External beam radiation therapy to the prostate is typically delivered after verification of prostatic position with image guidance. Prostate motion can occur during the delivery of each radiation treatment between the time of localization imaging and completion of treatment. The objective of this work is to review the literature on intrafraction motion (IFM) of the prostate during radiation therapy, and offer clinical recommendations on management.
A comprehensive literature review was conducted on prostate motion during prostate cancer radiation therapy. Information was organized around three key clinical questions, followed by an evidence-based recommendation.
IFM of the prostate during radiation therapy is typically ≤3 mm, and is unlikely to compromise prostate dosimetry to a clinically meaningful degree for men treated in a relatively short treatment duration with planning target volume (PTV) margins of ≥3-5 mm. IFM of 5 mm or more has been observed in up to ∼10% of treatment fractions, with limited dosimetric impact related to the infrequency of occurrence and longer fractionation of therapy. IFM can be monitored in continuous or discontinuous fashion with a variety of imaging platforms. Correction of IFM may have the greatest value when tighter PTV margins are desired (such as with stereotactic body radiation therapy or intraprostatic nodule boosting), ultra-hypofractionated courses, or when treatment time exceeds several minutes.
This focused review summarizes literature and provides practical recommendations regarding IFM in the treatment of prostate cancer with external beam radiation therapy.
Practical radiation oncology. 2023 Oct 22 [Epub ahead of print]
Aoi Shimomura, Tianming Wu, Iris Rusu, Amar U Kishan, Alison C Tree, Abhishek A Solanki, Stanley L Liauw
Department of Radiation and Cellular Oncology, University of Chicago Medicine, Chicago IL, USA., Department of Radiation Oncology, Stritch School of Medicine, Cardinal Bernardin Cancer Center, Loyola University Chicago, Maywood IL, USA., Department of Radiation Oncology, University of California, Los Angeles, CA, USA., The Royal Marsden NHS Foundation Trust, Sutton, United Kingdom; Division of Radiotherapy and Imaging, Institute of Cancer Research, Sutton, United Kingdom., Department of Radiation and Cellular Oncology, University of Chicago Medicine, Chicago IL, USA. Electronic address: .