Background: The aim of this study was 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).
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.