Presentation Authors: Shiva Nair*, London, Canada, Max Peters, Jochem van der Voort van Zyp, Marieke van Son, Utrecht, Netherlands, Joseph Chin, London, Canada
Introduction: Recurrent prostate cancer after primary radiotherapy occurs despite dose escalation, especially in higher risk groups. Local recurrence/failure can be treated using salvage therapy, thereby deferring subsequent non-curative systemic treatments. Tumor control results of salvage high intensity focused ultrasound (HIFU) at median 5 years follow-up are reported.
Methods: From April 2006 until March 2017, patients with histologically conformed recurrent prostate cancer were treated using whole-gland salvage HIFU (Sonablate, whole gland). Bone scan and CT (abdomen and pelvis) were negative for clinical metastatic disease. Data before salvage HIFU was collected to predict oncological outcomes. This included pre-radiation Gleason score and PSA, Charlson comorbidity index, age, pre-salvage PSA, pre-salvage prostate volume, pre-salvage use of ADT and PSA nadir post salvage. Overall survival (OS), prostate cancer specific survival (PCSS), metastases free survival (MFS) were calculated using the Kaplan-Meier method. After multiple imputation to account for missing data, Cox-regression was used to assess predictive factors for OS. Local ethic board approval was obtained for data collection and analysis.
Results: 87 patients with complete data on salvage HIFU were analyzed. Median follow-up was 65 months (interquartile range, [IQR] 36-122). Median age before salvage was 71 years (IQR 66-74), median PSA pre-salvage 3.8 ng/ml (IQR 2.3-5.1), median PSA nadir post HIFU 0.44 (IQR 0.04-1.41), median prostate volume 23.2cc (IQR 19.6-29). Most patients had Charlson comorbidity score 4 (31%), 5 (33.3%) or 6 (18.4%). 14.9% had primary Gleason 6 before radiation and 78.2% Gleason 7 or greater. 21.8% used ADT pre-salvage HIFU (all discontinued post-HIFU). Five-year OS was 83% (CI 75-92), PCSS was 89% (CI 82-97) and MFS was 85% (CI 77-94). Pre-salvage PSA predicted overall mortality in univariate analysis (P < 0.0001), but not in multivariate analysis. 51 patients (58.6%) were ADT free at last follow up with a median time to ADT at 118 months (CI 84-210).
Conclusions: Salvage HIFU can achieve high OS, PCSS and MFS in the medium term in properly selected patients with radiorecurrent prostate cancer. Prostate cancer radio-recurrence does not and should not automatically lead to ADT use. Urologists should include this in the option discussion for localized radiorecurrent disease, especially in men who may not be suitable for salvage radical prostatectomy due to comorbidities.