SBRT For Prostate Cancer Research Articles

361: Prostate cancer SBRT: sexual function and radiation dose to penile base structures

361: Prostate cancer SBRT: sexual function and radiation dose to penile base structures

860: A comparative study of single-arc vs dual-arc VMAT techniques in Linac-based prostate cancer SBRT

860: A comparative study of single-arc vs dual-arc VMAT techniques in Linac-based prostate cancer SBRT

1123: Early results of LDR brachytherapy 108 Gy and ultrahypofractionated 5*5 Gy SBRT for prostate cancer

1123: Early results of LDR brachytherapy 108 Gy and ultrahypofractionated 5*5 Gy SBRT for prostate cancer

2589: Hyaluronic acid versus balloon rectal spacers in robotic SBRT for prostate cancer: QoL and toxicity

2589: Hyaluronic acid versus balloon rectal spacers in robotic SBRT for prostate cancer: QoL and toxicity

OC-0626 HDR-BT and SBRT in prostate cancer: results from a prospective phase II trial NCT04523896

OC-0626 HDR-BT and SBRT in prostate cancer: results from a prospective phase II trial NCT04523896

PO-1503 Early clinical evaluation of a GPS-based gating approach during prostate cancer SBRT

PO-1503 Early clinical evaluation of a GPS-based gating approach during prostate cancer SBRT

PO-1885 GPS-based intrafraction prostate motion monitoring and management during prostate cancer SBRT

PO-1885 GPS-based intrafraction prostate motion monitoring and management during prostate cancer SBRT

PD-0573 MR-guided daily adapted SBRT for prostate cancer: Acute and late patient reported outcomes

PD-0573 MR-guided daily adapted SBRT for prostate cancer: Acute and late patient reported outcomes

PO-1454 SBRT for prostate cancer with or without Elective Nodal Irradiation

PO-1454 SBRT for prostate cancer with or without Elective Nodal Irradiation

PO-1484 SBRT for prostate cancer: analysis of CBCT guided radiotherapy and on-line correction

PO-1484 SBRT for prostate cancer: analysis of CBCT guided radiotherapy and on-line correction

1.5T MR-Guided Daily-Adaptive SBRT for Prostate Cancer: Preliminary Report of Toxicity and Quality of Life of the First 100 Patients.

Purpose: The present study reports the preliminary outcomes in terms of adverse events and quality of life in the first 100 patients treated with 1.5T MR-guided daily-adaptive stereotactic body radiotherapy for prostate cancer. Methods: From October 2019 to December 2020, 100 patients, enrolled in a prospective study, received MR-guided SBRT for prostate cancer. Rectal spacer insertion was optional and administered in 37 patients. In total, 32 patients received androgen deprivation therapy in accordance with international guidelines. A prospective collection of data regarding toxicity and quality of life was performed. Results: The median age was 71 years (range, 52-84). The median total dose delivered was 35 Gy (35-36.25 Gy) in five sessions, either on alternate days (n = 25) or consecutive days (n = 75). For acute toxicity, we recorded: seven cases of acute G2 urinary pain and four cases of G2 gastrointestinal events. The median follow-up was 12 months (3-20), recording three late G2 urinary events and one G3 case, consisting of a patient who required a TURP 8 months after the treatment. For gastrointestinal toxicity, we observed 3 G ≥ 2 GI events, including one patient who received argon laser therapy for radiation-induced proctitis. Up to the last follow-up, all patients are alive and with no evidence of biochemical relapse, except for an M1 low-volume patient in distant progression two months after radiotherapy. QoL evaluation reported a substantial resolution of any discomfort within the second follow-up after radiotherapy, with the only exception being sexual items. Notably, after one year, global health items were improved compared to the baseline assessment. Conclusions: This study reports very promising outcomes in terms of adverse events and QoL, supporting the role of 1.5T MR-guided SBRT for prostate cancer. To date, this series is one of the first and largest available in the literature. Long-term results are warranted.

