Combined radiotherapy and hormone therapy in unfavorable intermediate risk prostate cancer

Abstract

Background. Currently, the group of intermediate risk prostate cancer (PC) includes 2 subgroups - favorable and unfavorable intermediate risk according to the National Comprehensive Cancer Network (NCCN) classification. The optimal scope of therapy is not defined for the unfavorable intermediate risk subgroup. In particular, the need for and duration of hormone therapy (HT) during combined radiotherapy (CRT) have not yet been determined.Aim. To perform a comparative analysis of the efficacy and toxicity of CRT in patients with unfavorable intermediate risk treated with and without HT.Materials and methods. Eighty-four (84) patients with unfavorable intermediate risk PC were treated with CRT at the clinic of the A.F. Tsyb Medical Radiological Research Center between May 2016 and December 2020. Patients were divided into two groups: external beam radiation therapy + brachytherapy (n = 40) and external beam radiation therapy + brachytherapy + HT (n = 44). Conformal external beam radiation therapy was delivered with conventional fractionation to a total dose of 44-46 Gy and the 192Ir high-dose rate brachytherapy was delivered with a single fraction of 15 Gy. Median duration of HT consisting of gonadotropin-releasing hormone agonist was 6 months. Median age was 65.2 years (range: 49-80 years). Median follow-up was 58.1 months (range: 18.6-83.7 months).Results. With a median follow-up of 4.8 years, progression-free survival was 95 % and 97.6 % in the external beam radiation therapy + brachytherapy group and external beam radiation therapy + brachytherapy + HT group, respectively (p = 0.578). The break between treatment stages of more than 28 days was associated with a statistically significant increase in the risk of PC recurrence (p = 0.007). Overall survival for the external beam radiation therapy + brachytherapy group versus external beam radiation therapy + brachytherapy + HT group was 97.5 and 93.2 % (p = 0.376), respectively.Late genitourinary toxicity was grade I in 8 (9.5 %) patients and grade II in 1 (1.2 %) patient. Urethral stricture developed in 3 (3.6 %) patients. Late gastrointestinal toxicity was grade I in 7 (8.3 %) patients and grade II in 1 (1.2 %) patient. There were no statistically significant differences in the incidence of late complications between groups with and without HT. There was a statistically significant (p = 0.049) effect of prostate volume on the incidence of late radiation proctitis.Conclusion. There were no statistically significant differences in progression-free survival and overall survival in patients with unfavorable intermediate risk PC who received external beam radiation therapy + brachytherapy with or without HT. The incidence and severity of adverse events were acceptable and allowed patients with PC to maintain high quality of life.