Salvage HDR brachytherapy for prostate cancer: a high-volume center experience on 100 consecutive patients

Salvage Magnetic Resonance Imaging-guided Transurethral Ultrasound Ablation for Localized Radiorecurrent Prostate Cancer

Background and objective

Toxicity from local salvage therapy for radiorecurrent prostate cancer (PCa) remains a concern. This phase 2 study evaluates the outcomes of salvage magnetic resonance imaging (MRI)-guided transurethral ultrasound ablation (sTULSA).

Methods

Men with biochemically relapsed, biopsy-proven PCa following definitive radiotherapy underwent whole- or partial-gland sTULSA (NCT03350529). Prostate-confined recurrence was confirmed by MRI and prostate-specific membrane antigen (PSMA) positron emission tomography (PET) computed tomography (CT). The primary endpoints were safety (Clavien-Dindo classification) and efficacy (prostate-specific antigen [PSA], PSMA PET-CT, and MRI-targeted biopsy at 12 mo). The secondary endpoints included functional and survival outcomes.

Key findings and limitations

Thirty-nine patients underwent sTULSA (64% whole gland), with a median age of 73 yr (interquartile range [IQR]: 69-77) and PSA of 3.3 ng/ml (IQR: 2-6.2). Three patients had undergone prior salvage therapy, 16 were receiving hormonal therapy at enrollment, and 12 had a history of transurethral interventions. Eighteen patients had incidental urethral strictures on baseline cystoscopy. Over a median follow-up of 40 mo (IQR: 24-55), 56% experienced adverse events. Severe genitourinary toxicity (Clavien-Dindo ≥3 or hospitalization) occurred in 28%, including three patients with puboprostatic fistulas and two patients requiring cystectomy. Leak-free continence was maintained in 53%. At 12 mo, 89% showed no cancer in the targeted area, with a median PSA reduction of 95% (p < 0.001). Five-year metastasis-free, failure-free, and biochemical recurrence-free survival probabilities (95% confidence interval) were 97% (0.93-1.00), 70% (0.54-0.91), and 54% (0.31-0.93), respectively. Limitations included single-arm design and moderate sample size.

Conclusions and clinical implications

It has been observed that sTULSA is effective for radiorecurrent PCa, although genitourinary toxicity remains a concern. Further studies should refine patient selection and treatment parameters to improve safety and tolerability.

Patient summary

In this study, we examined a new treatment called magnetic resonance imaging-guided transurethral ultrasound ablation for prostate cancer that has returned after radiation therapy. We found that the treatment provided effective and lasting cancer control for most patients. However, a notable number of patients experienced significant genitourinary toxicity, including severe adverse effects affecting urinary function. Careful patient selection is crucial to minimize these adverse effects and ensure the best results.

Salvage reirradiation for locally recurrent prostate cancer: A narrative review

In this narrative review, we will explore the different options for salvage re-irradiation for locally recurrent prostate cancer. Brachytherapy (BT) and stereotactic body radiation therapy (SBRT) appear to be successful options. We detailed doses, volumes, oncological outcomes, and toxicity events to identify the best salvage strategy. Salvage reirradiation can only be proposed in certain cases, depending on the patient and the clinical scenario. Specific imaging and tests are needed to safely deliver this treatment.

Salvage low-dose-rate brachytherapy for locally recurrent prostate cancer after definitive irradiation

Purpose

The optimal management of locally recurrent prostate cancer after definitive irradiation is still unclear but local salvage treatments are gaining interest. A retrospective, single-institution analysis of clinical outcomes and treatment-related toxicity after salvage I-125 low-dose-rate (LDR) brachytherapy (BT) for locally-recurrent prostate cancer was conducted in a Comprehensive Cancer Center.

Patients and methods

A total of 94 patients treated with salvage LDR-BT between 2006 and 2021 were included. The target volume was either the whole-gland +/- a boost on the GTV, the hemigland, or only the GTV. The prescribed dose ranged from 90 to 145 Gy. Toxicity was graded by Common Terminology Criteria for Adverse Events (CTCAE) v5.0.