Acute and Late Toxicity of Prostate-Only or Pelvic SBRT in Prostate Cancer: A Comparative Study

<h3>Purpose/Objective(s)</h3> To compare the urinary and gastrointestinal toxicity with or without the inclusion of pelvic nodal regions in patients treated with extreme hypofractionated stereotactic radiotherapy (SBRT) for prostate cancer. <h3>Materials/Methods</h3> Patients treated with definitive SBRT for non-metastatic adenocarcinoma prostate were identified from a prospectively maintained institutional database and details of radiotherapy volume, dose, acute and late adverse effects were analyzed. Symptoms of acute (within 90 days of completing SBRT) and late gastrointestinal and urinary toxicities were graded using CTCAE version 5.0. Each symptom was scored according to the worst reported grading during treatment and follow-up period. ‘Non-infective cystitis' was considered as ‘urinary toxicity' because it encompasses all other urinary symptoms. Cumulative toxicity rates between prostate-only SBRT (PO-SBRT) and whole pelvic SBRT (WP-SBRT) were compared using chi-square test. <h3>Results</h3> Total 220 patients were analyzed (PO-SBRT=118, WP-SBRT=102), with most having locally advanced disease (PO-SBRT 60% high risk, 40% intermediate risk; WP-SBRT 79% node positive, 21% high risk). Median SBRT dose was 36.25Gy (IQR 35-36.25) to the prostate (EQD2=90.6Gy, a/b=1.5Gy) and simultaneous integrated 25Gy to the pelvis (EQD2=46.3Gy) in five fractions on alternate days. No grade 3-4 acute toxicities were observed except one grade 3 urinary obstruction (PO-SBRT). WP-SBRT was associated with significantly higher grade 2 acute GI toxicity (29.4% vs 14.7%, p=0.008), acute proctitis (23.5% vs 11.2%, p=0.016) and acute diarrhea (13.7% vs 1.7%, p=0.001). At a median follow-up of 28 months, grade 2 late urinary toxicity was significantly higher with WP-SBRT (45.6% vs 25.0%, p=0.003), while gastrointestinal toxicity was similar in both the groups (18.9% vs 13.4% p=0.1). Grade 3 late toxicities were low in both the groups (urinary 2.5%, gastrointestinal 1%). <h3>Conclusion</h3> WP-SBRT is associated with significant increase in acute GI and late urinary toxicities compared to PO-SBRT. Prospective validation of these findings is ongoing.

PO-1405 Sbrt in prostate cancer: a feasibility and safety annalysis

PO-1405 Sbrt in prostate cancer: a feasibility and safety annalysis

PO-1381 SBRT in prostate cancer: annalysis of CBCT guided radiotherapy and on-line correction

PO-1381 SBRT in prostate cancer: annalysis of CBCT guided radiotherapy and on-line correction

PO-1401 MR-guided adaptive versus CT-guided SBRT for prostate cancer: where is cost-benefit balance?

PO-1401 MR-guided adaptive versus CT-guided SBRT for prostate cancer: where is cost-benefit balance?

PD-0577 Patient-reported acute urinary toxicity after daily adaptive MR-guided SBRT for prostate cancer

PD-0577 Patient-reported acute urinary toxicity after daily adaptive MR-guided SBRT for prostate cancer

PD-0575 Toxicity and QoL report of 1.5T MR-guided SBRT for prostate cancer in the first 100 patients

PD-0575 Toxicity and QoL report of 1.5T MR-guided SBRT for prostate cancer in the first 100 patients

P92 - Modeling prolonged SBRT for prostate cancer

P92 - Modeling prolonged SBRT for prostate cancer

Early Outcomes and Decision Regret Using PSMA/MRI-Guided Focal Boost for Prostate Cancer SBRT

