Outcomes of active surveillance for Japanese patients with prostate cancer (PRIAS-JAPAN).

OBJECTIVE: To report the outcomes of repeat biopsies, metastasis and survival in the Prostate Cancer Research International: Active Surveillance (PRIAS)-JAPAN study, a prospective observational study for Japanese patients, initiated in 2010. PATIENTS AND METHODS: At the beginning, inclusion criteria were initially low-risk patients, prostate-specific antigen (PSA) density (PSAD) <0.2, and ≤2 positive biopsy cores. As from 2014, GS3+4 has also been allowed for patients aged 70 years and over. Since January 2021, the age limit for Gleason score (GS) 3 + 4 cases was removed, and eligibility criteria were expanded to PSA ≤20 ng/mL, PSAD <0.25 nd/mL/cc, unlimited number of positive GS 3 + 3 cores, and positive results for fewer than half of the total number of cores for GS 3 + 4 cases if magnetic resonance imaging fusion biopsy was performed at study enrolment or subsequent follow-up. For patients eligible for active surveillance, PSA tests were performed every 3 months, rectal examination every 6 months, and biopsies at 1, 4, 7 and 10 years, followed by every 5 years thereafter. Patients with confirmed pathological reclassification were recommended for secondary treatments. RESULTS: As of February 2024, 1302 patients were enrolled in AS; 1274 (98%) met the eligibility criteria. The median (interquartile range) age, PSA level, PSAD, and number of positive cores were 69 (64-73) years, 5.3 (4.5-6.6) ng/mL, 0.15 (0.12-0.17) ng/mL, and 1 (1-2), respectively. The clinical stage was T1c in 1089 patients (86%) and T2 in 185 (15%). The rates of acceptance by patients for the first, second, third and fourth re-biopsies were 83%, 64%, 41% and 22%, respectively. The pathological reclassification rates for the first, second, third and fourth re-biopsies were 29%, 30%, 35% and 25%, respectively. The 1-, 5- and 10-year persistence rates were 77%, 45% and 23%, respectively. Six patients developed metastasis, and one patient died from prostate cancer. CONCLUSION: Pathological reclassification was observed in approximately 30% of the patients during biopsy; however, biopsy acceptance rates decreased over time. Although metastasis occurred in six patients, only one death from prostate cancer was recorded.

Validation study on the 2 mm diameter cutoff in lymph node-positive cases following radical prostatectomy in accordance with the AJCC/UICC TNM 8th edition: Real-world data analysis from a Japanese cohort.

OBJECTIVES: The American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) 8th edition has proposed micrometastasis as a lymph node metastasis (LN+) of diameter ≤2 mm in prostate cancer. However, supporting evidence has not described. We evaluated LN+ patients' survival after radical prostatectomy (RP) based on the LN maximum tumor diameter (MTD). METHODS: Data from 561 LN+ patients after RP and pelvic LN dissection (PLND) treated between 2006 and 2019 at 33 institutions were retrospectively investigated. Patients were stratified by a LN+ MTD cutoff of 2 mm. Outcomes included castration resistance-free survival (CRFS), metastasis-free survival (MFS), cancer-specific survival (CSS), and overall survival (OS). RESULTS: In total, 282 patients were divided into two groups (LN+ MTD >2 mm [n = 206] and ≤2 mm [n = 76]). Patients of LN+ status >2 mm exhibited significantly decreased CRFS and MFS, and poorer CSS and OS. No patients developed CRPC in the LN+ status ≤2 mm group when the PLND number was ≥14. Multivariate analysis showed the number of LN removed, RP Gleason pattern 5, and MTD in LN+ significantly predicted CRFS. CONCLUSIONS: Patients of LN+ status ≤2 mm showed better prognoses after RP. In all the patients in the ≤2-mm group, the progression to CRPC could be prevented with appropriate interventions, particularly when PLND is performed accurately. Our findings support the utility of the pN substaging proposed by the AJCC/UICC 8th edition; this will facilitate precision medicine for patients with advanced prostate cancer.

