MRI targeted single fraction HDR Brachytherapy for localized Prostate Carcinoma: a feasibility study of focal radiation therapy (ProFocAL)

Focal brachytherapy as definitive treatment for localized prostate cancer: A systematic review and meta-analysis

PURPOSE

In this systematic review and meta-analysis, we describe the oncologic and toxicity outcomes of definitive focal brachytherapy for prostate cancer.

METHODS AND MATERIALS

A PROSPERO registered study (CRD42023410170) was conducted following the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines. PubMed, Embase, and The Cochrane Library were searched for studies between 2000 and 2022. Two authors independently performed the initial search. Biochemical recurrence-free survival (bRFS) was defined as the primary endpoint for the meta-analysis. Generalized linear mixed-effects models were conducted to calculate effect size and quantify heterogeneity. We also describe the side effects and local recurrence patterns of focal brachytherapy.

RESULTS

Ten studies were identified and included 315 patients treated using focal brachytherapy as a definitive treatment. Mean (SD) age was 67.65 (7.9) years and mean (SD) PSA was 7.15 (2.7) ng/mL. Most patients (n = 236, 75%) underwent LDR Brachytherapy and 25% received HDR brachytherapy. Among the participants, 147 (46.5%) had a Gleason score ≤6, and 169 (53.5%) had a Gleason score ≥7. Only 11 (3.5%) patients received ADT. Overall, bRFS rate at median follow-up 4 years (Range: 1-6.42 years) was 91% (95% confidence interval [CI], 82-95%). Acute Grade ≤ 2 GU and GI toxicities were reported in 22 (7%) and 11 (3.5%) patients, respectively. Late Grade ≤ 2 GU and GI toxicity were reported in 6 (2%) and 14 (4.4%) patients, respectively. One case of prostate hemorrhage due to improper foley removal was noted but otherwise no acute or late Grade 3 or higher GI or GU toxicity related to radiotherapy was reported.

CONCLUSION

Overall, definitive focal brachytherapy has a favorable toxicity profile. Oncologic outcomes are yet to mature. The evidence is limited by the small number of studies with low patients' number, across study heterogeneity, and possibility of publication bias.

Feasibility of MRI targeted single fraction HDR brachytherapy for localized prostate carcinoma: ProFocAL-study

Purpose

A potential method for focal therapy in locally advanced prostate cancer is focal brachytherapy (F-BT). The purpose of this research was to evaluate midterm F-BT oncologic, functional, and toxicological results in men who had therapy for prostate cancer.

Materials and methods

Between 2016 and 2020, F-BT was used to treat 37 patients with low- to intermediate-risk prostate cancer. The recommended dosage was 20 Gy. Failure was defined as the existence of any prostate cancer that has persisted in-field after treatment. The F-BT oncologic and functional outcomes served as the main and secondary objectives, respectively.

Results

A median 20-month follow-up (range 14–48 months). 37 patients received F-BT and enrolled in the study; no patient experienced a biochemical recurrence in the first 24 months, according to Phoenix criteria. In the control biopsies, only 6 patients showed in-field failure. The median initial IPSS was 6.5, at 6 months was 6.0, and at 24 months was 5.0. When the median ICIQ-SF score was 0 at the baseline, it remained 0 at 6-, 12-, and 24 months. Overall survival and biochemical disease-free survival after 3 years were all at 100% and 86.4%, respectively. There was no notable acute gastro-intestinal (GI) or genitourinary (GU) adverse effects. No intraoperative or perioperative complications occurred.

Conclusions

For selected patients with low- or intermediate-risk localized prostate cancer, F-BT is a safe and effective therapy.

Feasibility of magnetic resonance imaging-ultrasound guided high-dose-rate brachytherapy for localized prostate cancer: Preliminary results from a prospective study

OBJECTIVE

This study aimed to investigate preliminary outcomes of a prospective trial of magnetic resonance imaging-ultrasound fusion-guided ultrafocal high-dose-rate brachytherapy in localized prostate cancer.

METHODS

In our prospective study, data from patients who underwent this treatment between April 1, 2020 and March 31, 2021 were analyzed. In the procedure, the applicator needle was inserted through the perineum to target the lesion on the multiparametric magnetic resonance imaging, which was fused onto the transrectal ultrasound image. The prescription dose was set at a single fraction of 19 Gy. Data from patients who received whole-gland high-dose-rate brachytherapy were extracted and compared with data from patients who received ultrafocal high-dose-rate brachytherapy, to evaluate the frequency of acute adverse events.