PurposeStereotactic body radiation therapy (SBRT) is a recognized treatment for low- and intermediate-risk prostate cancer, with 36.25 Gy in 5 fractions the most commonly used regimen. We explored the preliminary efficacy, patient recorded toxicity, and decision regret in intermediate- and high-risk prostate cancer receiving SBRT with prostate-specific membrane antigen (PSMA)/magnetic resonance imaging (MRI) guided focal gross tumor volume boost to 45 Gy. Methods and MaterialsBetween July 2015 and June 2019, 120 patients received SBRT across 2 institutions with a uniform protocol. All patients had fiducial markers and hydrogel, MRI and PSMA positron emission tomography (PET) scan. All patients received a questionnaire asking the degree of urinary, bowel, and sexual bother experienced at set time points, including questions about treatment choice and decision regret. ResultsOne hundred twelve of 120 patients consented. Their median age was 72 years and median follow-up was 2.3 years. As per National Comprehensive Cancer Network guidelines, 78% had intermediate risk and 20% high risk. Androgen deprivation was combined with radiation in 6 patients. Most patients (74%) reported that receiving SBRT significantly influenced their choice of treatment. Five men (4%) expressed “quite a lot” (n = 4) or “very much” regret (n = 1) regarding their choice of treatment, while 89% expressed “no regret.” Similar to pretreatment levels, “quite a lot” or “very much” urinary or bowel bother was expressed in 8% and 6% of patients, respectively. Two patients experienced nadir +2 biochemical failure, both found to have bone metastases. A third patient underwent PSMA PET at nadir +1.7 and had disease at the penile bulb, which was out of field. Three year estimated freedom from biochemical failure was 99% for intermediate and 85% for high-risk groups. ConclusionsWe have demonstrated promising efficacy and low toxicity with PSMA/MRI-guided SBRT focal boost. Less than 5% of patients expressed significant decision regret for their choice of treatment.

Treatment outcome and compliance to dose-intensified linac-based SBRT for unfavorable prostate tumors using a novel real-time organ-motion tracking

Purpose/objectivesTo report preliminary data on treatment outcome and compliance to dose-intensified organ sparing SBRT for prostate cancer using a novel electromagnetic transmitter-based tracking system (RayPilot® System) to account for intra-fractional organ motion.Material/methodsThirteen patients with intermediate unfavorable (9) and selected high-risk (4) prostate cancer underwent dose-escalated SBRT in 4 or 5 fractions (BED1.5 = 279 Gy and 253 Gy, respectively). The VMAT treatment consisted in two 6FFF or 10FFF full arcs optimized to have the 95% isodose covering at least 95% of the PTV (2 mm isotropic expansion of the CTV). Whenever the real-time tracking registered a displacement that exceeded 2 mm during the setup and/or the beam delivery, the treatment was interrupted and the prostate motion was promptly corrected. The incidence of treatment-related genitourinary (GU) and gastrointestinal (GI) toxicity, patient QoL and PSA outcomes were computed from the start of treatment to the last follow-up date.ResultsAll patients completed the treatment in the expected time (10.2 +/− 4.2 minutes) and their compliance to the procedure was excellent. No clinically significant acute Grade 2 or higher GI (rectal) and GU side effects were observed within 90 days from the treatment completion. The median IPSS increased from 8 at baseline to 12 one-month after treatment and settled to 6 at 3 months. EPIC-26 scores in the urinary domain decreased from a median baseline of 86 pre-treatment to 79 at one-month and returned to baseline at a later timepoint (median score of 85 at 3 months). EPIC-26 scores in the bowel domains did not show significant changes within 3 months following RT. The prostate was found within 1 mm from its initial position in 78% of the beam-on time, between 1 and 2 mm in 20%, and exceeded 2 mm only in 2%, after correction for motion which was performed in 45% of the fractions, either during setup or beam delivery.ConclusionsOur preliminary findings show that dose intensified SBRT for unfavorable prostate tumors does not come at the cost of an increased toxicity, provided that a reliable technique for real time prostate monitoring is ensured. Fast FFF beams contributed to reduce intra-fractional motion. These observations need to be confirmed on a larger scale and a longer follow up.