Long-term survival after low-dose-rate brachytherapy for prostate cancer: the Royal Surrey experience.

OBJECTIVES: To assess the long-term treatment efficacy of low-dose-rate (LDR) brachytherapy for the treatment of localized prostate cancer. PATIENTS AND METHODS: Cause-of-death annotation in our prospective database was supplemented with death certificate information obtained via an internal audit of patients treated from 1999 to 2017 with LDR prostate brachytherapy as monotherapy or as combination with androgen deprivation therapy and/or external beam radiotherapy. Overall and disease-specific survival were the primary outcomes, estimated with Kaplan-Meier and competing risks multi-state models. Clinical variables influencing mortality were assessed with Cox proportional hazards regression in a sub-analysis of men to assess the predictive value of prostate-specific antigen (PSA) level at 48 months post implant. RESULTS: The audit process began in October 2017 and culminated in June 2020 with a curated series of 2936 patients. All-cause and prostate cancer-specific death prevalence were 11% and 2.9%, respectively. The median (range) follow-up time was 10 (3-21) years and the median (range) time to death from any cause was 9 (3-21) years. At 15 years post implant the overall and prostate cancer-specific survival probability were 81% and 95%, respectively. The 15-year cumulative incidence rates of death not due and due to prostate cancer were 14% and 5%, respectively. A greater risk of death due to prostate cancer was conferred by increasing age at therapy (hazard ratio [HR] 1.1, P < 0.001), advanced clinical stages relative to T1a-T2a (HR 1.9, P = 0.048 for T2b; HR 2.7, P = 0.023 for T2c-T3b) and a 48-month PSA level >1.0 ng/mL (HR 6.8, P < 0.001). CONCLUSION: This study constitutes the largest retrospective analyses of long-term mortality outcomes from prospectively collected prostate brachytherapy data and confirms the excellent treatment efficacy of LDR prostate brachytherapy for localized prostate cancer. T2 clinical stage subdivisions and 48-month PSA level >1.0 ng/mL appear to be strong indicators of prostate cancer-related survival.

Robot-assisted salvage seminal vesicle excision for isolated recurrence after low-dose-rate prostate brachytherapy.

OBJECTIVES: To report clinical and functional outcomes for patients who have undergone salvage robot-assisted seminal vesicle excision (RA-SVE) for the focal treatment of isolated seminal vesical (SV) recurrence after treatment for prostate cancer by low-dose-rate brachytherapy. PATIENTS AND METHODS: Patients with rising prostate-specific antigen (PSA) after low-dose-rate prostate brachytherapy (LDR-PB) underwent multi-parametric magnetic resonance imaging (mp-MRI) of the prostate and 11 C-Choline or 68 Ga-prostate-specific membrane antigen (68 Ga-PSMA) positron emission tomography/computed tomography (PET/CT) scan, followed by targeted transperineal biopsy of the prostate and SVs. Isolated SV recurrence were identified in 17 (0.38%) LDR-PB patients. These 17 patients were offered RA-SVE. RESULTS: The median total operative time was 90 min and blood loss 50 mL with no postoperative transfusions required. The median hospital stay was 1 day. No intra- or postoperative complications were documented. Continence status was unaffected, no patient required urinary pads. Postoperative pathology confirmed SV invasion in all specimens. Surgical margins were positive in seven (41%) patients. All patients had at least one positive imaging study, although three (18%) mp-MRI and five (29%) PET/CT assessments were negative. One (6%) pre-SVE biopsy was also negative but with positive imaging. Salvage SVE failure, defined as three consecutive PSA rises or the need for further treatment, occurred in six patients of whom three had a positive margin. Overall failure-free survival rates were 86%, 67%, and 53% at 1, 2, and 3 years after SVE, respectively. CONCLUSIONS: Salvage RA-SVE appears to be a safe focal treatment, with very low morbidity, for patients with localised SV recurrence after LDR-PB. It permits deferral of androgen deprivation therapy in selected patients. Bilateral SVE is mandatory. This surgical option should be considered in patients with isolated prostate cancer recurrence to the SV.

Hemi-ablative low-dose-rate prostate brachytherapy for unilateral localised prostate cancer.

