No date

Session Item

Prostate

Session Code: 6016

Session Type: Digital Poster

Track: Clinical

MR-guided SBRT for localized prostate cancer: the first results from the MOMENTUM study

Frederik Teunissen, The Netherlands

Presentation Number: PO-1374

Abstract

Abstract Title:

MR-guided SBRT for localized prostate cancer: the first results from the MOMENTUM study

Authors:

Frederik Teunissen¹, Thomas Willigenburg¹, Alison Tree², William Hall³, Seungtaek Choi⁴, Ananya Choudhury^5,6, John Christodouleas^7,8, Johannes de Boer¹, Eline de Groot-van Breugel¹, Linda Kerkmeijer^9,1, Floris Pos¹⁰, Danny Vesprini¹¹, Helena Verkooijen¹², Jochem van der Voort van Zyp¹

¹University Medical Center Utrecht, Radiation Oncology, Utrecht, The Netherlands; ²The Royal Marsden NHS Foundation Trust and the Institute of Cancer Research, Urological Oncology, London, United Kingdom; ³Medical College of Wisconsin, Radiation Oncology, Milwaukee, USA; ⁴The University of Texas MD Anderson Cancer Center, Radiation Oncology, Houston, USA; ⁵University of Manchester, Division of Cancer Sciences, Manchester, United Kingdom; ⁶The Christie NHS Foundation Trust, Manchester Academic Health Sciences Centre, Clinical Oncology, Manchester, United Kingdom; ⁷University of Pennsylvania, Radiation Oncology, Philadelphia, USA; ⁸Elekta AB, Radiation Oncology, Stockholm, Sweden; ⁹Radboud University Medical Center, Radiation Oncology, Nijmegen, The Netherlands; ¹⁰Antoni van Leeuwenhoek Hospital and The Netherlands Cancer Institute, Radiation Oncology, Amsterdam, The Netherlands; ¹¹Sunnybrook Health Sciences Centre, Radiation Oncology, Toronto, Canada; ¹²University Medical Center Utrecht, Imaging and Oncology Division, Utrecht, The Netherlands

Show Affiliations

Purpose or Objective

Magnetic resonance (MR) guided adaptive radiotherapy (MRgRT) is a new technique for treatment of localized prostate cancer (PCa). MR-guided linear accelerator (MR-Linac) systems have been implemented in radiotherapy departments around the world. However, the theoretical benefits of MRgRT still need to be confirmed in clinical practice. We report the short-term outcomes for the first PCa patients treated within an international consortium on a 1.5T MR-Linac system with ultrahypofractionated radiotherapy.

Material and Methods

Patients treated with 5x7.25 Gray were identified within the registry. Prostate specific antigen (PSA), Common Terminology Criteria for Adverse events (CTCAE) and patient reported outcome (PRO) using the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ)-PR25, EORTC QLQ-C30 and the EuroQol EQ5D-5L were prospectively recorded at baseline and at 3 and 6 months follow-up (FU). Descriptive and pairwise comparative statistics were conducted.

Results

One-hundred-and-fifty-six consecutive patients with localized PCa (13.2% low-, 77.2% intermediate-, and 9.6% high-risk [National Comprehensive Cancer Network risk groups]) were included. Thirty-one patients (19.9%) received neoadjuvant androgen deprivation therapy (ADT). A significant decline of PSA in non-ADT patients was observed between baseline (median: 7.8 ng/mL), 3 months FU (median: 2.7 ng/mL) and 6 months FU (median: 1.7 ng/mL) (p<0.001). No grade ≥3 genitourinary (GU) or gastrointestinal (GI) toxicity was reported (table). No significant deterioration of PRO scores were observed. The percentage of men reporting no difficulty getting or maintaining an erection remained constant throughout FU (44.4% at baseline, 40.0% at 3 months FU, and 42.9% at 6 months FU).

Table: Clinician-reported toxicity using the CTCAE

The highest grade of a given toxicity that occurred in a time period (3 months FU=0 to 3 months after treatment; 6 months FU=3 to 6 months after treatment). Data available: baseline=68/156 patients; 3 months FU=39/147 patients; 6 months FU=20/124 patients

Conclusion

Ultrahypofractionated 1.5T MR-Linac treatment of localized PCa is effective and safe (no grade ≥3 GU or GI toxicity). In the first 6 months following treatment, patients reported stable erectile function. No significant deterioration of PROs at 3- and 6-months FU was observed.