RESULTS

Eight patients underwent ultrafocal high-dose-rate brachytherapy with a median observation period of 7.75 months (range 5.96-15.36 months). No acute genitourinary or gastrointestinal adverse events were observed in this cohort. The planned procedure was completed in all patients, and no unexpected adverse events were observed; however, prostate-specific antigen failure was detected in one patient. In the 25 patients who underwent whole-gland high-dose-rate brachytherapy, acute genitourinary and gastrointestinal adverse events were observed in 88% and 20% of the patients, respectively. Ultrafocal high-dose-rate brachytherapy was a significant factor in avoiding acute adverse genitourinary events in univariate and multivariate analyses (P < 0.001 and P = 0.032, respectively).

CONCLUSIONS

Magnetic resonance imaging-ultrasound fusion-guided ultrafocal high-dose-rate brachytherapy in localized prostate cancer is a safe and feasible treatment without acute genitourinary and gastrointestinal adverse events. Long-term observation and further investigation are warranted.

Future perspective of focal therapy for localized prostate cancer

Objective

To summarize the recent literature discussing focal therapy for localized prostate cancer.

Methods

A thorough literature review was performed using PubMed to identify recent studies involving focal therapy for the treatment of localized prostate cancer.

Results

In an effort to decrease the morbidity associated with prostate cancer treatment, many urologists are turning to focal therapy as an alternative treatment option. With this approach, the cancer bearing portion of the prostate is targeted while leaving the benign tissue untouched. Multiparametric magnetic resonance imaging remains the gold standard for visualization during focal therapy, but new imaging modalities such as prostate specific membrane antigen/positron emission tomography and contrast enhanced ultrasound are being investigated. Furthermore, several biomarkers, such as prostate cancer antigen 3 and prostate health index, are used in conjunction with imaging to improve risk stratification prior to focal therapy. Lastly, there are several novel technologies such as nanoparticles and transurethral devices that are under investigation for use in focal therapy.

Conclusion

Focal therapy is proving to be a promising option for the treatment of localized prostate cancer. However, further study is needed to determine the true efficacy of these exciting new technologies.

Detailing Sexual Outcomes After Focal Therapy for Localised Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Focal therapy has emerged as a promising option to treat well-selected men with localised prostate cancer while preserving healthy prostate tissue and key structures, such as the urethral sphincter and neurovascular bundles. However, how this tissue preservation may translate into improved outcomes, particularly into improved sexual outcomes, is still an active research field.

OBJECTIVE

We conducted a systematic review and meta-analysis of the literature to summarise the existing evidence, in order to provide patients with updated data on what to expect after treatment and help identify gaps in current knowledge that may warrant future research.

EVIDENCE ACQUISITION

A systematic literature search was conducted on Medline, EMBASE, Scopus, and Web of Science. The search strategy was defined using the "litsearchr" function in R based on a preliminary "naïve" search using the following terms on Medline: (("focal therapy" OR "focal treatment") AND ("prostate cancer") AND ("sexual function" OR "erectile function")). A total of 42 studies, comprising 3117 patients treated and 2352 with available sexual outcomes, were included in the qualitative data synthesis and 26 in a random-effect meta-analysis.

EVIDENCE SYNTHESIS

The five-item International Index of Erectile Function (IIEF-5) was the most frequently used questionnaire (30/42 studies), with completion rates ranging from 24% to 100% at 18-24 mo. A decrease was noted at 3 mo (IIEF-5 decrease estimate -3.70 [95% confidence interval -4.43, -2.96]), with improvements at 6 mo (-2.18 [-2.91, -1.46]) and 12 mo (-2.14 [-2.96, -1.32]). Studies in which patients had an altered baseline sexual function were more likely to report a significant and durable postoperative decrease in erectile function scores. The patient-reported outcome questionnaires used were not designed for a diverse population. Functional outcomes were not the primary endpoint and have not been reported consistently in most studies considered.

CONCLUSIONS

Focal therapy led to changes in erectile function in most cases under the significance threshold of the patient-reported outcome questionnaires used. However, patients should be counselled according to their baseline erectile function. More research is warranted to detail aspects other than erectile function, such as ejaculation or orgasm. The early postoperative period appears key to study sexual changes after focal therapy, while only a moderate decrease is expected at 12 mo.

PATIENT SUMMARY

We reviewed the published literature detailing the sexual consequences of focal therapy for localised prostate cancer using patient-reported outcome questionnaires. Patients were likely to describe a significant decrease in their erectile function at 3 mo, with improvements noted at 6 and 12 mo. The results obtained may not be reproducible in a more diverse population, and further research is warranted to better study aspects other than erectile function, such as ejaculation or orgasm.

An Updated Systematic Review on Focal Therapy in Localized Prostate Cancer: What Has Changed over the Past 5 Years?

CONTEXT

Focal therapy is a promising, minimally invasive strategy to selectively treat localized prostate cancer. A previous systematic review indicated that there is growing evidence for favorable functional outcomes, but that oncological effectiveness was yet to be defined.