Results

Median follow-up was 34 months. Initial radiotherapy was external beam radiotherapy in 73 patients (78 %) with a median dose of 76 Gy and I-125 BT in 21 patients (22 %) with a prescribed dose of 145 Gy. Median PSA at salvage was 3.75 ng/ml with a median interval between first and salvage irradiation of 9.4 years. Salvage brachytherapy was associated with androgen deprivation therapy for 32 % of the patients. Only 4 % of the patients were castrate-resistant. Failure free survival was 82 % at 2 years and 66 % at 3 years. The only factors associated with failure-free survival on multivariate analysis were hormonosensitivity at relapse and European Association of Urology (EAU) prognostic group. Late grade 3 urinary and rectal toxicities occurred in 12 % and 1 % of the patients respectively.No significant difference in toxicity or efficacy was observed between the three implant volume groups.

Conclusion

The efficacy and toxicity results are consistent with those in the LDR group of the MASTER meta-analysis. Salvage BT confirms to be an effective and safe option for locally recurrent prostate cancer. A focal approach could be interesting to reduce late severe toxicities, especially urinary.

Evaluation of the safety and efficacy of high-dose rate brachytherapy for radiorecurrent prostate cancer: a systematic review and meta-analysis

BACKGROUND

High-dose-rate brachytherapy (HDR-BT) plays an important role in the treatment of locally recurrent prostate cancer after definitive treatment. The objective of this study is to summarize the efficacy and toxicity of HDR-BT in these patients.

METHODS

We performed a systematic review of PubMed and EMBASE from inception to July 2023. The primary endpoint was relapse-free survival (RFS) in different subgroups, and the secondary endpoint was gastrointestinal (GI) and genitourinary (GU) toxicity. A semi-automated tool (WebPlotDigitizer) and a new Shiny application combined with R software (R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria; https://www.R-project.org/ ) helped to reconstruct survival curves.

RESULTS

Twenty-six studies met the inclusion criteria for quantitative analysis, including 1447 patients. A total of 761 patients from 13 studies were included in survival reconstruction, and the median RFS time was 61.2 months (57.6-72.0 months). The estimated 2‑, 3‑, and 5‑year rates were 75.9% (95% confidence interval [CI] 72.8 ~ 79.2%), 66.7% (95% CI 63.0 ~ 70.5%), and 52.3% (95% CI 47.5 ~ 57.4%), respectively. Whole-gland irradiation with multiple fractions (≥ 2 F) resulted in better RFS compared with focal gland irradiation with fewer fractions (1 F mostly; hazard ratio [HR]: 0.60, 95% CI 0.47-0.77, p < 0.0001). According to the different median time from primary treatment to salvage therapy (TRS) and median age at recurrence, short median TRS (56-67.2 months vs. 70-120 months; HR 0.52, 95% CI 0.68-0.40; p < 0.0001) and younger median age (60-70 years vs. 71-75 years; HR 0.58, 95% CI 0.46-0.74; p < 0.0001) were positive factors for RFS. The cumulative incidences estimated for grade ≥ 3 acute and late GU toxicities were 1% (95% CI 0 ~ 1%) and 5% (95% CI 4 ~ 7%), respectively. Three patients (3/992) experienced grade ≥ 3 late GI toxicity, and no cases of grade ≥ 3 acute GI toxicity were reported.

CONCLUSION

HDR-BT has a high safety profile and good RFS benefit for salvage treatment of radiorecurrent prostate cancer. In terms of RFS, whole-gland irradiation with multiple fractions seems to be better than focal gland irradiation with fewer fractions, while short TRS and younger age are good prognostic factors. In view of the low level of evidence in the included studies and the large heterogeneity of each study, these conclusions still need to be confirmed by randomized controlled trials.

Optimal Strategies for Managing Prostate-specific Antigen Recurrence After Primary Radiotherapy in Prostate Cancer: The Finnish Perspective

Biochemical recurrence after radiotherapy for prostate cancer is a clinical dilemma. Patients at low risk of disease progression can be safely monitored. In Finland, options for those with reasonable life expectancy include salvage high-dose-rate brachytherapy and transurethral ultrasound ablation under magnetic resonance imaging guidance.