Transcript:
CancerNetwork: How did biochemical relapse-free survival and overall disease control compare across the intermediate-, high-, and very high–risk cohorts in your study of intensity-modulated proton therapy?
Fagundes: When we talk about biochemical disease control, we are talking about patients with prostate cancer whom we treat and whose [prostate-specific antigen (PSA)] goes down and does not come back up. Biochemical recurrence is defined as a rise in PSA that may be caused by recurrence of cancer. In a patient who is treated successfully, we expect the PSA to remain low. In patients with favorable intermediate- or unfavorable intermediate-risk [disease], the results are generally better, with a better than 90% chance of remaining free of disease recurrence. In patients with high-risk or very high–risk disease, the recurrence risk may be in the range of 10% to 20%.
This is not a comparative study [against patients who did not receive protons]. This study reports on WCI’s experience treating patients with prostate cancer with proton therapy between 2018 and December 2023. This is the first report of the initial 404 patients, all of whom were treated with proton therapy.
What is interesting is that in patients with high-risk and very high–risk [disease], a substantial number, the majority, also received pelvic nodal radiation as part of their treatment. That is because these patients have an increased risk of cancer spreading to the lymph nodes. Proton therapy can treat the pelvic lymph nodes without increasing the risk of [adverse] effects like diarrhea. The treatment is safer in that sense, and we are giving the same effective dose as you would with conventional radiation, which is intensity-modulated photon radiation.
Reference
Fagundes MA, Hassan H, Rodrigues M-A, et al. Intensity modulated proton therapy (IMPT) for localized prostate cancer: disease control outcomes in intermediate to very-high risk patients. Presented at: 2026 ASTRO Annual Meeting; September 26-30, 2026; Boston, MA. Abstract PQA 06.
