Variations in patterns of concurrent androgen deprivation therapy use based on dose escalation with external beam radiotherapy vs. brachytherapy boost for prostate cancer

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.

Assessing the toxicity after moderately hypofractionated prostate and whole pelvis radiotherapy compared to conventional fractionation

OBJECTIVE

To evaluate acute and late gastrointestinal (GI) and genitourinary (GU) toxicities after moderately hypofractionated (HF) or conventionally fractionated (CF) primary whole-pelvis radiotherapy (WPRT).

METHODS

Primary prostate-cancer patients treated between 2009 and 2021 with either 60 Gy at 3 Gy/fraction to the prostate and 46 Gy at 2.3 Gy/fraction to the whole pelvis (HF), or 78 Gy at 2 Gy/fraction to the prostate and 50/50.4 Gy at 1.8-2 Gy/fraction to the whole pelvis (CF). Acute and late GI and GU toxicities were retrospectively assessed.

RESULTS

106 patients received HF and 157 received CF, with a median follow-up of 12 and 57 months. Acute GI toxicity rates in the HF and CF groups were, respectively, grade 2: 46.7% vs. 37.6%, and grade 3: 0% vs. 1.3%, with no significant difference (p = 0.71). Acute GU toxicity rates were, respectively, grade 2: 20.0% vs. 31.8%, and grade 3: 2.9% vs. 0%, (p = 0.04). We compared prevalence of late GI and GU toxicities between groups after 3, 12, and 24 months and did not find any significant differences (respectively, p = 0.59, 0.22, and 0.71 for GI toxicity; p = 0.39, 0.58, and 0.90 for GU toxicity).

CONCLUSION

Moderate HF WPRT was well tolerated during the first 2 years. Randomized trials are needed to confirm these findings.

Enhancing Androgen Deprivation Therapy (ADT) integration in prostate cancer: Insights for Stereotactic Body Radiotherapy (SBRT) and brachytherapy modalities

The utilization of Androgen Deprivation Therapy (ADT) in conjunction with Stereotactic Body Radiotherapy (SBRT) and Brachytherapy (BT) boost in prostate cancer treatment is a subject of ongoing debate and evolving clinical practice. While contemporary trends lean towards underutilizing ADT with these modalities, existing evidence suggests that its omission may lead to potentially inferior oncologic outcomes. Recommendations for ADT use should be patient-centric, considering individual risk profiles and comorbidities, with a focus on achieving optimal oncologic outcomes while minimizing potential side effects. Ongoing clinical trials, such as PACE-C, SPA, SHIP 0804, and SHIP 36B, are anticipated to provide valuable insights into the optimal use and duration of ADT in both SBRT and BT settings. Until new evidence emerges, it is recommended to initiate ADT for unfavorable intermediate-risk and high-risk prostate cancer patients undergoing radiotherapy, with a minimum duration of 6 months for unfavorable intermediate-risk patients and at least 12 months for those with high-risk characteristics. The decision to incorporate ADT into these radiation therapy modalities should be individualized, acknowledging the unique needs of each patient and emphasizing a tailored approach to achieve the best possible oncologic outcomes.

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.

Suboptimal use of hormonal therapy among German men with localized high-risk prostate Cancer during 2005 to 2015: analysis of registry data

Background

This study assesses the use of hormonal therapy to treat high-risk localized prostate cancer (HRLPCa) cases diagnosed between 2005 and 2015.

Methods

All N_0-XM₀ with ≥T_3a, or PCa cases with poorly differentiated feature (equivalent to Gleason score ≥ 8), diagnosed between 2005 and 2015 were extracted from German population-based cancer registries. Cases treated by surgery or chemotherapy were excluded. Description of hormonal therapy use by HRLPCa cases’ profile was presented. Relative risk (RR) was computed with a log-link function to identify factors associated with hormonal therapy use among radiotherapy-treated HRLPCa cases.

Results

A total of 5361 HRLPCa cases were analyzed. Only 27.6% (95% confidence interval [CI]: 26.4–28.8%) of the HRLPCa cases received hormonal therapy in combination with radiotherapy. The use of combined hormonal therapy and radiotherapy varied from 19.8% in Saxony to 47.8% in Schleswig-Holstein.