The effect of human leukocyte antigen genotype on survival in advanced prostate cancer treated with primary androgen deprivation therapy: the KYUCOG-1401-A study.

BACKGROUND: Immune editing, in which human leukocyte antigens (HLA) have critical roles, has been suggested to shape the landscape of human cancer. This study prospectively investigated whether HLA gene zygosity is associated with the prognosis of primary androgen deprivation therapy in advanced prostate cancer. METHODS: KYUCOG-1401-A was conducted in conjunction with a prospective clinical trial (KYUCOG-1401). Among the patients enrolled in KYUCOG-1401 and treated with primary androgen deprivation therapy, only Japanese patients were included. HLA genotypes of HLA-A, B, C, DRB1, DQB1, and DPB1 were determined. The effect of divergence of HLA genotypes on time to progression, prostate cancer-specific survival, and overall survival was evaluated. RESULTS: Among 127 patients, homozygosity for HLA-DRB1 (HR, 95% CI; 4.05, 1.54-10.7, P = 0.0047) and HLA-DQB1 (HR, 95% CI; 3.75, 1.47-9.58, P = 0.0058) was associated with an increased risk of prostate cancer-specific mortality. Patients with higher HLA evolutionary divergence scores at HLA-DQB1 (HR, 95% CI; 0.90, 0.82-0.97, P = 0.0093) had lower risks of prostate cancer-specific mortality. Androgen-responsive gene sets were upregulated in CD4low and CD8low tumors in the prostate cancer cohort, but not in the bladder and kidney cancer cohorts. CONCLUSIONS: This study suggested that the diversity of HLA-II loci including HLA-DRB1 and HLA-DQB1 plays an important role in advanced prostate cancer survival, contributing to improved risk stratification in advanced prostate cancer. Moreover, it was shown that CD4+ T cells play an important role in androgen deprivation therapy, suggesting that immunotherapy targeting CD4+ T cells is promising for prostate cancer.

Prognostication in Lymph Node-Positive Prostate Cancer with No PSA Persistence After Radical Prostatectomy.

BACKGROUND: This study aimed to create a prognostic model to predict disease recurrence among patients with lymph node involvement but no prostate-specific antigen (PSA) persistence and to explore its clinical utility. METHODS: The study analyzed patients with lymph node involvement after pelvic lymph node dissection with radical prostatectomy in whom no PSA persistence was observed between 2006 and 2019 at 33 institutions. Prognostic factors for recurrence-free survival (RFS) were analyzed by the Cox proportional hazards model. RESULTS: Among 231 patients, 127 experienced disease recurrence. The factors prognostic for RFS were PSA level at diagnosis (≥ 20 vs. < 20 ng/mL: hazard ratio [HR], 1.66; 95% confidence interval [CI], 1.09-2.52; P = 0.017), International Society of Urological Pathology grade group at radical prostatectomy (RP) specimen (group ≥ 4 vs. ≤ 3: HR, 1.63; 95% CI 1.12-2.37; P = 0.010), pathologic T-stage (pT3b/4 vs. pT2/3a: HR, 1.70; 95% CI 1.20-2.42; P = 0.0031), and surgical margin status (positive vs. negative: HR, 1.60; 95% CI 1.13-2.28; P = 0.0086). The prognostic model using four parameters were associated with RFS and metastasis-free survival. CONCLUSION: The prognostic model in combination with postoperative PSA value and number of lymph nodes is clinically useful for discussing treatment choice with patients.

Metastatic castration resistant prostate cancer patients' experience with Radium-223 treatment in Japan.

