Long-term outcomes in 1121 Australian prostate cancer patients treated with definitive radiotherapy

Comparison of EBRT and I-125 seed brachytherapy concerning outcome in intermediate-risk prostate cancer

PURPOSE

This study's objective was the comparison of external beam radiotherapy (EBRT) and I‑125 seed brachytherapy regarding clinical outcome and development of side effects.

PATIENTS AND METHODS

In all, 462 localized intermediate-risk prostate cancer patients treated between 2000 and 2019 at our department using either I‑125 seed brachytherapy or EBRT with a dose of 74 or 78 Gy were included: 297 patients were treated with EBRT and 165 with seeds. Biochemical no evidence of disease (bNED) rates according to Phoenix definition as well as late gastrointestinal and urogenital side effects (EORTC/RTOG) were assessed.

RESULTS

Patients were followed up yearly with a median follow-up of 54 (3-192) months. Observed bNED rates for 74 Gy, 78 Gy and seeds were 87, 92, and 88% after 5 years and 71, 85, and 76% after 9 years, respectively. No significant differences were found comparing seeds with 74 Gy (p = 0.81) and 78 Gy (p = 0.19), as well as between 74 and 78 Gy (p = 0.32). Concerning gastrointestinal side effects, EBRT showed significantly higher rates of RTOG grade ≥ 2 toxicity compared to seeds, but at no point of the follow-up more than 10% of all patients. However, genitourinary side effects were significantly more prevalent in patients treated with seeds, with 33% RTOG grade ≥ 2 toxicity 12 months after treatment. Nevertheless, both types of side effects decreased over time.

CONCLUSION

Favorable intermediate-risk prostate cancer patients can be treated either by external beam radiotherapy (74/78 Gy) or permanent interstitial seed brachytherapy.

Treatment of low-risk prostate cancer: a retrospective study with 477 patients comparing external beam radiotherapy and I-125 seeds brachytherapy in terms of biochemical control and late side effects

PURPOSE

The goal of our study was comparison of external beam radiotherapy (EBRT) and I‑125 seeds brachytherapy in terms of biochemical control and development of late gastrointestinal and genitourinary side effects.

PATIENTS AND METHODS

477 low-risk prostate cancer patients treated between 2000 and 2019 at our department using either I‑125 seeds brachytherapy or EBRT with a dose of 74 or 78 Gy were reviewed for our analysis. 213 patients were treated with EBRT and 264 with seeds.

RESULTS

Patients were followed up yearly with a median follow-up of 70 (3-192) months. The biochemical no evidence of disease (bNED) rates after 5 years were 95% for both EBRT and seeds, and after 10 years 87% for EBRT and 94% for seeds using the Phoenix criteria, although no significant difference was observed. Concerning gastrointestinal side effects, EBRT showed significantly higher rates of RTOG grade ≥2 toxicity compared to seeds, but at no point in follow-up more than 15% of all patients. On the other hand, genitourinary side effects were significantly more prevalent in patients treated with seeds, with 40% RTOG grade ≥2 toxicity 12 months after treatment. Nevertheless, both types of side effects decreased over time.

CONCLUSION

Both EBRT and seeds provide excellent biochemical control with bNED rates after 10 years of about 90%. In terms of side effects, patients treated with seeds show higher grades of genitourinary side effects, while patients treated with EBRT show higher grades of gastrointestinal side effects.