Focal HDR brachytherapy boost to stereotactic radiotherapy (fBTsRT) for prostate cancer: a phase II randomized controlled trial

Partial or focal brachytherapy for prostate cancer: a systematic review and meta-analysis

OBJECTIVES

Recent advances in image-guided brachytherapy have allowed for treatment volume reduction in the treatment of prostate cancer, with the aim to optimize disease control and reduce toxicities. This systematic review reports on the efficacy and safety of focal brachytherapy for treatment of patients with localized prostate cancer.

METHODS

Medline, Embase, Web of Science, and Cochrane were searched from inception to July 2023. Studies were included if they reported on focal brachytherapy, and described either dosimetry or clinical outcomes in the monotherapy or salvage setting. Meta-analysis was conducted to estimate biochemical control (BC) at 12-60 months. The review protocol was registered on PROSPERO (CRD42022320921).

RESULTS

Twenty-six studies reporting on 1492 patients were included in this review. Fourteen studies reported on monotherapy, 10 on salvage, and two on boost. The majority of studies used MRI and/or biopsy or PET for target identification, and MRI fusion and transrectal ultrasound (TRUS) for image guidance technique. BC for monotherapy was 97% (95% CI: 86%-99%) at 24 months and 82% (95% CI: 65%-92%) at 60 months. BC for salvage was 67% (95% CI: 62%-72%) at 24 months and 35% (95% CI: 17%-58%) at 60 months. Low rates of toxicity were reported across studies.

CONCLUSIONS

Focal brachytherapy has promising efficacy and safety profiles. Future studies may compare focal brachytherapy to whole-gland treatments, to investigate relative efficacy and safety.

ADVANCES IN KNOWLEDGE

In well-selected patients, partial or focal brachytherapy represents an evidence-based option with acceptable BC rates and a favourable toxicity profile.

Using multiparametric Magnetic Resonance Imaging and Prostate Specific Membrane Antigen Positron Emission Tomography to detect and delineate the gross tumour volume of intraprostatic lesions - A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Radiation therapy is used frequently for patients with prostate cancer. Dose escalation to intraprostatic lesions (IPLs) has been shown to improve oncologic outcomes, without increasing toxicity. Both multiparametric MRI (mpMRI) and PSMA PET can be used to identify IPLs.

MATERIALS AND METHODS

A systematic review was conducted to determine the ability of mpMRI, PSMA PET and their combination to detect IPLs prior to radical prostatectomy (RP) as correlated with the histology. Trials included patients that had mpMRI, PSMA PET, or both, prior to RP. The quality of the histopathological-radiological co-registration was assessed as high or low for each study. Recorded outcomes include sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC). A meta-analysis was conducted using a bivariate model to determine the pooled sensitivity and specificity for each imaging modality. This systematic review was registered through PROSPERO (CRD42023389092).

RESULTS

Altogether, 42 studies were included in the systematic review. Of these, 20 could be included in the meta-analysis. The pooled sensitivity (95 % CI), specificity (95 % CI) and AUROC for mpMRI (n = 13 studies) were 64.7 % (50.2 % - 76.9 %), 86.4 % (79.7 % - 91.1 %), and 0.852; the pooled outcomes for PSMA PET (n = 12) were 75.7 % (64.0 % - 84.5 %), 87.1 % (80.2 % - 91.9 %), and 0.889; for their combination (n = 5), the pooled outcomes were 70.3 % (64.1 % - 75.9 %), 81.9 % (71.9 % - 88.8 %), and 0.796. When reviewing studies with a high-quality histopathological-radiological co-registration, IPL delineation recommendations varied by study and the imaging modality used.

CONCLUSION

All of mpMRI, PSMA PET or their combination were found to have very good diagnostic outcomes for detecting IPLs. Recommendations for delineating IPLs varied based on the imaging modalities used and between research groups. Consensus guidelines for IPL delineation would help with creating consistency for focal boost radiation treatments in future studies.