Long-term outcomes of ultra-hypofractionated 2 fractions single day HDR brachytherapy in localized prostate cancer

High-dose-rate (2 fractions of 13.5 Gy) and low-dose-rate brachytherapy as monotherapy in prostate cancer. Long term outcomes and predictive value of nadir prostate-specific antigen

PURPOSE

This study aims to evaluate the outcomes of patients treated for low-risk (LR) and favorable intermediate risk (FIR) prostate cancer with brachytherapy (BT) in monotherapy with LDR or HDR and its relationship with nadir PSA (nPSA).

MATERIALS AND METHODS

We retrospectively analyzed 139 patients (2005-2019) with exclusive LDR (46%. 145/160 Gy) /HDR (54%. 2 implants of 13.5 Gy each separated 10 days). 69% LR and 31% FIR. PSA nadir was grouped into two categories: ≤ 0.2 ng/mL and > 0.2 ng/mL.

RESULTS

Median patient age was 69 years (46-84). Seventy-six patients (55%) received androgen deprivation therapy, and 37% received neoadjuvant therapy. Median follow-up period was 90 months. Actuarial biochemical failure-free survival (BFFS), local control (LC), overall survival (OS), and cause-specific survival (CSS) rates for the total cohort were 78%, 87%, 68%, and 98% at 10 years, respectively. BFFS, LC, OS and CSS in nPSA ≤ 0,2 ng/ml was 90%, 96%, 67%, 100% at 10 years respectively, whereas, those with a nPSA > 0.2 ng/ml had a BFFS, LC, OS and CSS of was 37%, 51%, 72%, 90% at 10 years respectively Statistical significance between both groups was reached in BFFS (p=0,000), LC (p=0,000) and CSS (p=0,007)). In the univariate analysis, there was no difference between risk stratification, BT technique, ADT, or the development of bouncing.

CONCLUSIONS

Prostate brachytherapy as monotherapy (LDR and HDR) is an effective treatment option for patients with LR and FIR prostate cancer. nPSA ≤0,2 ng/ml is a representative value that provides prognostic information for favorable outcomes in this group of patients.

Mature effectiveness and toxicity outcomes associated with three treatment schedules of high-dose-rate brachytherapy monotherapy for favorable-risk prostate cancer

PURPOSE

To present long-term toxicity and effectiveness outcomes of three prostate high-dose-rate (HDR) brachytherapy schedules: 38 Gy in 4 fractions, 24 Gy in 2 fractions, and 27 Gy in 2 fractions for men with low- or intermediate-risk prostate cancer.

METHODS AND MATERIALS

Patients treated with HDR brachytherapy monotherapy for prostate cancer were identified in a prospectively maintained, single institution database. Patients with AJCC T-stage ≤ T2b, Gleason score ≤ 7, prostate-specific antigen level ≤ 20 ng/mL, and ≥2 years of follow-up were included.

RESULTS

671 patients were evaluated. 310 patients received 38 Gy in 4 fractions, 129 received 24 Gy in 2 fractions, and 232 received 27 Gy in 2 fractions. Median follow-up was 12.8 years, 10.6 years, and 8.1 years (p < 0.001), respectively. 231 (74.5%), 92 (71.3%), and 81 (34.9%) patients (p < 0.001) had low-risk disease. Rates of acute grade ≥2 GU toxicity were 11.1%, 12.3%, and 25.0% (p = 0.004), while chronic grade ≥2 GU toxicity were 17.0%, 22.6%, and 26.5% (p = 0.06). For low-risk patients, 10-year overall survival (OS), freedom from biochemical failure (ffBF), local control (LC), and freedom from distant metastasis (ffDM) were 86.6%, 93.3%, 97.9%, and 99.3%. For intermediate-risk patients, 10-year OS, ffBF, LC, and ffDM were 89.5%, 82.6%, 90.5%, and 97.4%. Higher PSA, higher Gleason score, perineural invasion, and 24 Gy or 27 Gy treatment schedules were predictors of biochemical failure.

CONCLUSIONS

HDR brachytherapy monotherapy with 38 Gy in 4 fractions was associated with improved long-term ffBF compared with 24 Gy/27 Gy in 2 fractions, without any associated increase in GI or GU toxicity rates.

Assessment of integrated electromagnetic tracking for dwell position monitoring in a clinical HDR brachytherapy setting for prostate cancer

BACKGROUND

Electromagnetic Tracking (EMT) technology has been integrated in a prototype high-dose-rate brachytherapy (HDR-BT) afterloading device. Its potential for dwell position (DP) monitoring has earlier been demonstrated in prostate phantoms. However, its performance for prostate BT in the clinical setting remains to be assessed.

AIM

Assess the reliability and value of EMT measurements in transrectal ultrasound-based (TRUS-based) and computed tomography-based (CT-based) prostate HDR-BT.

