Direct comparison of low-dose-rate brachytherapy versus radical prostatectomy using the surgical definition of biochemical recurrence for patients with intermediate-risk prostate cancer

A Systematic Review of the Efficacy and Toxicity of Brachytherapy Boost Combined with External Beam Radiotherapy for Nonmetastatic Prostate Cancer

CONTEXT

The optimum use of brachytherapy (BT) combined with external beam radiotherapy (EBRT) for localised/locally advanced prostate cancer (PCa) remains uncertain.

OBJECTIVE

To perform a systematic review to determine the benefits and harms of EBRT-BT.

EVIDENCE ACQUISITION

Ovid MEDLINE, Embase, and EBM Reviews-Cochrane Central Register of Controlled Trials databases were systematically searched for studies published between January 1, 2000 and June 7, 2022, according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Eligible studies compared low- or high-dose-rate EBRT-BT against EBRT ± androgen deprivation therapy (ADT) and/or radical prostatectomy (RP) ± postoperative radiotherapy (RP ± EBRT). The main outcomes were biochemical progression-free survival (bPFS), severe late genitourinary (GU)/gastrointestinal toxicity, metastasis-free survival (MFS), cancer-specific survival (CSS), and overall survival (OS), at/beyond 5 yr. Risk of bias was assessed and confounding assessment was performed. A meta-analysis was performed for randomised controlled trials (RCTs).

EVIDENCE SYNTHESIS

Seventy-three studies were included (two RCTs, seven prospective studies, and 64 retrospective studies). Most studies included participants with intermediate-or high-risk PCa. Most studies, including both RCTs, used ADT with EBRT-BT. Generally, EBRT-BT was associated with improved bPFS compared with EBRT, but similar MFS, CSS, and OS. A meta-analysis of the two RCTs showed superior bPFS with EBRT-BT (estimated fixed-effect hazard ratio [HR] 0.54 [95% confidence interval {CI} 0.40-0.72], p < 0.001), with absolute improvements in bPFS at 5-6 yr of 4.9-16%. However, no difference was seen for MFS (HR 0.84 [95% CI 0.53-1.28], p = 0.4) or OS (HR 0.87 [95% CI 0.63-1.19], p = 0.4). Fewer studies examined RP ± EBRT. There is an increased risk of severe late GU toxicity, especially with low-dose-rate EBRT-BT, with some evidence of increased prevalence of severe GU toxicity at 5-6 yr of 6.4-7% across the two RCTs.

CONCLUSIONS

EBRT-BT can be considered for unfavourable intermediate/high-risk localised/locally advanced PCa in patients with good urinary function, although the strength of this recommendation based on the European Association of Urology guideline methodology is weak given that it is based on improvements in biochemical control.

PATIENT SUMMARY

We found good evidence that radiotherapy combined with brachytherapy keeps prostate cancer controlled for longer, but it could lead to worse urinary side effects than radiotherapy without brachytherapy, and its impact on cancer spread and patient survival is less clear.

Assessing the Efficacy and Long-Term Outcomes of Surgical Intervention Versus Radiotherapy: A Comprehensive Systematic Review and Meta-Analysis of Prostate Cancer Treatment Modalities

There is controversy regarding the most effective primary treatment of choice for prostate cancer (PCa) in terms of patient outcomes, such as surgery or radiotherapy (RT). This study evaluated the comparative efficacy and long-term outcomes of radical prostatectomy (RP) and RT for PCa treatment. A thorough literature review of relevant databases was conducted, focusing on academic and clinical studies published from 2019 onwards. The inclusion criteria included randomized controlled trials (RCTs) and other observational studies comparing survival outcomes in patients treated with surgery and RT. We followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines to provide an overview of the data. We selected 19 studies based on the inclusion criteria. Of the total 19 studies, 12 advocated RP as the preferred treatment to improve survival outcomes in patients with PCa. The results of our synthesis showed that prostate cancer-specific mortality (PCSM) was lower in patients treated with RT. The total effect size for the analysis was calculated as Z=1.19 (p-value=0.23). The heterogeneity in the studies was as follows: Tau2=0.09, Chi2=20.25, df=4, I2=80%. Moreover, overall survival (OS) was shown to be higher in patients who underwent prostatectomy. The combined effect for the analysis was found to be: HR=0.97 (0.93, 1.01). The total effect was calculated as Z=1.33 (p-value= 0.18). The heterogeneity was found to be Tau2=0.00, Chi2=1.33, df=2, and I2=0%. However, overall mortality (OM) was shown to be independent of the treatment modality. RT is the preferred strategy for PCa treatment, as it balances efficacy and long-term outcomes. Clinical decision-making should consider individual patient characteristics and future research should delve into specific subpopulations and long-term outcomes to further refine the treatment guidelines.

The oncologic and safety outcomes of low-dose-rate brachytherapy for the treatment of prostate cancer

Around 40 years have passed since a modern low-dose-rate (LDR) brachytherapy for prostate cancer was introduced. LDR brachytherapy has become one of the definitive treatment options besides radical prostatectomy (RP) and external beam radiation therapy (EBRT). LDR brachytherapy has several advantages over EBRT such as a higher prescribed dose to the prostate gland while avoiding unnecessary irradiation of organs at risk, a precipitous dose gradient, a brief treatment time, and a short hospital stay. Previous reports revealed that the long-term oncologic outcomes of LDR brachytherapy are superior to those of EBRT. The oncologic outcomes of low- to intermediate-risk patients are equivalent to those of RP using the recurrence definition of surgery of prostate specific antigen (PSA) >0.2 ng/mL, while the oncologic outcomes of LDR brachytherapy as tri-modality (combined EBRT and androgen deprivation therapy) for high-risk patients is superior to that of RP using the recurrence definition of surgery. In respect of toxicity, urinary disorders such as urgency and frequency are often observed after the acute phase of treatment, but these events usually resolve, while the quality of life of urinary continence is well preserved for a long time. Erectile function decreases yearly, but is relatively preserved compared to RP. In conclusion, the most noteworthy strength of LDR brachytherapy for low- to intermediate-risk patients is the "brief treatment time" that provides long recurrence-free survival, while that for high-risk patients who received LDR brachytherapy (tri-modality) is "excellent disease control."

