The Proton Therapy Center conducted a study, the results of which were published in the International Journal of Radiation Oncology, Biology and Physics. The study, called Ultrahypofractionated Proton Radiation Therapy in the Treatment of Low and Intermediate-Risk Prostate Cancer-5-Year Outcomes, between January 2013 and March 2016 followed 284 patients treated using intensity modulated proton therapy (IMPT) with an ultrahypofractionated schedule (36.25 GyE in 5 fractions) using pencil beam scanning (PBS) proton radiotherapy. The median treatment time was 9 days.
Course of Study
Five patients were immediately lost from follow-up and thus were excluded from analysis. Data for 279 patients were prospectively collected and analyzed with a median follow-up time of 56.5 (range, 3.4-87.5) months. The mean age at time of treatment was 64.5 (40.1-85.7) years, and the median prostate-specific antigen (PSA) value was 6.35 μg/L (0.67-17.3 μg/L).
A total of 121 (43.4%) patients had low-risk, 125 patients (44.8%) had favorable, and 33 (11.8%) unfavorable intermediate-risk cancer. In addition, 49 (17.6%) patients underwent neoadjuvant hormonal therapy, and no patients had adjuvant hormonal therapy. bDFS and late toxicity profiles were evaluated.
Results
The median treatment time was 9 days (range, 7-18 days). The 5-year bDFS was 96.9%, 91.7%, and 83.5% for the low, favorable, and unfavorable intermediate-risk group, respectively.
Late toxicity (Common Terminology Criteria for Adverse Events v.4) was as follows: gastrointestinal: grade 1, 62 patients (22%), grade 2, 20 patients (7.2%), and grade 3, 1 patient (0.36%); genitourinary: grade 1, 80 patients (28.7%), grade 2, 14 patients (5%), and grade 3, 0 patients.
PSA relapse was observed in 17 patients (6.1%), and lymph node or bone recurrence was detected in 11 patients. Four (1.4%) local recurrences were detected. Nine patients (3.2%) died of causes unrelated to prostate cancer. No deaths related to prostate cancer were reported.
Conclusion
Ultrahypofractionated proton radiation therapy using the PBS technique is effective and comparable to other fractionation regimens with long-term bDFS, but with minimal severe long-term gastrointestinal (GI) and genitourinary (GU) toxicity. It was shown that 5 years after treatment, 97% of patients with low-risk prostate cancer were cured and did not have an increase in PSA. In patients with moderate prostate cancer, we can state that a total of 90% of them were cured.
Purchase the book via the link below.
Purchase the book via the link below.
