Prostate stereotactic body radiotherapy (SBRT) can be delivered using magnetic resonance imaging-guided radiotherapy (MRgRT) with the aim of increased precision and reduced toxicity. The overall treatment time (OTT) for SBRT varies, ranging from daily fractions to once-weekly schedules. However, it is unclear whether OTT affects clinical outcomes when using MRgRT. The aim of this study was to establish whether OTT impacts toxicity, quality of life (QoL), and prostate-specific antigen (PSA) control in prostate MRgRT.
For this study, outcomes from the Multi-OutcoMe EvaluatioN of radiation Therapy Using the MR-Linac (MOMENTUM) study were utilised (NCT04075305). Patients with localised prostate cancer receiving 36.25 Gy to 40 Gy in five fractions, of whom OTT was available, were analysed. Physician-reported Common Terminology Criteria for Adverse Event (CTCAE) toxicity, patient-reported outcomes (PROs) and PSA dynamics were collected at baseline and at three, six, twelve, and 24 months after MRgRT. Univariate ordinal logistic regression and mixed model analysis were performed to study the impact of OTT on changes in genitourinary (GU) and gastrointestinal (GI) toxicity, and QoL and PSA levels compared to baseline, respectively.
A total of 858 patients were included with a median OTT of 14 days, ranging from five to 47 days. Excluding erectile function, no grade ≥3 GU or GI toxicity was reported. The OTT was not associated with acute or late GU toxicity (odds ratio [OR]: 0.97 [95% confidence interval [CI]: 0.92-1.02]; P = 0.21 and OR 0.99 [95% CI: 0.94-1.05]; P = 0.83) or acute and late GI toxicity (OR 0.89 [95% CI: 0.79-1.00]; P = 0.05 and OR 0.99 [95% CI: 0.92-1.07]; P = 0.83). In addition, OTT had no apparent impact on QoL scores and PSA kinetics.
This study suggests that OTT, generally between 8 and 18 days, in five-fraction MRgRT for prostate cancer does not affect GU and GI toxicity, QoL and PSA control. Clinicians should consider discussing OTT with patients as this will facilitate treating patients to the time frame that suits them best, reducing the impact of treatment on their QoL, whilst also allowing flexibility for busy departments.
Clinical oncology (Royal College of Radiologists (Great Britain)). 2026 Feb 06 [Epub ahead of print]
R L Westley, L A Daamen, F R Teunissen, D Vesprini, A Choudhury, F J Pos, H M Verkooijen, C D Fuller, S Choi, W A Hall, J R N van der Voort van Zyp, J P Christodouleas, A C Tree
Department of Radiotherapy, The Royal Marsden NHS Foundation Trust, London, United Kingdom; Division of Radiotherapy and Imaging, The Institute of Cancer Research, Sutton, United Kingdom., Division of Imaging and Oncology, University Medical Center Utrecht, Utrecht, the Netherlands., Department of Radiotherapy, Radboud University Medical Center, Nijmegen, the Netherlands., Department of Radiation Oncology, Sunnybrook Health Sciences Centre-Odette Cancer Centre, Toronto, Ontario, Canada., Department of Clinical Oncology, The University of Manchester, Manchester, United Kingdom., Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, Netherlands., Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, USA., Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA., Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands., Elekta AB, Stockholm, Sweden; Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, USA.