Recent studies have reported improved outcomes with adjuvant radiotherapy in penile cancer. However, the appropriate target volumes to be irradiated in this group of patients for optimal outcomes are still unclear. This study aims to report the patterns of failure and define target volumes to be irradiated in patients with pN3 penile cancer.
Patients with pT1-T4, pN3, cM0, and squamous cell carcinoma of the penis who received adjuvant radiotherapy (involved field or extended field), with or without concurrent chemotherapy were included in the study. Complete information on disease characteristics, radiotherapy target details, and patterns of failure were available for 75 patients. Disease-free (DFS) and overall survival (OS) were estimated using the Kaplan-Meier method, and log-rank test was used to compare the survival outcomes between the involved field and extended field radiotherapy groups. Multivariate analysis was performed using the Cox proportional hazards model to analyze factors correlating with survival outcomes.
At a median follow-up of 39 months, 38.6% (29/75) of patients had relapsed either locally, regionally, or at distant sites. Of the 24 patients who received extended field radiotherapy (EFRT), only 1 (4%) patient experienced relapse, while 28 (55%) patients experienced relapse after involved-field radiotherapy (IFRT), of which 28.5% were regional-only relapses and 64% relapses were associated with a regional component. The 2-year DFS and OS of the entire cohort were 62.2% and 70.8%, respectively. The 2-year DFS was 67.9% in patients who received IFRT and 94.1% in those who received EFRT (p=0.002), while the 2-year OS was 62.4% with IFRT and 91.1% with EFRT (p=0.014). Extended field radiotherapy was associated with an improved DFS (HR- 12.2, 95% CI 1.5-97.4, p=0.02) and OS (HR- 4.6, 95% CI 1-21.5, p=0.05) on multivariate analysis.
Extended field radiotherapy significantly improves clinical outcomes compared to involved-field radiation in patients with pN3 penile cancer.
Practical radiation oncology. 2022 Nov 29 [Epub ahead of print]
Pallavi Khurud, Ankita Gupta, Rahul Krishnatry, Gitanjali Panigrahi, Reena Devi Phurailatpam, Santosh Menon, Mahendra Pal, Ganesh Bakshi, Gagan Prakash, Vedang Murthy
Department of Radiation Oncology, Tata Memorial Centre (TMH/ACTREC), Mumbai, India;; Homi Bhabha National Institute, Mumbai, India., Biotechnology, Clinical trial coordinator, Tata Memorial Centre (TMH/ACTREC), Mumbai, India;; Homi Bhabha National Institute, Mumbai, India., Department of Pathology, Tata Memorial Centre (TMH/ACTREC), Mumbai, India;; Homi Bhabha National Institute, Mumbai, India., Department of Surgical Oncology, Tata Memorial Centre (TMH/ACTREC), Mumbai, India;; Homi Bhabha National Institute, Mumbai, India., Department of Radiation Oncology, Tata Memorial Centre (TMH/ACTREC), Mumbai, India;; Homi Bhabha National Institute, Mumbai, India. Electronic address: .