Following institutional review board approval (HREC approval SVH 13/018 and 16/110), data were retrieved from a single centre (St. Vincent’s Prostate Cancer Centre, Sydney, Australia) prospective database of patients treated with primary focal IRE between February 2013 and January 2020.
Patients that underwent a sRARP at our institution after at least one prior IRE procedure were included in the analysis. Patients were only included in the study if they had at least 12-month follow-up from the sRARP. No patient underwent an open radical prostatectomy in this series. We included consecutive patients with histopathological confirmed residual or recurrent clinically significant PCa. Salvage treatment (sRARP, radiotherapy or re-do IRE ablation) was offered to patients whose post-IRE biopsy showed clinically significant PCa (Gleason grade group ≥ 2)(table 1). It was an institution policy to offer a maximum of two focal therapy sessions per patient. All patients are offered a consultation with a radiation oncologist independently.
Indications for sRARP in this setting included -
1. Multifocal intermediate risk prostate cancer following IRE
2. Patients’ decision not to undergo further focal ablation therapy
3. Two treatments of focal ablation with further significant recurrence
4. Significant upgrading in PCa not amenable to further focal ablation
5. Physicians lack of comfort with persisting with focal therapy.
Metastatic disease was excluded by prostate-specific membrane antigen (PSMA)/positron emission tomography (PET) scan. All patients had a life expectancy greater than 10 years. Patients who previously received androgen deprivation therapy or radiotherapy were excluded. All sRARP’s were performed by a single surgeon (PS). Decisions about neurovascular bundle preservation were made by the surgeon based on intraoperative findings, prior imaging and biopsy. A pelvic lymph node dissection was performed, where appropriate according to Briganti nomogram (>5 risk of LNMs). All pathological specimens were reviewed by a dedicated uro-pathologist (WDP).
In our institution, patients undergoing FA with IRE are monitored rigorously during follow up with serial PSA levels (every three months for the first year and then every six months thereafter). All patients undergo a T1/T2 MRI within a week of treatment to ensure adequate ablation of the intended area and then a multiparametric MRI (mpMRI) at six months post treatment to assess for recurrence/residual disease. Patients subsequently undergo a transperineal biopsy (template with targeted biopsies of ablated area) at 12 months (or earlier if suspicion on MRI) to assess for oncological control. Follow up schedule or salvage treatment is dictated thereafter by the 12-month post treatment biopsy.
IRE data was collected prospectively for each patient. The data that was collected included: age at IRE ablation, PSA level prior to treatment, pre-treatment biopsy Gleason score, mpMRI, area ablated, ablation treatment parameters including number of electrodes, volts and sets, post treatment PSA levels, mpMRI and biopsy results. It was also recorded if a patient had a second IRE ablation prior to prostatectomy.
For each patient data for sRARP was collected retrospectively. This data included: age at surgery, date of surgery, pre-treatment PSA level and biopsy Gleason score, histopathological data from sRARP, operative data, post-operative complications, follow-up PSA levels, need for adjuvant/salvage treatment and patient-reported continence and erectile function measures (collected by independent data managers).
Urinary continence was strictly defined as self-reported lack of need for continence pads (0 pads usage). Patients were considered potent when they had self-reported erections firm enough for penetrations with or without the use of a phosphodiesterase type 5 inhibitor.
Quantitative variables are shown in median and interquartile (IQR) scores. A Mann-Whitney U test was used to compare pre-operative parameters with the development of erectile dysfunction after sRARP. Statistical analysis was done with the R statistical environment, versions 3.1.0. Statistical significance was considered p < 0.05.