDG-PET)/CT scan was performed based on clinical judgment of the treating physician. Regression-tree analysis generated a risk stratification tool for prediction of 24-month overall mortality (OM). Kaplan-Meier explored the OS benefit related to the use of NAC according to the regression-tree-stratified subgroups.

Results: Overall, 120 (35.9%), 152 (45.5%), and 62 (18.6%) patients harboured cN1, cN2, and cN3 disease. ¹⁸ F-FDG-PET/CT was performed in 48 (14.4%) patients, and 16 (4.8%) had inguinal and pelvic nodal PET detection. The median OS was 107 months, with a 24-month OS of 66%. At regression-tree analysis (area under the curve = 70%), patients with cN3 and cN2 with PET/CT-detected inguinal and pelvic nodal activity had a higher risk of 24-month OM (>50%). NAC was associated with improved 24-month OS rates (54% vs 33%) only in this subgroup of patients (P = 0.002), which was also confirmed after multivariable adjustment (hazard ratio 0.28, 95% confidence interval 0.13-0.62; P = 0.002).

Conclusion: Patients with pSCC with cN3 or cN2 and inguinal and pelvic 18F-FDG-PET/CT scan detected disease had higher 24-month OM rates according to our regression-tree model. NAC was associated with improved OS only in these subgroups of patients. Our novel decision model may help to stratify cN+ patients, and identify those who most likely will benefit from NAC prior to radical surgical resection.