High-dose-rate brachytherapy as monotherapy for prostate cancer: 5-year results

Objective: to evaluate clinical outcomes in patients with prostate cancer treated with high-dose-rate (HDR) brachytherapy (BT) as monotherapy.

Materials and methods. From January 2015 to December 2017, 97 men with localized prostate cancer underwent HDR-BT as monotherapy, with a temporary implant on a MicroSelectron HDR device. The dose prescription was: 30 Gy in 2 fractions with an interval of 2 weeks. The overall and biochemical survival rate was assessed. The assessment of genitourinary and gastrointestinal toxicity was also carried out. The quality of life associated with urination before treatment and in dynamics during 5 years of observation, as well as the frequency and degree of development of erectile dysfunctionand its dynamics during the entire observation period were analyzed.

Results. The median age was 65.2 (44 to 80) years. Overall, 29 patients had low risk prostate cancer, 63 patients had moderate risk, and 5 patients – high risk. The follow-up period was five years (range, 18 to 72 months). The median follow-up was 54.3 (95 % confidence interval 52.3–59) months. Overall survival and survival without biochemical recurrence were 96 and 99 %, respectively. Toxicity was assessed according to the RTOG/EORTC (Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer) scale for each event. Late genitourinary toxic reactions of grade 1 and 2 were noted in 23.9 and 6.3 %, respectively. Late gastrointestinal grade 2 toxicity was not observed. Genitourinary and gastrointestinal toxic reactions of grade 3 were not observed. The quality of life associated with urination after treatment was comparable to the level of quality of life at the time of inclusion of patients in the treatment protocol. Erectile dysfunction developed to a greater extentin the first 1–2 years after HDR-BT with a subsequenttendency to recovery.

Conclusion. HDR-BT as monotherapy is a safe and highly effective treatment for localized prostate cancer. The fractionation mode in the form of 30 Gy for 2 fractions of 15 Gy with an interval of 2 weeks with or without dose modulation in the area of the tumor focus using a gel has a low toxicity profile from the side of critical organs.

1. Yamazaki H., Masui K., Suzuki G. et al. High-dose-rate brachytherapy monotherapy versus low-dose-rate brachytherapy with or without external beam radiotherapy for clinically localized prostate cancer. Radiother Oncol 2019;132:162–70. DOI: 10.1016/j.radonc.2018.10.020.

2. Crook J.M., Gomez-Iturriaga A., Wallace K. et al. Comparison of healthrelated quality of life 5 years after SPIRIT: Surgical Prostatectomy Versus Interstitial Radiation Intervention Trial. J Clin Oncol 2011;29(4):362–8. DOI: 10.1200/JCO.2010.31.7305.

3. Strouthos I., Karagiannis E., Zamboglou N., Ferentinos K. High-doserate brachytherapy for prostate cancer: Rationale, current applications, and clinical outcome. Cancer Rep (Hoboken) 2021;5(1):e1450. DOI: 10.1002/cnr2.1450.

4. Johansson B., Olsén J.S., Karlsson L. et al. High-dose-rate brachytherapy as monotherapy for low- and intermediate-risk prostate cancer: long-term experience of Swedish single-center. J Contemp Brachytherapy 2021;13(3):245–53. DOI: 10.5114/jcb.2021.105846.

5. Soatti C.P., Delishaj D., D’Amico R. et al. High-dose-rate brachytherapy as monotherapy for localized prostate cancer using three different doses – 14 years of singlecentre experience. J Contemp Brachytherapy 2020;12(6):533–9. DOI: 10.5114/jcb.2020.101685.

6. Morton G., McGuffin M., Chung H.T. et al. Prostate high dose-rate brachytherapy as monotherapy for low and intermediate risk prostate cancer: Efficacy results from a randomized phase II clinical trial of one fraction of 19 Gy or two fractions of 13.5 Gy. Radiother Oncol 2020;146:90–6. DOI: 10.1016/j.radonc.2020.02.009.

7. Zaorsky N.G., Harrison A.S., Trabulsi E.J. et al. Evolution of advanced technologies in prostate cancer radiotherapy. Nat Rev Urol 2013;10(10):565–79. DOI: 10.1038/nrurol.2013.185.

8. Yoshioka Y., Suzuki O., Isohashi F. et al. High-dose-rate brachytherapy as monotherapy for intermediate- and high-risk prostate cancer: clinical results for a median 8-year follow-up. Int J Radiat Oncol Biol Phys 2016;94(4):675–82. DOI: 10.1016/j.ijrobp.2015.05.044.

9. Behmueller M., Tselis N., Zamboglou N. et al. High-dose-rate brachytherapy as monotherapy for low- and intermediaterisk prostate cancer. Oncological outcomes after a median 15-year follow-up. Front Oncol 2021;11:770959. DOI: 10.3389/fonc.2021.770959.

10. Vanneste B.G., van Limbergen E.J., van Lin E.N. et al. Prostate cancer radiation therapy: what do clinicians have to know? Biomed Res Int 2016;2016: 6829875. DOI: 10.1155/2016/6829875.

11. Vogelius I.R., Bentzen S.M. Metaanalysis of the alpha/beta ratio for prostate cancer in the presence of an overall time factor: bad news, good news, or no news? Int J Radiat Oncol Biol Phys 2013;85(1):89–94. DOI: 10.1016/j.ijrobp.2012.03.004.

12. King C.R. LDR vs. HDR brachytherapy for localized prostate cancer: the view from radiobiological models. Brachytherapy 2002;1(4):219–26. DOI: 10.1016/S1538-4721(02)00101-0.

13. Martell K., Kollmeier M.A. Complications and side effects of high-dose-rate prostate brachytherapy. Brachytherapy 2021;20(5):966–75. DOI: 10.1016/j.brachy.2020.10.007.