Aim: We aimed to determine Japanese metastatic castration resistant prostate cancer (CRPC) patients' Ra-223 treatment experience. Patients & methods: Patients answered the Cancer Therapy Satisfaction Questionnaire (CTSQ domains: Satisfaction with Therapy [SWT], Expectations of Therapy [ET], Feelings about Side Effects [FSE]), the Memorial Anxiety Scale for Prostate Cancer (MAX-PC) and the FACT-Bone Pain (FACT-BP) Questionnaire at baseline, during (vists 3 and 5) and after treatment (end of observation; EOO). Results: Data from 72 patients were included. Baseline median CTSQ scores SWT: 66.1 (IQR19.7), ET: 75.0 (IQR45), and FSE 68.8 (IQR 34.4) were unchanged during vists 3 and 5, but the SWT (-3.57 [IQR17.9]) and ET (-5.0 [IQR30]) decreased while FSE was unchanged (0.0 [IQR31.25]) at EOO. The median MAX-PC (18.0 [IQR 49]) score was unchanged (0.0, IQR 6) while the median FACT BP (54.0 [IQR13]) score decreased by -1.0 (IQR 8) at EOO. Conclusion: Japanese metastatic castration resistant prostate cancer patients' experience is stable during Ra-223 treatment.

What is this study about? We wanted to know the treatment experience with Radium-223 (Ra-223) among Japanese prostate cancer patients. Ra-223 is a radioactive molecule used for the treatment of metastatic castration resistant prostate cancer. We asked patients to answer different questionnaires on treatment satisfaction, anxiety and quality of life before, during, and after treatment with Ra-223. What were the results? Based on the patients' answers to our questionnaires, treatment satisfaction, anxiety and quality of life remain stable while the patients undergo treatment with Ra-223, but in some aspects may decline after treatment. What do the results mean? The results mean that patients' experience during Ra-223 treatment is stable but patients should share any concerns they have about their treatment with their doctors.

GnRH antagonist monotherapy versus a GnRH agonist plus bicalutamide for advanced hormone-sensitive prostate cancer; KYUCOG-1401.

OBJECTIVES: To compare the effectiveness and safety of gonadotropin-releasing hormone (GnRH) antagonist monotherapy to combined androgen blockade (CAB) with a GnRH agonist and bicalutamide in patients with advanced hormone-sensitive prostate cancer (HSPC). METHODS: The study was conducted as KYUCOG-1401 trial (UMIN000014243) and enrolled 200 patients who were randomly assigned to either group A (GnRH antagonist monotherapy followed by the addition of bicalutamide) or group B (CAB by a GnRH agonist and bicalutamide). The primary endpoint was PSA progression-free survival. The secondary endpoints were the time to CAB treatment failure, radiographic progression-free survival, overall survival, changes in serum parameters, including PSA, hormones, and bone and lipid metabolic markers, and adverse events. RESULTS: PSA progression-free survival was significantly longer in group B (hazard ratio [HR], 95% confidence interval [CI]; 1.40, 1.01-1.95, p = 0.041). The time to CAB treatment failure was slightly longer in group A (HR, 95% CI; 0.80, 0.59-1.08, p = 0.146). No significant differences were observed in radiographic progression-free survival or overall survival. The percentage of patients with serum testosterone that did not reach the castration level was higher at 60 weeks (p = 0.046) in group A. No significant differences were noted in the serum levels of bone metabolic or lipid markers between the two groups. An injection site reaction was more frequent in group A. CONCLUSIONS: The present results support the potential of CAB using a GnRH agonist and bicalutamide as a more effective treatment for advanced HSPC than GnRH antagonist monotherapy.

Efficacy and safety of axitinib for metastatic renal cell carcinoma: Real-world data on patients with renal impairment.

