To Örebro University

Hypofractionated radiotherapy (RT), including high dose rate brachy-therapy (HDR-BT) is a theoretically beneficial treatment option for curable prostate cancer. Our studies aimed to contribute to the growing body of results on the effectiveness and safety of HDR-BT both as monotherapy and as a boost in combination with external beam radiation therapy (EBRT).

In paper I, 229 patients (low- and intermediate-risk) received 2 – 4 fractions of HDR-BT as monotherapy. The median follow-up time was 85 months. In total, 9.6% had a biochemical failure (BF) and severe toxicities were uncommon. The treatment was found to be effective and safe.

In paper II, 355 patients (83% classified as high- or very high risk) received EBRT (3 Gy x 14) + a single fraction of HDR-BT (14.5 Gy). The median follow-up time was 56 months. The estimated five-year failure free survival was 79 % for the whole cohort. Our results suggest that this treatment appears to be feasible in terms of efficacy.

In paper III, 34 patients who received EBRT + HDR-BT were randomized to either five or three fractions of EBRT per week. Intrafractional prostate movement was tracked in real-time using the Raypilot® system. The primary endpoint was patient-reported acute toxicity. We found no significant difference between the study groups. Target displacement was less than 2 mm during 97% of the time, supporting the use of small treatment margins.

In paper IV, 175 patients received two fractions of HDR-BT (14 Gy x 2) as monotherapy. The estimated five-year cumulative BF rate was 3% for low-risk patients and 9.6% for intermediate-risk patients. The proportion of severe urinary and bowel toxicities were low, indicating that this treatment approach is effective and safe.