Objective Radium‐223 (Ra‐223) dichloride is the bone‐targeted radioligand therapy that prolongs overall survival (OS) in patients with bone‐metastatic castration‐resistant prostate cancer (CRPC). We aimed to evaluate the safety and effectiveness of this treatment in real‐world practice. Methods We included Japanese men treated with Ra‐223 for bone‐metastatic CRPC from 10 institutions, retrospectively. Primary endpoint was OS. Secondary endpoint was maximum decline of alkaline phosphatase (ALP), lactate dehydrogenase, and prostate‐specific antigen values, the rate of adverse events, and time to pathological fracture after Ra‐223 treatment. Exploratory endpoint was the associations between clinical parameters and OS. Results In total, 73 men with bone metastatic CRPC treated with Ra‐223 were enrolled. The median OS was 20.9 months. ALP levels decreased significantly from pre‐treatment (p = 0.03). Anemia occurred in three (4.1%) patients. Grade ≥ 3 non‐pathological fractures occurred in four (5.5%) men. Nine (12.3%) patients presented pathological fracture; 7/30 (23.3%) were in men without concomitant use of a bone‐modifying agent (BMA) while 2/43 (4.7%) were in patients with concomitant BMA (p = 0.03). The median OS in patients with ≥3 cycles treatment (27.2 months, p < 0.001) or hemoglobin ≥12 g/dl (27.2 months, p = 0.001) or absence of bone pain (36.3 months, p = 0.004) was significantly longer compared to those who with ≤2 cycles or hemoglobin<12 g/dl or presence of bone paint, respectively. Conclusions This study has shown the outcomes of Ra‐223 treatment in real‐world practice, where the number of treatment cycles, baseline anemia and bone pain may be useful to predict OS in Ra‐223 treatment.

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Introduction: This study aimed to highlight the comprehensive differences in adverse events between abiraterone and enzalutamide based on a big data data set. Methods:We downloaded adverse event data sets of abiraterone and enzalutamide from the Food and Drug Administration Adverse Event Reporting System database. We used the Medical Dictionary for Regulatory Activities to treat each adverse event as a preferred term and grouped it into the System Organ Class. Logistic regression analyses were performed to compare abiraterone and enzalutamide.Results: In total, we extracted 59,680 data sets. After exclusion by criteria, we included 26,015 reports on enzalutamide and 7,507 on abiraterone. Enzalutamide and abiraterone presented different toxicity profiles in most System Organ Classes. Overall, the reporting odds ratio indicated a higher incidence rate of serious adverse events for abiraterone than enzalutamide. Conclusions:In conclusion, our findings suggest that both drugs present a discrete and nonoverlapping toxicity profile that varies by System Organ Class and patient age. This data set confirms, for the most part, what has been reported in clinical trials as well as true real-world reports.

Several studies have identified various targetable genomic alterations in prostate cancer, which accumulate during carcinogenesis and cancer progression. Genomic alterations in genes involved in DNA damage repair by homologous recombination repair may predict increased sensitivity to poly-ADP ribose polymerase (PARP) inhibitors. The Phase 3 PROfound trial has shown that treatment with the PARP inhibitor olaparib was associated with an improved radiographic progression-free survival and overall survival among patients with homologous recombination repair-deficient metastatic castration-resistant prostate cancer (mCRPC) after the treatment with androgen receptor targeting therapy, especially in men with BRCA1 or BRCA2 mutation. In Japan, olaparib was approved in December 2020 for the treatment of mCRPC with BRCA1 or BRCA2 mutation. In addition, genetic tests to detect BRCA1 or BRCA2 mutation to select patients who are likely to benefit from olaparib were also approved. This review summarizes the status of olaparib treatment for mCRPC, focusing on the situation in Japan.

Objectives: Semen comprises prostatic fluid and seminal vesicle fluid, and seminal vesicle fluid contains various factors such as prostaglandin E2 (PGE2), zinc, and testosterone, which play important roles in sperm motility. It is not known whether these factors affect erectile function. In this study, we investigated factors in seminal vesicle fluid that may affect erectile function. Methods: After receiving institutional review board approval, we collected seminal vesicle fluid samples from 134 Japanese patients with localized prostate cancer who underwent robot-assisted radical prostatectomy. We examined the relationship between the results of the Sexual Health Inventory for Men (SHIM), erection hardness score, an original questionnaire on the presence or absence of sexual desire, and concentrations of several factors in seminal vesicle fluid (testosterone, PGE2, transforming growth factor b1, and 8-hydroxy-2-deoxyguanosine), as well as the serum testosterone level. Results: Median participant age was 67 (range 51-77) years. Median concentrations were as follows: seminal vesicle testosterone 1.85 (range 0.17-4.32) ng/ml and serum testosterone 4.60 (range 1.75-10.82) ng/ml. When the SHIM score was divided into two groups, seminal vesicle testosterone concentration was significantly increased (p = 0.002) in participants with a SHIM score ≥17, and no significant difference was observed in serum testosterone levels (p = 0.661). Multivariate analysis revealed that seminal vesicle testosterone was significantly correlated with the SHIM score (≥17 vs. <17; odds ratio 2.137, 95% confidence interval 1.148-3.978, p = 0.016). Conclusions: Testosterone levels in seminal vesicle fluid can reflect erectile function in patients with prostate cancer, suggesting that seminal vesicle testosterone is very important for male erectile function.

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