OBJECTIVES: Limited information is currently available on the efficacy and safety of axitinib for metastatic renal cell carcinoma (mRCC) patients with renal impairment. Therefore, the present study investigated the efficacy and toxicity of axitinib in patients with chronic kidney disease. METHODS: Post-hoc analyses were performed on a Japanese multicenter cohort study of 477 mRCC patients who received axitinib followed by 1 or 2 regimens of systemic antiangiogenic therapy between January 2012 and December 2016. Differences in clinical characteristics and the efficacy and safety of axitinib were assessed based on pretreatment renal function. RESULTS: Patients were categorized into the following 5 renal function groups according to baseline renal function: estimated glomerular filtration rate (eGFR) ≥60 ml/min (n = 133), 45 ml/min ≤eGFR <60 ml/min (n = 153), 30 ml/min ≤eGFR< 45 ml/min (n = 130), eGFR <30 ml/min (n = 45), and dialysis (n = 16). Median progression-free survival (PFS) (95% confidence interval [CI]) in the 5 groups was 11 (8-16), 14 (11-19), 14 (10-19), 12 (8-24), and 6 (3-NR) months, respectively (p = 0.781). After adjustments for treatment-related confounders, the renal function group was not a significant prognostic factor for PFS. Objective response rates in the 5 groups were 22%, 23%, 23%, 18%, 20%, and 38%, respectively (p = 0.468). Regarding adverse events of all grades, hypertension (p = 0.0006) and renal and urinary disorders (p < 0.0001) were more frequently observed in the eGFR <30 ml/min group than in the other groups. CONCLUSIONS: Since renal function at the initiation of treatment with axitinib does not adversely affect the efficacy of VEGF-TKI therapy, clinicians do not need to avoid its administration to mRCC patients with impaired renal function in consideration of the risk of progression to end-stage renal disease.

Bone-modifying agents are protective for symptomatic skeletal events in Radium-223 treatment.

INTRODUCTION: Radium-223 (Ra-223) dichloride therapy increases overall survival and delays time to the first symptomatic skeletal event (SSE) in patients with castration-resistant prostate cancer (CRPC) and bone metastases. Bone-modifying agents (BMA) reduce SSE in patients with bone metastasis, but there is little information on their use with Ra-223. This study aimed to investigate the effect of BMA on SSE in patients with bone metastatic CRPC treated with Ra-223 in real-world practice. METHODS: We included 73 patients treated with Ra-223 from 10 institutions in Japan. Time to the first SSE was estimated using the Kaplan-Meier method and compared between groups using the log-rank test. We used univariate analysis to ascertain the association between variables and SSE. RESULTS: During a median follow-up of 12.7 months (interquartile range, 7-21.7), 12 (16.4%) patients presented SSE. Age and BMA use were different between men with and without SSE. The 1-year SSE-free survival rate from Ra-223 treatment initiation was 82.4% (95% CI, 69.4%-90.2%). BMA use was associated with favorable SSE-free survival (hazard risk, 0.23; 95% confidence interval, 0.061-0.85; p = 0.027). Two (4.7%) and seven (23.3%) patients presented symptomatic pathological bone fracture in groups with and without BMA use, respectively (p = 0.017). CONCLUSION: This study stresses the importance of BMA use in patients with CRPC and bone metastases in Ra-223 treatment.

Genome-wide association studies in advanced prostate cancer: KYUCOG-1401-A study.

Androgen-deprivation therapy (ADT) has been widely used for the treatment of advanced prostate cancer. However, prognosis and adverse events (AEs) vary among patients. This study aimed to identify genetic markers able to predict the outcome of ADT. Japanese patients treated with primary ADT for advanced prostate cancer in the KYUCOG-1401 trial were enrolled as a development set. A distinct population of advanced prostate cancer cases treated with ADT was included as a validation set. Single-nucleotide polymorphisms (SNPs) associated with radiographic progression-free survival (rPFS) at 1 year and AEs including de novo diabetes mellitus (DM), arthralgia, and de novo dyslipidemia were identified in the development set by a genome-wide association study (GWAS). The SNPs associated with rPFS in the development study were then genotyped in the validation set. GWAS followed by validation identified SNPs (rs76237622 in PRR27 and rs117573572 in MTAP) that were associated with overall survival (OS) in ADT. A genetic prognostic model using these SNPs showed excellent predictive efficacy for PFS and OS in ADT. In addition, GWAS showed that several SNPs were associated with de novo DM, arthralgia, and de novo dyslipidemia in ADT. This study identified novel multiple SNPs that correlated with outcomes in ADT. Future studies on correlations affecting the therapeutic efficacy of ADT-based combination therapies would make a valuable contribution to the development of personalized medicine.

