Dataset Information

Single-Center Evaluation of Treatment Success Using Two Different Protocols for MRI–Guided Transurethral Ultrasound Ablation of Localized Prostate Cancer

ABSTRACT:

Objectives

To assess differences in 24-month oncologic and functional outcomes in men with low to intermediate-risk prostate cancer treated with MRI-guided transurethral ultrasound ablation (TULSA) using intentionally conservative versus intensified treatment parameters.

Patients and Methods

Patients from a single center involved in two multicenter trials were included in this analysis. This included 14 of 30 patients with Gleason 3 + 3 from a Phase I study using intentionally conservative treatment parameters, and 15 of 115 patients with Gleason ≤ 3 + 4 from a pivotal study using intensified parameters. Follow-up data compared across these cohorts included 12-month biopsy and MRI for all patients, and 24-month PSA, micturition and quality of life (IIEF, IPSS, IPSS-QOL). The prognostic value of baseline parameters and PSA kinetics on 12-month histological recurrence was evaluated by logistic regression.

Results

12-month biopsy revealed clinically significant residual disease in 4 (29%) and 2 (14%) patients from the Phase I and pivotal studies, respectively. PSA nadir was 0.7 ng/ml for Phase I and 0.5 ng/ml for pivotal study patients. Patient age at diagnosis, use of MRI fusion/systematic prostate biopsy, number of obtained cores at initial biopsy, PSA course, and PSA nadir were identified as prognostic factors for treatment success. All but one patient from each cohort maintained erection firmness sufficient for penetration. No cases of pad use were reported at 24 months. There were no Grade 4 or higher adverse events, and no late toxicity related to the procedure.

Conclusion

Two-year follow-up demonstrated the efficacy of TULSA for the treatment of localized prostate cancer, and the durability of PSA and functional outcomes. Intensifying treatment parameters in the pivotal trial had no impact on safety or functional outcomes through 24 months, while reducing the recurrence rate for clinically significant disease. Careful patient selection by MRI fusion/systematic prostate biopsy and adequate follow-up through routine 12-month biopsy are recommended.

SUBMITTER: Hatiboglu G

PROVIDER: S-EPMC8579125 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundUp to half of all men who undergo primary radiotherapy for localized prostate cancer (PCa) experience local recurrence.ObjectiveTo evaluate the safety and early functional and oncological outcomes of salvage magnetic resonance imaging-guided transurethral ultrasound ablation (sTULSA) for men with localized radiorecurrent PCa.Design setting and participantsThis prospective, single-center phase 1 study (NCT03350529) enrolled men with biopsy-proven localized PCa recurrence after radiotherapy. Multiparametric magnetic resonance imaging (mpMRI) and 18F prostate-specific membrane antigen-1007 (18F PSMA-1007) positron emission tomography (PET)-computed tomography (CT) were used to confirm organ-confined disease localization. Patients underwent either whole-gland or partial sTULSA, depending on their individual tumor characteristics.Outcome measurements and statistical analysisPatients were followed at 3-mo intervals. Adverse events (AEs, Clavien-Dindo scale), functional status questionnaires (Expanded Prostate Cancer Index [EPIC]-26, International Prostate Symptom Score, International Index of Erectile Function-5), uroflowmetry, and prostate-specific antigen (PSA) were assessed at every visit. Disease control was assessed at 1 yr using mpMRI and 18F-PSMA-1007 PET-CT, followed by prostate biopsies.Results and limitationsEleven patients (median age 69 yr, interquartile range [IQR] 68-74) underwent sTULSA (3 whole-gland, 8 partial sTULSA) and have completed 12-mo follow-up. Median PSA was 7.6 ng/ml (IQR 4.9-10) and the median time from initial PCa diagnosis to sTULSA was 11 yr (IQR 9.5-13). One grade 3 and three grade 2 AEs were reported, related to urinary retention and infection. Patients reported a modest degradation in functional status, most significantly a 20% decline in the EPIC-26 irritative/obstructive domain at 12 mo. A decline in maximum flow rate (24%) was also observed. At 1 yr, 10/11 patients were free of any PCa in the targeted ablation zone, with two out-of-field recurrences. Limitations include the nonrandomized design, limited sample size, and short-term oncological outcomes.ConclusionssTULSA appears to be safe and feasible for ablation of radiorecurrent PCa, offering encouraging preliminary oncological control.Patient summaryWe present safety and 1-yr functional and oncological outcomes of magnetic resonance imaging-guided transurethral ultrasound ablation (TULSA) as a salvage treatment for local prostate cancer recurrence after primary radiation. Salvage TULSA is safe and shows the ability to effectively ablate prostate cancer recurrence, with acceptable toxicity.