Outcome comparison of radical prostatectomy versus seed brachytherapy for clinically localized prostate cancer using two biochemical recurrence definitions

OBJECTIVE

We compared the outcome of radical prostatectomy (RP) with seed brachytherapy (BT) in clinically localized prostate cancer (LPCa) using two different biochemical recurrence (BCR) definitions.

METHODS

Clinical data of 1117 patients with non-metastatic prostate cancer (PCa) treated with either RP or BT as the basis of the multimodal therapy from a single tertiary hospital between 2007 and 2021 were retrospectively analyzed. 843 LPCa patients (RP = 737, BT = 106) with at least one prostate-specific antigen (PSA) test after treatment were finally included. The BCR survival was evaluated by direct comparison and one-to-one propensity score matching (PSM) analysis using surgical definition (PSA ≥ 0.2ng/ml) for RP and surgical/Phoenix definition (PSA nadir + 2ng/ml ) for BT. The propensity score (PS) was calculated by multivariable logistic regression based on the clinicopathological parameters.

RESULTS

Median follow-up was 43 months for RP patients and 45 months for BT patients. Kaplan-Meier analysis did not show any statistically significant differences in terms of BCR-free survival (BFS) between the two groups when using Phoenix definition for BT (P > 0.05). Similar results were obtained in all D'Amico risk groups when stratified analyses were conducted. However, RP achieved improved BFS compared to BT in the whole cohort and all risk groups with the surgical definition for BT(P < 0.05). After adjusting PS, 192 patients were divided into RP and BT groups (96 each). RP presented a better BFS than BT when using the surgical definition (P < 0.001), but no significant difference was found when using the Phoenix definition (P = 0.609).

CONCLUSION

Inconsistent BCR-free survival outcomes were acquired using two different BCR definitions for BT patients. RP provided comparable BFS with BT using the Phoenix definition but better BFS using the surgical definition, regardless of whether the PSM was performed. Our findings indicated that an exact BCR definition was critical for prognostic assessment. The corresponding results will assist physicians in pretreatment consultation and treatment selection.

Seed-displacements in the immediate post-implant phase in permanent prostate brachytherapy

PURPOSE

To investigate differences in seed-displacements between the immediate post-implant phase (day 0-1) and the time to post-plan computed tomography (CT) (day 1-30) in seed prostate brachytherapy.

MATERIALS AND METHODS

Seed positions were identified on the intra-operatively created ultrasound-based treatment plan (day 0) and CT scans of day 1 and 30 for 33 patients. The day 1 (30) seed arrangement was registered onto the day 0 (1) arrangement using a seed-only approach. Based on a 1:1 assignment of seeds via the Kuhn-Munkres algorithm, seed-displacements were analyzed. Displacements were evaluated depending on strand-length and anatomical implant location. Resulting dosimetric effects were calculated.

RESULTS

Seed-displacements in the immediate post-implant phase (median displacements: 3.8 ± 3.6 mm) were stronger than in the time to post-plan CT (2.1 ± 2.6 mm) and enhanced along the superior-inferior direction. From day 0 to 1, strands containing one (7.3 ± 5.4 mm) or two (8.1 ± 5.8 mm) seeds showed larger displacements than strands of higher lengths (up to 4.2 ± 7.0 mm), whereas no length-dependency was found to day 30. Seeds implanted in base and apex tended to move towards the prostate midzone during both time periods. D₉₀ (dose that 90% of prostate receives) was with variations of 2 ± 15 Gy more stable from day 1 to 30 than in the immediate post-implant phase (-18 ± 11 Gy).

CONCLUSION

Seed-displacements in the immediate post-implant phase was enhanced compared to day 1-30. This may result from uncertainties in the gold-standard ultrasound-based treatment planning and implantation. Adaptive implantation workflows appear useful for ensuring high implant stability from the beginning.

Direct Comparison of Two Different Definitions with Biochemical Recurrence after Low-Dose-Rate Brachytherapy for Prostate Cancer

We aimed to determine whether biochemical recurrence-free survival (BRFS) of patients with prostate cancer (PCa) who received low-dose-rate brachytherapy (LDR-BT) differed according to the definition of biochemical recurrence (BCR) after radical prostatectomy (RP) and the definition given by the Japanese Prostate Cancer Outcome Study of Permanent Iodine-125 Seed Implantation (J-POPS). We reviewed the clinical records of 476 consecutive patients with PCa who received LDR-BT at the Gifu University Hospital. The primary endpoint of this study was the difference in BRFS between the two aforementioned definitions. When the follow-up period ended, 74 (15.5%) and 20 (4.2%) patients had BCR according to the RP and J-POPS definitions, respectively. The 5-year BRFS rates were 85.0% and 96.9% for the RP and J-POPS definitions, respectively (p < 0.005). According to the RP definition, the 5-year BRFS rates were 80.6% in the group aged <63 years and 86.6% in those aged ≥63 years (p = 0.050). According to the J-POPS definition, the 5-year BRFS rates were 94.1% and 97.8% in the groups aged <63 years and ≥63 years, respectively (p = 0.005). The definition of recurrence in LDR-BT may need to be reconsidered.