Effectiveness and safety of radium-223 dichloride in patients with castration-resistant prostate cancer and bone metastases in real-world practice: A multi-institutional study.

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.

Discontinuation of pembrolizumab for advanced urothelial carcinoma without disease progression: Nationwide cohort study.

Pembrolizumab, an anti-programmed death 1 monoclonal antibody, has revolutionized the treatment of metastatic urothelial carcinoma. However, the optimal treatment duration for treatment responders has not been established. To address this, we retrospectively assess the treatment outcomes and duration of pembrolizumab for patients whose best response was complete response (CR) or partial response (PR) in a Japanese nationwide cohort of platinum-refractory metastatic urothelial carcinoma. Of 203 patients whose best response was CR or PR, 83 patients discontinued pembrolizumab before progression. The median pembrolizumab treatment duration was 6.9 months. The 2-year relapse-free survival (RFS), treatment-free survival, and OS rates after discontinuation were 49.0%, 57.4%, and 74.5%, respectively. CR, higher hemoglobin levels, and a better Eastern Cooperative Oncology Group performance status at the time of discontinuation were associated with significantly better RFS. Pembrolizumab was re-administered to 12 patients. Pembrolizumab re-challenge resulted in CR, PR, stable disease, and progressive disease in six, three, two, and one patient, respectively. Propensity score-matched landmark analysis revealed no significant OS difference between patients who continued or discontinued pembrolizumab at 6, 12, and 18 months (p = 0.91, 0.99, and 0.25, respectively). Our findings demonstrated that patients with objective responses had favorable survival outcomes and suggested that pembrolizumab could be discontinued safely in this population. This study should drive further efforts to optimize the treatment duration for pembrolizumab responders.

Health-related quality of life with enzalutamide versus flutamide in castration-resistant prostate cancer from the AFTERCAB study.

BACKGROUND: Patient-reported outcome (PRO) measures can provide valuable information in evaluating patients' health-related quality of life (HRQoL). Post hoc analysis of the AFTERCAB study was conducted to evaluate the HRQoL benefit of enzalutamide plus androgen deprivation therapy (ADT) compared to flutamide plus ADT for the treatment of patients with castration-resistant prostate cancer (CRPC) in Japan. METHODS: The open-label AFTERCAB study was conducted from November 2016 to March 2020 in Japanese men aged ≥ 20 years with asymptomatic or mildly symptomatic CRPC. Patients received enzalutamide plus ADT or flutamide plus ADT, respectively, as first-line alternative androgen therapy (AAT). HRQoL was analyzed through the Functional Assessment of Cancer Therapy-Prostate, EuroQoL 5-Dimension 5-Level instruments, Brief Pain Inventory-Short Form, and Brief Fatigue Inventory. The longitudinal changes in HRQoL, HRQoL deterioration based on minimally important difference (MID), and time to HRQoL deterioration were evaluated for first-line AAT. RESULTS: Overall, HRQoL between the enzalutamide and flutamide groups was similar during first-line treatment. No statistically significant HRQoL difference in change from baseline to week 61 (least square mean difference; p value) was observed. Furthermore, proportions of pain progression, symptom worsening, and HRQoL deterioration based on MID, were not significantly different between groups. CONCLUSIONS: The results were similar in all subscales of each PRO, demonstrating similar HRQoL deterioration based on MID criteria between the enzalutamide and flutamide groups.

Comparison of the medical costs between active surveillance and other treatments for early prostate cancer in Japan using data from the PRIAS-JAPAN study.