OBJECTIVES: To report clinical outcomes of the Hemi-Ablative Prostate Brachytherapy (HAPpy) trial evaluating treatment-related toxicity and effectiveness of hemi-gland (HG) low-dose-rate (LDR) prostate brachytherapy as a focal approach to control unilateral localised prostate cancer. PATIENTS AND METHODS: Single institution phase IIS pilot study of patients treated with focal 4D Brachytherapy™ (BXTAccelyon, Burnham, Buckinghamshire, UK). The primary outcome was patient-reported toxicity 24 months after implant. The secondary outcome was assessment of disease control. Outcomes in HG patients were compared to whole-gland (WG) controls obtained from our prospective cohort registry by negative binomial and linear regression models. RESULTS: Pre-treatment demography was similar between the 30 HG patients and 362 WG controls. Post-implant dosimetry was similar for the prostate gland target volumes and significantly reduced for the urethra and bowel in HG patients relative to WG controls, but this did not translate into a difference in post-implant mean symptom scores between the two groups. Nevertheless, the change in score from baseline indicated that the impact on pre-treatment symptom status was less after HG implants. Only HG patients showed a return to baseline urinary scores as early as 12 months. Sexual potency was conserved in 73% and 67% of HG and WG patients, respectively (P = 0.84). Post-implant prostate-specific antigen (PSA) kinetics revealed that baseline PSA was reduced at 24 months by 78% and 88% in HG and WG patients, respectively (P < 0.05). Treatment relapse occurred in one (3%) HG patient 55 months after implant and in nine (3%) WG patients at 32-67 months after implant. CONCLUSION: This pilot study suggests that treatment-related toxicity and biochemical outcomes after HG implants are broadly similar to those observed with WG treatment despite the lower dose delivered by HG implants.

Long-term oncological outcomes and toxicity in 597 men aged ≤60 years at time of low-dose-rate brachytherapy for localised prostate cancer.

OBJECTIVES: To report oncological and functional outcomes of men treated with low-dose-rate (LDR) prostate brachytherapy aged ≤60 years at time of treatment. PATIENTS AND METHODS: Of 3262 patients treated with LDR brachytherapy at our centre up to June 2016, we retrospectively identified 597 patients aged ≤60 years at treatment with ≥3-years post-implantation follow-up and four prostate-specific antigen (PSA) measurements, of which one was at baseline. Overall survival (OS), prostate cancer-specific survival (PCSS) and relapse free survival (RFS) were analysed together with prospectively collected physician-reported adverse events and patient-reported symptom scores. RESULTS: The median (range) age was 57 (44-60) years, follow-up was 8.9 (1.5-17.2) years, and PSA follow-up 5.9 (0.8-15) years. Low-, intermediate- and high-risk disease represented 53%, 37% and 10% of the patients, respectively. At 10 years after implantation OS and PCSS were 98% and 99% for low-risk, 99% and 100% for intermediate-risk, and 93% and 95% for high-risk disease, respectively. At 10 years after implantation RFS, using the PSA level nadir plus 2 ng/mL definition, was 95%, 90% and 87% for low-, intermediate-, and high-risk disease, respectively. Urinary stricture was the most common genitourinary adverse event occurring in 19 patients (3.2%). At 5 years after implantation erectile function was preserved in 75% of the patients who were potent before treatment. CONCLUSION: LDR brachytherapy is an effective treatment with long-term control of prostate cancer in men aged ≤60 years at time of treatment. It was associated with low rates of treatment-related toxicity and can be considered a first-line treatment for prostate cancer in this patient group.

Low-dose-rate brachytherapy for the treatment of localised prostate cancer in men with a high risk of disease relapse.

OBJECTIVES: To report clinical outcomes of 125 I low-dose-rate prostate brachytherapy (LDR-PB) as monotherapy or combined with androgen-deprivation therapy (ADT) and/or external beam radiotherapy (EBRT) in high-risk localised prostate cancer. PATIENTS AND METHODS: Analysis of clinical outcomes from a prospective cohort of patients treated with LDR-PB alone or combined treatment in a single institution. Men with a high risk of disease relapse were identified by the National Institute for Health and Care Excellence (NICE) criteria or by the National Comprehensive Cancer Network (NCCN) criteria. Relapse-free survival (RFS), overall survival (OS), prostate cancer-specific survival (PCSS), and metastases-free survival (MFS), were analysed together with patient-reported symptom scores and physician-reported adverse events. RESULTS: The NICE and NCCN criteria identified 267 and 202 high-risk patients, respectively. NICE-defined patients had significantly lower pre-treatment PSA levels, Gleason scores <7, and a greater proportion of patients who received LDR-PB monotherapy. At 9 years after implantation RFS was 89% and 87% in the NICE and NCCN groups, respectively (log-rank P = 0.637), and OS 93% and 94%, respectively (log-rank P = 0.481). All of the survival estimates were similar between LDR-PB monotherapy and combined therapies. Cox proportional hazards regression confirmed RFS was similar between the treatment types. Treatment-related toxicity was also similar between the treatment methods. CONCLUSION: LDR-PB is effective at controlling localised prostate cancer in patients with a high risk of disease relapse. As the present study was not randomised, it is not possible to define those patients who need the addition of ADT and/or EBRT. However, the NICE criteria appear suitable to define treatment options where patients could benefit from LDR-PB as monotherapy or combined treatment. This choice should be discussed with the patient taking into account comorbidities and presence of multiple high-risk factors.

