Aims: The treatment of intermediate- to high-risk prostate cancer with radical radiotherapy is usually in combination with neoadjuvant androgen deprivation therapy. The aim of the present trial was to investigate whether degarelix achieves comparable efficacy with that of goserelin plus bicalutamide as neoadjuvant therapy before radiotherapy.

Materials and methods: The study was a randomised, parallel-arm, active-controlled, open-label trial in 244 men with a UICC prostate cancer TNM category T2b-T4, N0, M0, Gleason score ≥7, or prostate-specific antigen ≥10 ng/ml and a total prostate volume >30 ml, who were scheduled to undergo radical radiotherapy and in whom neoadjuvant androgen deprivation therapy was indicated. Eligible patients received treatment with either monthly degarelix (240/80 mg) or goserelin (3.6 mg) for 12 weeks, the latter patients also receiving bicalutamide (50 mg) for 17 days initially. The primary efficacy measure was the mean percentage reduction in total prostate volume from baseline at week 12 measured by transrectal ultrasound. The severity and relief of lower urinary tract symptoms were assessed by the International Prostate Symptom Score questionnaire. Quality of life was assessed by the eighth question of the International Prostate Symptom Score. About 50% of the patients had moderate to severe lower urinary tract symptoms at baseline.

Results: The total prostate volume decreased significantly from baseline to week 12 in both treatment groups, reaching -36.0 ± 14.5% in degarelix-treated patients and -35.3 ± 16.7% in goserelin-treated patients (adjusted difference: -0.3%; 95% confidence interval: -4.74; 4.14%). At the end of the therapy, more degarelix- than goserelin-treated patients reported International Prostate Symptom Score decreases of ≥3 points (37% versus 27%, P = 0.21). In addition, in patients with a baseline International Prostate Symptom Score of ≥13, the magnitude of the decrease was larger in degarelix- (n = 53) versus goserelin-treated patients (n = 17) (6.04 versus 3.41, P = 0.06).

Conclusions: The efficacy of degarelix in terms of prostate shrinkage is non-inferior to that of goserelin plus bicalutamide. The added benefits of degarelix in terms of more pronounced lower urinary tract symptom relief in symptomatic patients could be the reflection of differences in the direct effects on extra-pituitary receptors in the lower urinary tract [Clinicaltrials.gov ID: NCT00833248].