Application of hormonal therapy was higher for the locally advanced cases compared to the poorly differentiated cases (relative risk [RR] = 1.28; 95%CI: 1.19, 1.37). Older patients showed a slightly increased use of hormonal therapy (RR for a 10-year age increase = 1.09; 95%CI: 1.02, 1.16). Compared to PCa cases from the most affluent residential areas, cases from the least affluent (RR = 0.71; 95%CI: 0.55, 0.92) and medium (RR = 0.75; 95%CI: 0.58, 0.96) areas had decreased use of hormonal therapy. The introduction of the German S3-guideline did not make a marked difference in the uptake of both hormonal therapy and radiotherapy (RR = 1.02; 95%CI: 0.95, 1.09).

Conclusion

This study found a low use of hormonal therapy among HRLPCa patients treated without surgery. The introduction of the German S3-guideline for prostate cancer treatment does not seem to have impacted hormonal therapy use.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09677-z.

Addition of Androgen-Deprivation Therapy or Brachytherapy Boost to External Beam Radiotherapy for Localized Prostate Cancer: A Network Meta-Analysis of Randomized Trials

PURPOSE

In men with localized prostate cancer, the addition of androgen-deprivation therapy (ADT) or a brachytherapy boost (BT) to external beam radiotherapy (EBRT) have been shown to improve various oncologic end points. Practice patterns indicate that those who receive BT are significantly less likely to receive ADT, and thus we sought to perform a network meta-analysis to compare the predicted outcomes of a randomized trial of EBRT plus ADT versus EBRT plus BT.

MATERIALS AND METHODS

A systematic review identified published randomized trials comparing EBRT with or without ADT, or EBRT (with or without ADT) with or without BT, that reported on overall survival (OS). Standard fixed-effects meta-analyses were performed for each comparison, and a meta-regression was conducted to adjust for use and duration of ADT. Network meta-analyses were performed to compare EBRT plus ADT versus EBRT plus BT. Bayesian analyses were also performed, and a rank was assigned to each treatment after Markov Chain Monte Carlo analyses to create a surface under the cumulative ranking curve.

RESULTS

Six trials compared EBRT with or without ADT (n = 4,663), and 3 compared EBRT with or without BT (n = 718). The addition of ADT to EBRT improved OS (hazard ratio [HR], 0.71 [95% CI, 0.62 to 0.81]), whereas the addition of BT did not significantly improve OS (HR, 1.03 [95% CI, 0.78 to 1.36]). In a network meta-analysis, EBRT plus ADT had improved OS compared with EBRT plus BT (HR, 0.68 [95% CI, 0.52 to 0.89]). Bayesian modeling demonstrated an 88% probability that EBRT plus ADT resulted in superior OS compared with EBRT plus BT.

CONCLUSION

Our findings suggest that current practice patterns of omitting ADT with EBRT plus BT may result in inferior OS compared with EBRT plus ADT in men with intermediate- and high-risk prostate cancer. ADT for these men should remain a critical component of treatment regardless of radiotherapy delivery method until randomized evidence demonstrates otherwise.

Combined Modality Therapies for High-Risk Prostate Cancer: Narrative Review of Current Understanding and New Directions

Despite the many prospective randomized trials that have been available in the past decade regarding the optimization of radiation, hormonal, and surgical therapies for high-risk prostate cancer (PCa), many questions remain. There is currently a lack of level I evidence regarding the relative efficacy of radical prostatectomy (RP) followed by adjuvant radiation compared to radiation therapy (RT) combined with androgen deprivation therapy (ADT) for high-risk PCa. Current retrospective series have also described an improvement in biochemical outcomes and PCa-specific mortality through the use of augmented radiation strategies incorporating brachytherapy. The relative efficacy of modern augmented RT compared to RP is still incompletely understood. We present a narrative review regarding recent advances in understanding regarding comparisons of overall and PCa-specific mortality measures among patients with high-risk PCa treated with either an RP/adjuvant RT or an RT/ADT approach. We give special consideration to recent trends toward the assembly of multi-institutional series targeted at providing high-quality data to minimize the effects of residual confounding. We also provide a narrative review of recent studies examining brachytherapy boost and systemic therapies, as well as an overview of currently planned and ongoing studies that will further elucidate strategies for treatment optimization over the next decade.