OBJECTIVE

To assess the effectiveness of focal therapy in patients with localized prostate cancer in terms of functional and oncological outcomes.

EVIDENCE ACQUISITION

PubMed, Embase, and The Cochrane Library were searched for studies between October 2015 and December 31, 2020. In addition, the research stages were acquired according to the Idea, Development, Exploration, Assessment, Long-term study (IDEAL) recommendations. Ongoing studies were identified through clinical trial registries.

EVIDENCE SYNTHESIS

Seventy-two studies were identified exploring eight different sources of energy to deliver focal therapy in 5827 patients. Twenty-seven studies reported on high-intensity focused ultrasound (HIFU), nine studies on irreversible electroporation, 11 on cryoablation, eight on focal laser ablation and focal brachytherapy, seven on photodynamic therapy (PDT), two on radiofrequency ablation, and one on prostatic artery embolization. The majority of studies were prospective development stage 2a studies (n = 35). PDT and HIFU, both in stage 3, showed promising results. Overall, HIFU studies reported a median of 95% pad-free patients and a median of 85% patients with no clinically significant cancer (CSC) in the treated area. For PDT, no changes in continence were reported and a median of 90% of patients were without CSC. Both treatments were well tolerated.

CONCLUSIONS

Over the past 5 yr, focal therapy has been studied for eight different energy sources, mostly in single-arm stage 2 studies. Although a first randomized controlled trial in focal therapy has been performed, more high-quality evaluations are needed, preferably via multicenter randomized controlled trials with long-term follow-up and predefined assessment of oncological and functional outcomes and health-related quality-of-life measures.

PATIENT SUMMARY

Focal treatment (FT) of prostate cancer has potential, considering that it has less impact on continence and potency than radical treatment. Our systematic review indicates that despite the method being studied extensively over the past half decade, the majority of studies remain in an early research stage. The techniques high-intensity focused ultrasound and photodynamic therapy have shown most progression toward advanced research stages and show favorable results. However, more high-quality evidence is required before FT can become available as a standard treatment.

HDR brachytherapy boost using MR-only workflow for intermediate- and high-risk prostate cancer: 8-year results of a pilot study

PURPOSE

To report 8-year clinical outcome with high-dose-rate brachytherapy (HDRBT) boost using MRI-only workflow for intermediate (IR) and high-risk (HR) prostate cancer (PC) patients.

METHODS AND MATERIALS

Fifty-two patients were treated with 46-60 Gy of 3D conformal radiotherapy preceded and/or followed by a single dose of 8-10 Gy MRI-guided HDRBT. Interventions were performed in a 0.35 T MRI scanner. Trajectory planning, navigation, contouring, catheter reconstruction, and dose calculation were exclusively based on MRI images. Biochemical relapse-free- (BRFS), local relapse-free- (LRFS), distant metastasis-free- (DMFS), cancer-specific-(CCS) and overall survival (OS) were analyzed. Late morbidity was scored using the Common Terminology Criteria for Adverse Events (CTCAE 4.0) combined with RTOG (Radiation Therapy Oncology Group) scale for urinary toxicity and rectal urgency (RU) determined by Yeoh.

RESULTS

Median follow-up time was 107 (range: 19-143) months. The 8-year actuarial rates of BRFS, LRFS, DMFS, CSS and OS were 85.7%, 97%, 97.6%, and 77.6%, respectively. There were no Gr.3 GI side effects. The 8-year actuarial rate of Gr.2 proctitis was 4%. The 8-year cumulative incidence of Gr.3 GU side effects was 8%, including two urinary stenoses (5%) and one cystitis (3%). EPIC urinary and bowel scores did not change significantly over time.

CONCLUSIONS

MRI-only HDR-BT boost with moderate dose escalation provides excellent 8-year disease control with a favorable toxicity profile for IRPC and HRPC patients. Our results support the clinical importance of MRI across the BT workflow.

Modern development of high-dose-rate brachytherapy

Brachytherapy is an invasive therapy with placement of radiation source into or near the tumor. The difference between planning target volume and clinical target volume is minimal, and the dose out of the tumor reduces rapidly due to the inverse-square law. High-dose-rate brachytherapy enables three-dimensional image guidance, and currently, tumor dose as well as doses of the surrounding normal structures can be evaluated accurately. High-dose-rate brachytherapy is the utmost precision radiation therapy even surpassing carbon ion therapy. Biological disadvantages of high-dose rate have been overcome by the fractional irradiation. High-dose-rate brachytherapy is indispensable in the definitive radiation therapy of cervical cancer. Also in prostate cancer and breast cancer, high-dose-rate brachytherapy plays a significant role. Brachytherapy requires techniques and skills of radiation oncologists at the time of invasive placement of the radiation source into the tumor area. Education of young radiation oncologists is most urgent and important.