Is there any benefit in adding postoperative adjuvant concurrent radiotherapy and chemotherapy for penile cancer with regional lymph node metastasis?

PURPOSE To evaluate whether there is any benefit in adding postoperative adjuvant concurrent radiotherapy and chemotherapy (RT-CHT) for penile cancer with regional lymph node metastasis (RLNM). MATERIALS AND METHODS A single institution, retrospective study was conducted for a total of 23 patients with RLNM from penile squamous cell carcinoma. All underwent a definitive surgical intervention for both primary tumor and RLNM. Of these, 11 patients received adjuvant concurrent RT and CHT within 3 months after surgery (RT-CHT Group), while 12 patients received no additional treatment (Surveillance Group). Overall survival was calculated with the Kaplan-Meier method. The difference in survival between the two groups was tested using the log-rank test. A potential prognostic factor for survival was evaluated using a univariate Cox-proportional hazards model. RESULTS Median follow-up for the entire group was 15.8 months (17.1 months for the RT-CHT group and 10.7 months for the Surveillance Group). Overall survival at 1 and 2 years were 54.5% and 27.2%, respectively, for the RT-CHT Group, compared to 57.1% and 28.4% for the Surveillance Group (log-rank=0.68). On a univariate analysis, the number of involved lymph nodes and the presence of pN3 disease were associated with poor prognosis (p>0.001 and p=0.049, respectively). The RT-CHT Group had more extensive RLNM with a higher median number of positive nodes (5 vs. 3) and more pN3 disease (72.7% vs. 16.7%) than the Surveillance Group. The rate of complications requiring hospitalization was higher in the RT-CHT Group (63.6% vs. 16.6%; p=0.02), as was the rate of systemic complications (34.7% vs. 0%; p <0.01). CONCLUSIONS Penile cancer with extensive RLNM carries a poor prognosis. Despite having more extensive RLNM, the RT-CHT group had a similar overall survival as the Surveillance Group. This suggests a potential benefit of postoperative adjuvant concurrent RT-CHT for patients with extensive RLNM, although it carries an increased risk of complications. Further study is warranted to assess the benefit-to-risk ratio of this combined adjuvant therapy.