Risk of prostate cancer death after radical radiotherapy with neoadjuvant and adjuvant therapy with bicalutamide or gonadotropin-releasing hormone agonists.

BACKGROUND: Oncological outcome after radical radiotherapy (RRT) combined with neoadjuvant and adjuvant androgen suppression therapy (AST) may differ according to type of AST. The aim of this nationwide register-based study was to investigate risk of prostate cancer (Pca) death after different neoadjuvant and adjuvant ASTs; (i) bicalutamide, (ii) gonadotropin-releasing hormone agonists (GnRH) or (iii) combined bicalutamide and GnRH (CAB), together with RRT. MATERIALS AND METHODS: Data for 6882 men diagnosed with high-risk Pca between 2007 and 2020 and treated with primary RRT was retrieved from Prostate Cancer data Base Sweden (PCBaSe) 5.0. Time to Pca death according to type of neoadjuvant and adjuvant AST was assessed by use of Kaplan-Meier plots and Cox proportional hazard models adjusted for putative confounders. RESULTS: Data were stratified by RRT type since the effect of AST in risk of Pca death differed according to type of RRT. Compared with the reference RRT combined with neoadjuvant CAB/adjuvant GnRH, risk of Pca death for men treated with CAB/bicalutamide and conventionally fractionated external beam radiotherapy (CF-EBRT) was hazard ratio (HR) 0.73 (95% CI: 0.50-1.04), hypofractionated EBRT (HF-EBRT), HR 1.35 (95% CI: 0.65-2.81) and EBRT with high dose rate brachytherapy (EBRT-HDRBT), HR 0.85 (95% CI: 0.37-1.95). Risk of Pca death for men treated with bicalutamide/bicalutamide and: (i) CF-EBRT was HR 2.35 (95% CI: 1.42-3.90), (ii) HF-EBRT, HR 0.70 (95% CI: 0.26-1.85), (iii) HF-EBRT, HR 4.07 (95% CI: 1.88-8.77) vs the reference. CONCLUSION: In this observational study, risk of Pca death between men receiving different combinations of AST varied according to RRT type. No difference was found in risk of Pca death for men treated with bicalutamide or GnRH as adjuvant therapy to RRT following neoadjuvant CAB. Risk of Pca death was increased for men with monotherapy neo-/adjuvant bicalutamide in combination with CF-EBRT or EBRT-HDRBT.

Time to castration-resistant prostate cancer and prostate cancer death according to PSA response in men with non-metastatic prostate cancer treated with gonadotropin releasing hormone agonists.

Objectives: To predict castration-resistant prostate cancer (CRPC) and prostate cancer (Pca) death by use of clinical variables at Pca diagnosis and PSA levels after start of gonadotropin-releasing hormone agonists (GnRH) in men with non-metastatic castration sensitive prostate cancer (nmCSPC).Materials and Methods: PSA values for 1603 men with nmCSPC in the National Prostate Cancer Register of Sweden who received GnRH as primary treatment were retrieved from Uppsala-Örebro PSA Cohort and Stockholm PSA and Biopsy Register. All men had measured PSA before (pre-GnRH PSA) and 3-6 months after (post-GnRH PSA) date of start of GnRH. Unadjusted and adjusted Cox models were used to predict CRPC by PSA levels. PSA levels and ISUP grade were used to construct a risk score to stratify men by tertiles according to risk of CRPC and Pca death.Results: 788 (49%) men reached CRPC and 456 (28%) died of Pca during follow-up. Post-GnRH PSA predicted CRPC regardless of pre-GnRH PSA. CRPC risk increased with higher post-GnRH PSA, HR 4.7 (95% CI: 3.4-6.7) for PSA > 16 ng/mL vs 0-0.25 ng/mL and with ISUP grade, HR 3.7 (95%: 2.5-5.4) for ISUP 5 vs ISUP 1. Risk of Pca death in men above top vs bellow bottom tertile of post-GnRH PSA and ISUP grade was HR 4.1 (95% CI: 3.0-5.5).Conclusion: A risk score based on post-GnRH PSA and ISUP grade could be used for early identification of a target group for future clinical trials on additional therapy to GnRH.