Propensity score-matched analysis comparing dose-escalated intensity-modulated radiation therapy versus external beam radiation therapy plus high-dose-rate brachytherapy for localized 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.

Biochemical control in intermediate- and high-risk prostate cancer after EBRT with and without brachytherapy boost

PURPOSE

External beam radiotherapy (EBRT) with or without brachytherapy boost (BTB) has not been compared in prospective studies using guideline-recommended radiation dose and recommended androgen-deprivation therapy (ADT). In this multicenter retrospective analysis, we compared modern-day EBRT with BTB in terms of biochemical control (BC) for intermediate-risk (IR) and high-risk (HR) prostate cancer.

METHODS

Patients were treated for primary IR or HR prostate cancer during 1999-2019 at three high-volume centers. Inclusion criteria were prescribed ≥ 76 Gy EQD2 (α/β = 1.5 Gy) for IR and ≥ 78 Gy EQD2 (α/β = 1.5 Gy) for HR as EBRT alone or with BTB. All HR patients received ADT and pelvic irradiation, which were optional in IR cases. BC between therapies was compared in survival analyses.

RESULTS

Of 2769 initial patients, 1176 met inclusion criteria: 468 HR (260 EBRT, 208 BTB) and 708 IR (539 EBRT, 169 BTB). Median follow-up was 49 and 51 months for HR and IR, respectively. BTB patients with ≥ 113 Gy EQD2Gy experienced a stable, good BC outcome compared with BTB at lower doses. Patients treated with ≥ 113 Gy EQD2Gy also experienced significantly improved BC compared with EBRT (10-year BC failure rates after ≥ 113 Gy BTB and EBRT: respectively 20.4 and 41.8% for HR and 7.5 and 20.8% for IR).

CONCLUSIONS

In patients with IR and HR prostate cancer, BTB with ≥ 113 Gy EQD2Gy offered a BC advantage compared with dose-escalated EBRT and lower BTB doses.

Interactions between circRNAs and miR-141 in Cancer: From Pathogenesis to Diagnosis and Therapy

The function of non-coding RNAs (ncRNAs) in the pathogenesis and development of cancer is indisputable. Molecular mechanisms underlying carcinogenesis involve the aberrant expression of ncRNAs, including circular RNAs (circRNAs), and microRNAs (miRNAs). CircRNAs are a class of single-stranded, covalently closed RNAs responsible for maintaining cellular homeostasis through their diverse functions. As a part of the competing endogenous RNA (ceRNAs) network, they play a central role in the regulation of accessibility of miRNAs to their mRNA targets. The interplay between these molecular players is based on the primary role of circRNAs that act as miRNAs sponges, and the circRNA/miRNA imbalance plays a central role in different pathologies including cancer. Herein, we present the latest state of knowledge about interactions between circRNAs and miR-141, a well-known member of the miR-200 family, in malignant transformation, with emphasis on the biological role of circRNA/miR-141/mRNA networks as a future target for novel anti-cancer therapies.

Comparison of chronic gastrointestinal and genitourinary toxicities between brachytherapy and external beam radiotherapy for patients with prostate cancer: A systematic review and meta-analysis

BACKGROUND

125I BT is an effective radiotherapy for prostate cancer. However, comparison data of GI and GU toxicities between BT, BT + EBRT, and EBRT-alone patient groups is limited.

OBJECTIVE

To define the GI and GU toxicities in prostate cancer to prevent adverse events after treatment.

METHODS

We searched published studies in PubMed, Cochrane, and Embase databases up to December 31, 2022. The endpoints were the RRs of GI and GU toxicities. Pooled data were assessed using a random-effects model.

RESULTS

Fifteen eligible studies were included into this analysis. LDR-BT had significantly lower RRs than LDR-BT + EBRT for acute GI (2.13; 95% CI, 1.22-3.69; P= 0.007) and late GI toxicities (3.96; 95% CI, 1.23-12.70; P= 0.02). Moreover, EBRT had significantly higher RRs than LDR-BT for acute GU (2.32; 95% CI, 1.29-4.15; P= 0.005) and late GU toxicities (2.38; 95% CI, 1.27-4.44; P= 0.007). HDR-BT had significantly higher RRs for acute GU toxicities than LDR-BT alone (0.30; 95% CI, 0.23-0.40; P< 0.00001).

CONCLUSION

The results implied that BT with and without EBRT can result in both GI and GU toxicities in patients with prostate cancer, with LDR-BT leading to a poorer urinary function than EBRT.

Brachytherapy boost improves survival and decreases risk of developing distant metastases compared to external beam radiotherapy alone in intermediate and high risk group prostate cancer patients

BACKGROUND AND PURPOSE

Despite several prospective trials showing a clinical benefit of combining external beam radiotherapy (EBRT) with brachytherapy boost (BTB) for the treatment of intermediate- and high-risk prostate cancer (PCa) patients, none of these trials were designed to test for a survival difference. In this study, we aimed to collect a large multi-institutional database to determine whether BT boost was associated with a statistically significant improvement in survival and a reduction of distant metastases based on real-world data.

MATERIAL AND METHODS

We collected the data of patients treated for intermediate- or high-risk PCa with definitive EBRT or BTB, with or without androgen deprivation therapy (ADT), between January 2003 and December 2014 at two tertiary institutions. The statistical endpoints included overall survival (OS), freedom from distant metastases (FFDM), and metastases-free survival (MFS). The impact of treatment modality was assessed using Cox regression models and log-rank testing after one-to-one propensity score matching.

RESULTS

A total of 1641 patients treated with EBRT (n=1148) or high-dose-rate BTB (n=493) were analyzed. The median survival and clinical follow-up were 117.8 (IQR 78-143.3) and 60.7 months, respectively. The radiotherapy modality (BTB) remained an independent prognostic factor for OS (HR 0.75; 95% CI 0.63-0.88; p<0.001), FFDM (HR 0.54; 95% CI 0.4-0.73; p<0.001), and MFS (HR 0.72; 95% CI 0.61-0.85; p<0.001). After propensity score matching, the remaining 986 patients were well-balanced in terms of age, maximum PSA, ISUP grade group, and TNM T stage. OS (p=0.001), FFDM (p<0.001) and MFS (p<0.001) were significantly higher in the BTB group.

CONCLUSIONS

There is a strong positive association between BTB and OS, FFDM, and MFS in PCa patients treated with definitive RT for intermediate- or high-risk PCa.