METHODS

EMT measurements were conducted on 20 patients undergoing dual-fraction prostate HDR-BT monotherapy. In each treatment fraction an individual TRUS-based or CT-based treatment plan was generated. The measurements were compared to DPs of manually reconstructed needles in those TRUS-based or CT-based treatment plans. An internal reference sensor was also placed in one needle to assess internal movement levels and its potential for movement correction.

RESULTS

For TRUS-based treatments, median Euclidean distances (ED) of 1.00 mm were observed between EMT measurements and manual DP determination. Reference sensor movement was minimal at a median of 0.18 mm. For DPs measured in the CT-room and treatment room, median EDs of 1.60 mm and 2.24 mm compared to CT-based DP determination respectively were observed, indicating the system's ability to detect changes in implant geometry over time and after patient repositioning. Median reference sensor movement of 0.97 mm was observed. Implementing reference sensor-based movement correction led to a significant but small decrease in ED for CT-based treatments.

CONCLUSION

EMT is suitable for TRUS-based prostate HDR-BT quality assurance and error detection. While EMT can identify changes in implant geometry in CT-based prostate HDR-BT treatments, it showed lower accuracy in this setting.

Brachytherapy based microboosting to the dominant intraprostatic lesion in prostate cancer: A systematic review on treatment outcomes and toxicities

PURPOSE

Whether brachytherapy based microboosting of the dominant intraprostatic lesion (DIL) improves outcomes over standard approaches is not known. The purpose of this study is to perform a systematic review on brachytherapy microboosting of the DIL to evaluate clinical outcomes and toxicities with this treatment approach.

MATERIALS AND METHODS

This review was performed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Databases including Pubmed, Embase, and Google Scholar were queried. About 16 studies met our inclusion criteria. These studies reported PSA control and/or toxicities based on standardized scales.

RESULTS

There were 10 studies (two monotherapy, eight combination) that used HDR microboosting on a total of 516 patients. HDR dose (EQD2 assuming alpha/beta of 1.5) to the DIL ranged from 90 to 180 Gy. Most patients were low/intermediate risk. PSA control rates at 5-8 years ranged from 69% to 100%. Acute/late G3-G4 GU/GI toxicities ranged from 0% to 12%. There were six studies (five monotherapy, one combination) that used LDR microboosting on a total of 1041 patients. Studies performed a microboost of 130-150% of the whole gland prescription to the DIL. Most patients were low/intermediate risk. PSA control rates at 5 years ranged from 69% to 98%. Acute/late G3-4 GU/GI toxicities ranged from 0% to 4%.

CONCLUSIONS

Over 1000 patients have been treated with a brachytherapy based microboost in published series. Severe acute/late toxicities appear limited. PSA control rates with more than 5 years of follow-up are limited. Longer-term follow-up is needed to determine ideal utilization of this approach.

ONE SHOT - single shot radiotherapy for localized prostate cancer: 18-month results of a single arm, multicenter phase I/II trial

PURPOSE

To assess in a prospective, multicenter, single-arm phase I/II study the early safety and efficacy profile of single fraction urethra-sparing stereotactic body radiotherapy (SBRT) for men with localized prostate cancer.

MATERIAL AND METHODS

Patients with low- and intermediate-risk localized prostate cancer without significant tumor in the transitional zone were recruited. A single-fraction of 19 Gy was delivered to the prostate, with 17 Gy dose-reduction to the urethra. Intrafraction motion was monitored using intraprostatic electromagnetic transponders with intra-fraction correction of displacements exceeding 3 mm. Genitourinary (GU), gastrointestinal (GI), and sexual toxicity during the first 18 months were evaluated using the CTCAE v4.0 grading scale. Quality of life was assessed using the International Prostate Symptom Score, the Expanded Prostate Cancer Index composite 26 score, and the International Index of Erectile Function score.

RESULTS

Among the 45 patients recruited in 5 centers between 2017 and 2022, 43 received the single fraction without protocol deviations, and 34 had a minimal follow-up of 18 months. The worst GU toxicity was observed at day-5 after SBRT (42.5 % and 20 % with grade 1 and 2, respectively), returning to baseline at week-12 and month-6 (<3% with grade 2), with a 12 % grade 2 flare at month 18. Gl toxicity was mild in the acute phase, with no grade ≥ 2 events (12 % grade 1 at month 6). Grade-3 proctitis was observed in one patient at month 12, with < 3 % grade 2 toxicity at month 18. Mean GU and GI bother scores showed a decline at day 5, a complete recovery at month 6, and a flare between month 12 and 18. Mean PSA dropped from 6.2 ng/ml to 1.2 ng/ml at month 18 and 0.7 ng/ml at month 24. After a median follow-up time of 26 months, 3 biochemical failures (7 %) were observed at month 17, 21 and 30.

CONCLUSIONS

In this multicenter phase I/II trial, we demonstrated that a 19 Gy single-fraction urethra-sparing SBRT is feasible and associated with an acceptable toxicity rate, mostly returning to the baseline at week-12 and with a symptoms flare between months 12 and 18. Longer follow-up is needed to assess the potential long-term adverse effects and the disease control efficacy.