OBJECTIVES: To compare the medical costs of active surveillance with those of robot-assisted laparoscopic prostatectomy, brachytherapy, intensity-modulated radiation therapy, and hormone therapy for low-risk prostate cancer. METHODS: The costs of protocol biopsies performed in the first year of surveillance (between January 2010 and June 2020) and those of brachytherapy and radiation therapy performed between May 2019 and June 2020 at the Kagawa University Hospital were analyzed. Hormone therapy costs were assumed to be the costs of luteinizing hormone-releasing hormone analogs for over 5 years. Active surveillance-eligible patients were defined based on the following: age <74 years, ≤T2, Gleason score ≤6, prostate-specific antigen level ≤10 ng/ml, and 1-2 positive cores. We estimated the total number of active surveillance-eligible patients in Japan based on the Japan Study Group of Prostate Cancer (J-CAP) study and the 2017 cancer statistical data. We then calculated the 5-year treatment costs of active surveillance-eligible patients using the J-CAP and PRIAS-JAPAN study data. RESULTS: In 2017, number of active surveillance-eligible patients in Japan was estimated to be 2808. The 5-year total costs of surveillance, prostatectomy, brachytherapy, radiation therapy, and hormone therapy were 1.65, 14.0, 4.61, 4.04, and 5.87 million United States dollar (USD), respectively. If 50% and 100% of the patients in each treatment group had opted for active surveillance as the initial treatment, the total treatment cost would have been reduced by USD 6.89 million (JPY 889 million) and USD 13.8 million (JPY 1.78 billion), respectively. CONCLUSION: Expanding active surveillance to eligible patients with prostate cancer helps save medical costs.

Impact of adherence to criteria on oncological outcomes of radical prostatectomy in patients opting for active surveillance: data from the PRIAS-JAPAN study.

OBJECTIVES: This study aimed to evaluate whether oncological outcomes of radical prostatectomy differ depending on adherence to the criteria in patients who opt for active surveillance. MATERIALS AND METHODS: We retrospectively reviewed the data of 1035 patients enrolled in a prospective cohort of the PRIAS-JAPAN study. After applying the exclusion criteria, 136 of 162 patients were analyzed. Triggers for radical prostatectomy due to pathological reclassification on repeat biopsy were defined as on-criteria. Off-criteria triggers were defined as those other than on-criteria triggers. Unfavorable pathology on radical prostatectomy was defined as pathological ≥T3, ≥GS 4 + 3 and pathological N positivity. We compared the pathological findings on radical prostatectomy and prostate-specific antigen recurrence-free survival between the two groups. The off-criteria group included 35 patients (25.7%), half of whom received radical prostatectomy within 35 months. RESULTS: There were significant differences in median prostate-specific antigen before radical prostatectomy between the on-criteria and off-criteria groups (6.1 vs. 8.3 ng/ml, P = 0.007). The percentage of unfavorable pathologies on radical prostatectomy was lower in the off-criteria group than that in the on-criteria group (40.6 vs. 31.4%); however, the differences were not statistically significant (P = 0.421). No significant difference in prostate-specific antigen recurrence-free survival was observed between the groups during the postoperative follow-up period (median: 36 months) (log-rank P = 0.828). CONCLUSIONS: Half of the off-criteria patients underwent radical prostatectomy within 3 years of beginning active surveillance, and their pathological findings were not worse than those of the on-criteria patients.

External Validation of a Prognostic Model Predicting Metastatic Castration-Resistant Prostate Cancer Survival in Patients Receiving Post-Docetaxel Second-Line Chemotherapy.