Net survival of men with localized prostate cancer after LDR brachytherapy.

OBJECTIVES: To compare survival of patients who received LDR prostate brachytherapy relative to that of peers in the general population of England, UK. PATIENTS AND METHODS: Net survival was estimated for 2472 cases treated between 2002 and 2016 using population-based analysis guidelines. Life tables adjusted for social deprivation in England from the Office for National Statistics were used to match patients by affluence based on their postcode. RESULTS: The median (range) age at time of brachytherapy was 66 (55-84) years, 84% resided in Southeast England, 51% under an index of deprivation quintile 5 (most affluent), 55% were clinical stage T1 and the remainder T2. Death from any cause occurred in 270 patients at a median (range) of 7 (1-17) years postimplant. Five and 10-year estimates (95% CI) of overall survival were 96% (95-97) and 90% (89-92), and net survival 103% (102-104) and 109% (107-110) respectively. The net survival remained above 100% in all age-at-treatment and clinical stage groups. CONCLUSION: Net survival above 100% indicates patients survive longer than the matched general population. The study shows for the first time the net survival of patients treated with a radical therapy for localized prostate cancer in England. The impact of treatment choice on the long-term net survival advantage requires further investigation.

Is hemi-gland focal LDR brachytherapy as effective as whole-gland treatment for unilateral prostate cancer?

PURPOSE: The Hemi-Ablative Prostate Brachytherapy (HAPpy) trial evaluated hemi-gland (HG) low-dose-rate prostate brachytherapy (LDR-PB) as a focal approach to control unilateral localized prostate cancer and reduce treatment-related toxicity at 2-years postimplant. Herewith we present further outcomes with a minimum of 5 years post-implant follow-up. METHODS AND MATERIALS: Outcomes of 30 HG implants and 362 whole-gland (WG) brachytherapy controls were monitored with IPSS, urinary Quality-of-Life (QoLU), GI component of EORTC-PR25 (QoLB), and IIEF-5 instruments, and PSA values. The median (range) follow-up for HG and WG cases was 72 (60-96) months and 84 (24-144) months respectively. RESULTS: The IPSS was significantly reduced in HG relative to WG patients and trends indicating improved bowel QoL and erectile function were observed. The mean of change in PSA from baseline to last follow-up was -5.6 and -6.5 in HG and WG respectively (p = 0.1). The mean time to nadir was 4.2 and 4.8 years in HG and WG respectively (p = 0.06). Over time PSA in HG patients mirrored the sustained decline observed in WG cases but levels were higher by an average 0.5 ng/ml over WG controls (p < 0.001). Treatment failure occurred in 2 (6.7%) HG patients and in 20 (5.5%) WG cases. Five-year relapse-free survival was 97% in both groups (p = 0.7). CONCLUSIONS: At 5 years postimplant HG LDR-PB was as effective as WG treatment for control of unilateral localized prostate cancer with moderate improvement in treatment-related symptoms. Importantly, PSA is a valuable marker to assess disease control in this form of focal therapy.

Hemi-gland focal low dose rate prostate brachytherapy: An analysis of dosimetric outcomes.

BACKGROUND AND PURPOSE: Advances in magnetic resonance imaging (MRI) and prostate sampling enable early identification of men with low to intermediate risk prostate cancer who are candidates for focal therapies that minimise side effects. We report dosimetry data from a pilot study evaluating the effectiveness of hemi-gland low dose rate (HG-LDR) brachytherapy as a focal therapy approach to control unilateral localised disease. MATERIAL AND METHODS: Twenty-two men underwent HG-LDR brachytherapy. Multi parametric MRI and transperineal template mapping biopsies were used to identify low volume unilateral disease. Whole gland therapy controls (n=120) were retrospectively obtained. All implants were performed with 4D Brachytherapy. RESULTS: Intraoperative and postimplant dosimetry complied with established brachytherapy parameters. Mean (standard deviation) postoperative D90 for the target hemi-gland was 153.8 (11.3) Gy compared to 47.5 (12.7) Gy for the contralateral hemi-gland (P<0.001). Mean postoperative V100% was 93.1 (3.9) and 24.6 (10.5) for the target and contralateral hemi-glands respectively (P<0.001). Urethra D30 was 150.4 (19.8) Gy and 174.2 (15.0) Gy for hemi-gland and whole gland implants respectively (P<0.001). Significantly reduced dose was also observed for rectum and neurovascular bundles. CONCLUSIONS: HG-LDR focal brachytherapy is feasible with significant reduction in dose to the contralateral hemi-gland and organs at risk.