Vascular Targeted Photodynamic Therapy with Padeliporfin for Low Risk Prostate Cancer Treatment: Midterm Oncologic Outcomes

Abstract

Purpose: We assessed the midterm oncologic outcomes of vascular targeted photodynamic therapy with padeliporfin for low risk prostate cancer treatment.

Materials and methods: We prospectively assessed all patients treated with vascular targeted photodynamic therapy for low risk prostate cancer at our center. Patients were followed every 6 months. All patients underwent prostate biopsies 6 months after treatment or when there was biological or clinical progression. The primary end point was progression-free survival. Secondary end points were absent clinically significant cancer in the treated lobes, radical therapy and the prostate specific antigen rate. Variables were compared with the chi-square, Mann-Whitney or Wilcoxon test. Progression-free survival is reported with Kaplan-Meier curves.

Results: A total of 82 men were treated with vascular targeted photodynamic therapy. Median followup was 68 months (range 6 to 89). Median progression-free survival was 86 months (95% CI 82-90). Median prostate specific antigen decreased significantly by 41% 6 months after treatment and it remained stable during followup (p <0.001). A total of 115 lobes were treated and absent clinically significant cancer was achieved in 94 (82%). Of the 82 patients 20 (24%) underwent radical therapy, including radical prostatectomy in 18 and brachytherapy in 2, at a median of 22 months (range 6 to 86). Study limitations include a single arm design, small population size and midterm followup.

Conclusions: Padeliporfin vascular targeted photodynamic therapy for low risk prostate cancer achieved an 82% rate of absent clinically significant cancer in treated lobes and 76% of patients avoided radical therapy at a median followup of 68 months. However, longer followup is required to determine long-term outcomes.

Keywords: WST11 compound; photochemotherapy; prostatic neoplasms; therapeutic occlusion; treatment outcome.