Dose to the dominant intraprostatic lesion using HDR vs. LDR monotherapy: A Phase II randomized trial

Tissaverasinghe, S.; Crook, Juanita; Bachand, François; Batchelar, Deidre; Hilts, Michelle; Araujo, Cynthia; Anderson, Danielle; Bainbridge, Terry C.; Farnquist, Brenda

doi:10.1016/j.brachy.2019.01.006

Cited by 10 publications

(8 citation statements)

References 40 publications

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“…When boosting mp-MRI-identified DILs using HDR brachytherapy with an inverse planning optimiser, Mason et al 15 achieved an increase in DIL D90 of 16% and in DIL V150 of 48·6% for DILs with a median volume of 1·9 cm 3 . Tissaverasinghe et al 16 achieved a DIL D90 of 151% of the prescription dose for LDR monotherapy patients where the average BV was 1·9 cm 3 . We boosted a larger volume of the prostate (median: 6·22 cm 3 ) than these cases and therefore would not be able to achieve as high a boost without exceeding urethra and rectum constraints and risking increased toxicity.…”

Section: Discussionmentioning

confidence: 99%

Single- and dual-source-strength focal boost planning in low-dose-rate prostate brachytherapy: feasibility study

et al. 2023

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Introduction: This study investigates the dose escalation to dominant intra-prostatic lesions (DILs) that is achievable using single-source-strength (SSS) and dual-source-strength (DSS) low-dose-rate (LDR) prostate brachytherapy and a sector-based plan approach. Methods: Twenty patients were retrospectively analysed. Image registration and planning were undertaken using VariSeed v9·0. SSS and DSS boost plans were produced and compared to clinical plans. Dosimetric robustness to seed displacement for SSS and DSS plans was compared to clinical plans using Monte Carlo simulations. Results: Fourteen out of 20 patients had DIL identifiable on magnetic resonance imaging. Median increase in sector D90 of 27% (p < 0·0001) and sector V150 of 31% (p < 0·0001) was achieved with SSS planning without exceeding local rectum and urethra dose constraints. DSS plans achieved dose distributions not statistically significantly different from the SSS plans with a median of eight fewer seeds and two fewer needles. SSS and DSS plan sensitivity to random seed displacement was similar to the clinical plans. Conclusions: Treatment planning using VariSeed to produce SSS and DSS focal boost plans is feasible for LDR prostate brachytherapy to achieve a median escalation in sector D90 of 27% without exceeding local urethral and rectal constraints. SSS and DSS plan dosimetric robustness was similar to clinical plan dosimetric robustness.

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Section: Discussionmentioning

confidence: 99%

Single- and dual-source-strength focal boost planning in low-dose-rate prostate brachytherapy: feasibility study

et al. 2023

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“…In 50% of the patients in this study, the dose limiting organs were the urethra and the urethra_PRV. This was highly influenced by the location of the DIL and its proximity to the urethra [ 29 ]. The median boost dose was 45 Gy for anterior tumours, and 50 Gy in posterior tumours.…”

Section: Discussionmentioning

confidence: 99%

Simultaneous integrated boost (SIB) to dominant intra-prostatic lesions during extreme hypofractionation for prostate cancer: the impact of rectal spacers

et al. 2022

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Purpose Boosting dominant intra-prostatic lesions (DILs) has the potential to increase the therapeutic ratio in prostate cancer radiotherapy. In this study, employing 5-fraction stereotactic ablative radiotherapy (SABR) volumetric modulated arc therapy (VMAT) to deliver 40 Gy to the prostate clinical target volume (CTV) while boosting the DIL up to 50 Gy was evaluated for patients before and after rectal spacer insertion. Materials and methods 24 Computed Tomography (CT) scans of 12 prostate cancer patients with unfavourable intermediate or high risk prostate cancer were employed in this study. At least two treatment plans were generated for each patient to compare pre- and post-spacer insertion plans. Plans were evaluated for target coverage, organs-at-risk doses, and the achievable boost dose level. Results The CTV coverage was significantly better in plans with a spacer, V40Gy 98.4% versus 97.0% (p = 0.012). Using spacers significantly reduced rectal dose in all 12 patients in this study. It was possible to boost DIL to 50 Gy to without violating dose constraints in 6 of 12 patients and to 47.5 Gy in 3 patients post-spacer insertion. For 3 patients (25%) it was not possible to boost DIL above 45 Gy even with a spacer in situ. Without a spacer, for 6 patient (50%) clinically acceptable plan were only achieved when the DIL dose was lowered to 45 Gy. In five of these 6 patients the dose limiting structure was the urethra (urethra planning risk volume V45Gy [cc] ≤ 0.1 cc constraint). Conclusions Clinically acceptable plans for 5 fraction SABR, 40 Gy to the prostate CTV, with a SIB to DIL (45–50 Gy) were achieved. The boost dose achieved was DIL location dependent and primarily affected by DIL’s proximity to the urethra. Compared to plans before spacer insertion, higher DIL dose were achieved with spacer in situ for 25% of the patients. Moreover, significant reduction in rectal dose and better target coverage were also achieved for all patients with spacers in situ.

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“…First, strategies need to be developed for mitigating toxicities associated with LDR brachytherapy boost. Imaging technologies, such as multiparametric magnetic resonance imaging (mpMRI), may play an important role in dose escalation of dominant intraprostatic lesions ( 114 ), while safely sparing organs at risk associated with toxicity and/or adverse quality of life after brachytherapy such as the bladder neck ( 104 ), external urethral sphincter ( 105 , 115 ), and rectum ( 116 ). Second, brachytherapy boost should be offered only to selected group of patents with UIR and HR disease.…”

Section: Discussionmentioning

confidence: 99%

Low dose rate brachytherapy for primary treatment of localized prostate cancer: A systemic review and executive summary of an evidence-based consensus statement

et al. 2021

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Dose to the dominant intraprostatic lesion using HDR vs. LDR monotherapy: A Phase II randomized trial

Cited by 10 publications

References 40 publications

Single- and dual-source-strength focal boost planning in low-dose-rate prostate brachytherapy: feasibility study

Single- and dual-source-strength focal boost planning in low-dose-rate prostate brachytherapy: feasibility study

Simultaneous integrated boost (SIB) to dominant intra-prostatic lesions during extreme hypofractionation for prostate cancer: the impact of rectal spacers

Low dose rate brachytherapy for primary treatment of localized prostate cancer: A systemic review and executive summary of an evidence-based consensus statement

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