Introduction: The Halabi model predicts the overall survival (OS) of patients with metastatic castration-resistant prostate cancer (mCRPC) treated with second-line therapy after docetaxel. We aimed to validate this model externally with an independent cohort, outside the setting of a clinical trial. Methods: In a multi-institutional study, we included 66 patients treated with cabazitaxel after docetaxel for mCRPC. Patients were stratified according to the two- and three-risk groups of the Halabi nomogram. Kaplan-Meier and Cox proportional hazard analyses were performed to estimate survival and hazard ratios (HRs). The model performance was assessed using receiver operating characteristic curves, and the associated c-index (area under the curve [AUC]). Results: The median OS in the two-risk groups was 5.06 months in the high-risk group (n=22) and 12.9 months in the low-risk group (n=44, p<0.001). High-risk patients had an HR of 9.50 (95% confidence interval (CI) 4.12-21.6, p<0.001) compared to low-risk patients. For the three-risk groups, the median OS was 6.44 months in the high-risk group (n=15), 5.75 months in the intermediate-risk group (n=11), and 13.7 months in the low-risk group (n=40, p=0.84). Compared to low-risk patients, intermediate-risk patients had an HR of 7.49 (95% CI 3.08-20.4, p<0.001), and high-risk patients had an HR of 8.48 (95% CI, 3.39-21.7, p<0.001). The AUC was 0.72 (95% CI 0.64-0.76) for the two-risk stratification. When comparing different risks, the AUCs were 0.48 (high vs intermediate), 0.66 (high vs low), and 0.65 (intermediate vs low). Conclusions: The two-risk stratification version but not the three-risk group analysis confirmed the ability of the model to predict survival. These results support the value of the Halabi nomogram in men receiving post-docetaxel second-line chemotherapy for mCRPC.

Prognostic impact of dose reduction in androgen receptor pathway inhibitors for castration-resistant prostate cancer.

Background: Androgen receptor pathway inhibitors (ARPIs) such as abiraterone and enzalutamide have been shown to prolong survival in patients with advanced prostate cancer. However, there is limited evidence on the anticancer effect of a reduced dose of ARPIs. This study compared the prognosis in patients with chemotherapy-naïve castration-resistant prostate cancer (CRPC) between ARPI treatment with standard dose and treatment with reduced dose. Methods: Japanese patients who were treated with ARPI as first-line treatment for CRPC between 2014 and 2018 were included. The associations between dose reduction and clinicopathological factors, progression-free survival, and overall survival were investigated. Results: Of the 162 patients included, 33 (20.4%) patients had their dose reduced during ARPI treatment. In the multivariate analysis, higher PSA, abiraterone treatment, and dose reduction were significant prognostic factors for progression-free survival (PFS); however, dose reduction was not associated with overall survival. In the enzalutamide-treated group, the median PFS was 12.1 months (95% CI, 8.5-21.4 months) in the standard-dose group and 7.2 months (95% CI, 5.0-11.5 months) in the reduced-dose group (P = 0.038). Conclusion: This study suggests inferior oncological outcome when treated with reduced-dose ARPI for CRPC. Full-dose administration of ARPI for CRPC may be appropriate if feasible.

Cancer-specific and net overall survival in older patients with de novo metastatic prostate cancer initially treated with androgen deprivation therapy.

OBJECTIVE: This study aimed to assess survival outcomes in older patients with de novo metastatic prostate cancer who initially received androgen deprivation therapy. METHODS: The retrospective multicenter study included 2784 men with metastatic prostate cancer who were treated with androgen deprivation therapy between 2008 and 2017. Patients were classified into <75, 75-79, and ≥80 age groups. Propensity score matching was conducted to assess the cancer-specific survival of the groups. The 5-year net overall survival of each group was derived to evaluate relative survival compared with the general population using the Pohar-Perme estimator and the 2019 Japan Life Table. RESULTS: During the follow-up (median, 34 months), 1014 patients died, of which 807 died from metastatic prostate cancer progression. Compared with the <75 group, the cancer-specific survival of the 75-79 group was similar (hazard ratio 1.07; 95% confidence interval 0.84-1.37; P = 0.580), whereas that of the ≥80 group was significantly worse (hazard ratio 1.41; 95% confidence interval 1.10-1.80; P = 0.006). The 5-year net overall survival of the <75, 75-79, and ≥80 age groups were 0.678, 0761, and 0.718, respectively. The 5-year net overall survival of patients aged ≥80 years with low- and high-volume disease were 0.893 and 0.586, respectively, which was comparable with those in patients aged <75 years (0.872 and 0.586, respectively). CONCLUSIONS: Older metastatic prostate cancer patients aged ≥80 years had poorer cancer-specific survival compared with younger patients. Conversely, 5-year net overall survival in older patients aged ≥80 years was comparable with that in younger patients aged <75 years.

