A pilot study of the use of MRI scans to plan the escalation of radiotherapy dose to the dominant tumour(s) within the prostate

Summary

Prostate cancer is currently the most common cancer in men and is often treated using high-energy external beam radiotherapy (EBRT). However, the treatment results of EBRT for advanced prostate cancer patients need to improve as current five-year cancer recurrence rates are approximately 35%. Randomized trials demonstrate that a higher dose to the entire prostate improves prostate cancer control. However this can be harmful to surrounding tissues and increase side effects.

Dose Painting, where a standard radiotherapy dose is given to the whole prostate and an additional boost dose is given to localised small areas inside the prostate containing high numbers of cancer cells (dominant tumours), may improve treatment results. This in turn may reduce five-year cancer recurrence rates without significantly increasing side effects. Recent studies suggest that Magnetic Resonance Imaging (MRI) can locate the dominant tumours within the prostate. This project will determine whether: a) dominant tumours can be located using MRI; b) a treatment plan can be created for the radiotherapy boost dose and c) whether the resulting planned boost dose could be safely delivered to dominant tumours without damaging healthy tissues.

By combining MRI and treatment planning techniques, we can determine the feasibility of delivering an additional boost dose of radiotherapy specifically to the dominant tumours in the prostate thus improving local control of the cancer, sparing healthy tissues and reducing side effects. The patients in this pilot will not receive the additional radiotherapy boost to the dominant tumour as this is a planning study only.

Outputs

Steve W. Blake, Alison Stapleton, Andrew Brown, Sian Curtis, Janice Ash-Miles, Emma Dennis, Susan Masson, Dawn Bowers, Serena Hilman. A study of the clinical, treatment planning and dosimetric feasibility of dose painting in external beam radiotherapy of prostate cancer. phiRO, 15 (2020), pp. 66-71.  https://doi.org/10.1016/j.phro.2020.07.005