Project description:This work explored an elementwise approach to model transcranial MRI-guided focused ultrasound (TcMRgFUS) thermal ablation, a noninvasive approach to neurosurgery. Each element of the phased array transducer was simulated individually and could be simultaneously loaded into computer memory, allowing for rapid (~2.5 s) calculation of the pressure field for different phase offsets used for beam steering and aberration correction. We simulated the pressure distribution for 431 sonications in 32 patients, applied the phase and magnitude values used during treatment, and estimated the resulting temperature rise. We systematically varied the relationship between CT (computerized tomography)-derived skull density and the acoustic attenuation and sound speed to obtain the best agreement between the predictions and MR temperature imaging (MRTI). The optimization was validated with simulations of 396 sonications from 40 additional treatments. After optimization, the predicted and measured heating agreed well (R2: 0.74 patients 1-32; 0.71 patients 33-72). The dimensions and obliquity of the heating in the simulated temperature maps were correlated with the MRTI (R2: 0.62, 0.74, respectively), but the measured heating was more spatially diffuse. The energy needed to achieve ablation varied by an order of magnitude (3.3-36.1 kJ). While this elementwise approach required more computation time up front (the combined simulation matrices were approximately 4.6 times higher than a single large simulation), it could be performed in parallel on a computing cluster. It allows for rapid calculation of the three-dimensional heating at the focus for different phase and magnitude values on the array. We also show how this approach can be used to optimize the relationship between CT-derived skull density and acoustic properties. While the relationships found here need further validation in a larger patient population, these results demonstrate the promise of this approach to model TcMRgFUS.

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Project description:We report the results of a retrospective analysis of localized prostate cancer (LPCa) treated with transperineal ultrasound image-guided radiotherapy (TPUS-IGRT). A total of 124 patients (median age: 74 y, 46-84 y) with LPCa who underwent TPUS-IGRT (Clarity Autoscan system; CAS, Elekta; Stockholm, Sweden) between April 2016 and October 2021 for curative/after hormone induction were enrolled. The number of patients by risk (National Comprehensive Cancer Network 2019) was 7, 25, 42, and 50 for low (LR), good intermediate (good IR), poor intermediate (poor IR), and high (HR)/very high (VHR), respectively. Ninety-five patients were given neoadjuvant hormonal therapy. The planning target volume margin setting was 3 mm for rectal in most cases, 5-7 mm for superior/inferior, and 5 mm for anterior/right/left. The principle prescribed dose is 74 Gy (LR), 76 Gy (good IR), and 76-78 Gy (poor IR or above). CAS was equipped with a real-time prostate intrafraction monitoring (RTPIFM) system. When a displacement of 2-3 mm or more was detected, irradiation was paused, and the patients were placed on standby for prostate reinstatement/recorrection. Of the 3135 fractions in 85 patients for whom RTPIFM was performed, 1008 fractions (32.1%) were recorrected at least once after starting irradiation. A total of 123 patients completed the radiotherapy course. The 5-year overall survival rate was 95.9%. The 5-year biological prostate-specific antigen relapse-free survival rate (bPFS) was 100% for LR, 92.9% for intermediate IR, and 93.2% for HR/VHR (Phoenix method). The 5-year late toxicity rate of Grade 2+ was 7.4% for genitourinary (GU) and 6.5% for gastrointestinal (GI) organs. Comparing the ≤ 76 Gy group to the 78 Gy group for both GU and GI organs, the incidence was higher in the 78 Gy group for both groups. These results suggest that TPUS-IGRT is well tolerated, as the bPFS and incidence of late toxicity are almost comparable to those reported by other sources of image-guided radiotherapy.

Project description:PurposeIn this study, the efficacy of transurethral prostate ablation in the presence of silica-shell ultrasound-triggered phase-shift emulsions (sUPEs) doped with MR contrast was evaluated. The influence of sUPEs on MR imaging assessment of the ablation zone was also investigated.MethodssUPEs were doped with a magnetic resonance (MR) contrast agent, Gd2 O3 , to assess ultrasound transition. Injections of saline (sham), saline and sUPEs alone, and saline and sUPEs with Optison microbubbles were performed under guidance of a prototype interventional MRI navigation platform in a healthy canine prostate. Treatment arms were evaluated for differences in lesion size, T1 contrast, and temperature. In addition, non-perfused areas (NPAs) on dynamic contrast-enhanced (DCE) MRI, 55°C isotherms, and areas of 240 cumulative equivalent minutes at 43°C (CEM43 ) dose or greater computed from MR thermometry were measured and correlated with ablated areas indicated by histology.ResultsFor treatment arms including sUPEs, the computed correlation coefficients between the histological ablation zone and the NPA, 55°C isotherm, and 240 CEM43 area ranged from 0.96-0.99, 0.98-0.99, and 0.91-0.99, respectively. In the absence of sUPEs, the computed correlation coefficients between the histological ablation zone and the NPA, 55°C isotherm, and 240 CEM43 area were 0.69, 0.54, and 0.50, respectively. Across all treatment arms, the areas of thermal tissue damage and NPAs were not significantly different (P = 0.47). Areas denoted by 55°C isotherms and 240 CEM43 dose boundaries were significantly larger than the areas of thermal damage, again for all treatment arms (P = 0.009 and 0.003, respectively). No significant differences in lesion size, T1 contrast, or temperature were observed between any of the treatment arms (P > 0.0167). Lesions exhibiting thermal fixation on histological analysis were present in six of nine insonations involving sUPE injections and one of five insonations involving saline sham injections. Significantly larger areas (P = 0.002), higher temperatures (P = 0.004), and more frequent ring patterns of restricted diffusion on ex vivo diffusion-weighted imaging (P = 0.005) were apparent in lesions with thermal fixation.ConclusionsT1 contrast suggesting sUPE transition was not evident in sUPE treatment arms. The use of MR imaging metrics to predict prostate ablation was not diminished by the presence of sUPEs. Lesions generated in the presence of sUPEs exhibited more frequent thermal fixation, though there were no significant changes in the ablation areas when comparing arms with and without sUPEs. Thermal fixation corresponded to some qualitative imaging features.