Enzalutamide + androgen deprivation therapy (ADT) versus flutamide + ADT in Japanese men with castration-resistant prostate cancer: AFTERCAB study.

Objectives: The objective of the study is to compare the efficacy and safety of alternative androgen therapy (AAT) with enzalutamide + androgen deprivation therapy (ADT) and flutamide + ADT in the treatment of Japanese men with metastatic or nonmetastatic castration-resistant prostate cancer (CRPC) who progressed despite combined androgen blockade (CAB) with bicalutamide + ADT. AAT treatment sequence was also investigated. Materials and methods: The open-label, Phase 4 AFTERCAB study (NCT02918968) was conducted from November 2016 to March 2020 in Japanese men aged ≥20 years with asymptomatic or mildly symptomatic CRPC. Patients were initially randomized to enzalutamide (160 mg/day) + ADT (enzalutamide first) or flutamide (375mg/day [125mg three times daily]) + ADT (flutamide first) as first-line therapy. Following prostate-specific antigen (PSA) progression, other disease progression, or discontinuation of first-line therapy due to an adverse event (AE), patients switched to the other treatment as second-line therapy. The primary endpoint was time to PSA progression with first-line therapy (TTPP1). Secondary endpoints included TTPP2 (TTPP1 + time to PSA progression with second-line therapy). AEs were monitored to assess safety. Results: Overall, 206 men were randomized (enzalutamide first, n = 102; flutamide first, n = 104) and stratified by study site and disease stage; 133 patients transitioned to second-line therapy (enzalutamide first, n = 48; flutamide first, n = 85). TTPP1 was significantly improved with enzalutamide first versus flutamide first (median 21.4 months vs. 5.8 months; hazard ratio [HR] 0.42; 95% confidence interval [CI] [0.29, 0.61]). TTPP2 was numerically improved with enzalutamide first versus flutamide first (median not reached vs. 21.2 months; HR 0.76; 95% CI [0.48, 1.19]). Both treatments were generally well tolerated, with AEs consistent with their known safety profiles. Conclusion: First-line AAT with enzalutamide + ADT provided a significant improvement in time to PSA progression versus flutamide + ADT. Enzalutamide + ADT may therefore be the preferred first-line AAT option in Japanese men with metastatic or nonmetastatic CRPC who progress despite CAB with bicalutamide + ADT.

Radiotherapy plus androgen deprivation therapy for prostate-specific antigen persistence in lymph node-positive prostate cancer.

The treatment for lymph node involvement (LNI) after radical prostatectomy (RP) has not been established. This study aimed to reveal the outcomes of various management strategies among patients with LNI after RP. Retrospectively, 561 patients with LNI after pelvic lymph node dissection (PLND) with RP treated between 2006 and 2019 at 33 institutions participating in the Japanese Urological Oncology Group were investigated. Metastasis-free survival (MFS) was the primary outcome. Patients were stratified by prostate-specific antigen (PSA) persistence after RP. Cox regression models were used to analyze the relationships between clinicopathological characteristics and survival. Survival analyses were conducted using the Kaplan-Meier method and log-rank test with or without propensity score matching. Prognoses, including MFS and overall survival, were prominently inferior among patients with persistent PSA compared with those without persistent PSA. In multivariate analysis, androgen deprivation therapy (ADT) plus radiotherapy (RT) was associated with better MFS than ADT alone among patients with persistent PSA (hazard ratio = 0.37; 95% confidence interval = 0.15-0.93; p = 0.034). Similarly, MFS and overall survival were significantly better for ADT plus RT than for ADT alone among patients with persistent PSA after propensity score matching. This study indicated that PSA persistence in LNI prostate cancer increased the risk of poor prognoses, and intensive treatment featuring the addition of RT to ADT might improve survival.