Effect on prostate volume following neoadjuvant treatment with an androgen receptor inhibitor monotherapy versus castration plus an androgen receptor inhibitor in prostate cancer patients intended for curative radiation therapy: A randomised study

Abstract

Abstract. To avoid pubic arch interference, prostate cancer patients are treated with neoadjuvant androgen deprivation therapy (ADT) to achieve prostate volume (PV) reduction prior to radiation treatment. The aim of the present randomised study was to compare the effects on PV of two regimens of ADT, an androgen receptor inhibitor monotherapy vs. castration plus an androgen receptor inhibitor. Consecutive patients with non-metastatic prostate cancer were included in a randomised neoadjuvant study, comparing an androgen receptor inhibitor monotherapy vs. castration plus an androgen receptor inhibitor. PV was assessed prior to the start of endocrine neoadjuvant treatment and prior to the start of radiation therapy (RT). PV assessment was performed by transrectal ultrasound. A total of 110 patients were included. Final sample constituted 88 (80%) patients due to lack of PV information. Castration plus an androgen receptor inhibitor was more effective in PV reduction compared with an androgen receptor inhibitor alone (P<0.001). Planning target volume decreased in the combination arm. There was no significant difference in clinical or demographic or length of neoadjuvant hormonal treatment between the groups. Overall, a significantly larger PV reduction was achieved by castration plus androgen receptor inhibitor, as compared with androgen receptor inhibitor monotherapy. The PV reduction, however, appeared not to translate into better health associated quality of life during the subsequently given curative intended combined EBRT and HDR-brachytherapy. Potential differences between these two treatments regarding anti-tumor effects on micro metastatic disease and radiation potentiating effect remains to be addressed in future prospective trials.

Using a Further Planning MRI after Neoadjuvant Androgen Deprivation Therapy Significantly Reduces the Radiation Exposure of Organs at Risk in External Beam Radiotherapy of Prostate Cancer

“…The principal advantage of MRI-based radiotherapy treatment planning in prostate cancer has been known in the literature for years [ 22 , 23 , 24 , 25 , 26 ]. The reduction in prostate size under ADT measured in this study was within the range of other published studies [ 27 , 28 , 29 ]. The timing of starting ADT before or concurrently with radiotherapy is controversial for oncological efficacy [ 30 , 31 ].…”

First-line pembrolizumab plus androgen deprivation therapy for locally advanced microsatellite instability-high prostate cancer in a patient with Muir-Torre syndrome: A case report

“…The addition of androgen receptor inhibition has been shown to reduce prostate volume to a similar degree. A randomized study examining the resultant prostate volume of patients with localized prostate cancer treated with an average of 3 months of neoadjuvant bicalutamide monotherapy versus bicalutamide plus ADT prior to radiation showed that the mean volume reduction in the monotherapy arm was 17.5%, compared to 28% for the combined therapy arm (28). In a comparison of degarelix versus goserelin, with each administered over 3 months in the neoadjuvant setting, the mean percentage reduction in prostate volume was demonstrated to be -36.0% ± 14.5% versus -35.3% ± 16.7%, respectively (29).…”