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.

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.

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.

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.

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.

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.

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.

Differential prognostic impact of complete blood count-related parameters by prior use of novel androgen receptor pathway inhibitors in docetaxel-treated castration-resistant prostate cancer patients.

There are multiple reports on the value of complete blood count (CBC)-related parameters on prognosis in docetaxel-treated castration-resistant prostate cancer (CRPC) patients before the emergence of androgen receptor pathway inhibitors (ARPIs). We investigated the prognostic significance of CBC-related parameters in docetaxel-treated CRPC patients. Patients treated with docetaxel chemotherapy for CRPC between 2008 and 2018 were included. We analyzed the relevance of CBC-related parameters to oncological prognosis in docetaxel chemotherapy, associated with prior use of novel ARPIs. Among 144 Japanese men treated with docetaxel, 49 men (34.0%) had already received ARPI therapy. A high neutrophil-lymphocyte ratio (NLR) was a prognostic factor for poor progression-free survival and overall survival (OS) in both univariate and multivariate analyses. In addition, a low hemoglobin (Hb) level and a high systemic immune-inflammation index (SII) were prognostic factors of poor OS in univariate analysis. Hb level was a prognostic factor of OS in both ARPI-naive and ARPI-treated patients. However, a high NLR and SII were only associated with a poor prognosis in ARPI-naive but not in ARPI-treated patients. Hb, NLR, and SII have been suggested to be prognosticators in docetaxel-treated CRPC patients. The differential prognostic value of NLR and SII between ARPI-naive and ARPI-treated patients may require caution when using these markers in docetaxel-treated CRPC patients.

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.

Real-world use of enzalutamide in men with nonmetastatic castration-resistant prostate cancer in Japan.

BACKGROUND: The purpose of the study is to evaluate real-world effectiveness and safety of enzalutamide in men with nonmetastatic castration-resistant prostate cancer (nmCRPC) in Japan. METHODS: This was a retrospective evaluation of medical records from men in Japan who started enzalutamide treatment from November 1, 2014, to March 31, 2018, and received androgen deprivation therapy throughout. The primary endpoint was time to prostate-specific antigen (PSA) progression. Secondary endpoints included PSA response rate, time to first use of new antineoplastic therapy, time to first use of cytotoxic chemotherapy, and enzalutamide treatment duration. An exploratory analysis of metastasis-free survival (MFS) was also performed. Adverse events (AEs) were analyzed to assess safety. RESULTS: Based on data from medical records of 205 men in Japan, median time to PSA progression was 27 months (95% confidence interval [CI] 19-not reached [NR]), with 82.5% and 52.0% of men achieving PSA response rates of ≥ 50% and ≥ 90%, respectively. Median time to first use of new antineoplastic therapy was 36 months (95% CI 27-NR) and median enzalutamide treatment duration was 13 months (interquartile range: 7-24). Median time to first use of cytotoxic chemotherapy was NR (95% CI 41-NR). Median MFS was 29 months (95% CI 23-35). In total, 51.7% of men experienced AEs, with malaise (18.5%), decreased appetite (10.7%), and nausea (4.9%) the most frequently reported. CONCLUSIONS: This is the first study to demonstrate the real-world effectiveness and safety of enzalutamide in men with nmCRPC in Japan, further informing healthcare providers about available treatment options for this patient population.

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.

Deferred radical prostatectomy in patients who initially elected for active surveillance: a multi-institutional, prospective, observational cohort of the PRIAS-JAPAN study.

BACKGROUND: This study aimed to evaluate the pathological findings and oncological outcomes of deferred radical prostatectomy in patients who initially elected for active surveillance in a Japanese cohort. METHODS: We retrospectively analyzed data collected from a multi-institutional prospective observational cohort of the Prostate Cancer Research International: Active Surveillance-JAPAN study between January 2010 and September 2020. Triggers for radical prostatectomy were disease progression based on pathological findings of repeat biopsy and patients' request. The primary end point was evaluation of prostate-specific antigen recurrence-free survival. Secondary end points were overall survival and comparison of pathological and oncological outcomes between patients stratified into immediate or late radical prostatectomy group by time to radical prostatectomy. RESULTS: Overall, 162 patients (15.7%) with prostate cancer underwent initial active surveillance followed by radical prostatectomy. The median time to radical prostatectomy was 18 months (interquartile range 14-43.3), and the median postoperative follow-up was 32 months (interquartile range 14-57.5). Prostate-specific antigen recurrence was observed in eight patients (4.9%). The 3-year prostate-specific antigen recurrence-free survival rate was 96.9%. The 5-year overall survival rate was 100%; however, one patient died of another cause. There were no significant differences in pathological findings between immediate and late radical prostatectomy groups. No significant difference in prostate-specific antigen recurrence-free survival was found between the two groups (log-rank p = 0.34). CONCLUSIONS: Radical prostatectomy after active surveillance, as an initial treatment option, does not lead to loss of curative chances in Japanese patients with early-stage prostate cancer in the short follow-up period.

Predictive factors of survival outcomes in first-line therapy for metastatic castration-resistant prostate cancer.

OBJECTIVES: To investigate predictive factors of survival of metastatic castration-resistant prostate cancer patients undergoing first-line treatment with androgen receptor pathway inhibitors or docetaxel. METHODS: Japanese patients with metastatic castration-resistant prostate cancer treated with androgen receptor pathway inhibitor or docetaxel between 2008 and 2018 were included. The differential impact of various clinicopathological factors on the outcome, including progression-free survival and overall survival, was compared between treatment with androgen receptor pathway inhibitor and docetaxel. RESULTS: Of 254 patients with metastatic castration-resistant prostate cancer, 119 (46.9%) and 135 (53.2%) were treated with androgen receptor pathway inhibitor and docetaxel, respectively. The multivariate analysis showed that androgen receptor pathway inhibitor was an independent prognostic factor for better progression-free survival (hazard ratio 0.62, 95% confidence interval 0.42-0.92, P = 0.016) and overall survival (hazard ratio 0.61, 95% confidence interval 0.41-0.93, P = 0.021), compared with docetaxel. Pretreatment prostate-specific antigen levels and time to castration-resistant prostate cancer were differentially associated with progression-free survival and overall survival between androgen receptor pathway inhibitor or docetaxel. In patients who presented <6 months to castration-resistant prostate cancer, progression-free survival was shorter in those treated with androgen receptor pathway inhibitor (median 1.1 months, 95% confidence interval 0.2-2.8 months) compared with those who received docetaxel (median 5.0 months, 95% confidence interval 1.8-6.7 months; P = 0.014). CONCLUSIONS: First-line therapy with androgen receptor pathway inhibitor is associated with a better prognosis when compared with docetaxel, even after adjustment for prognostic factors. However, a shorter time to castration-resistant prostate cancer is associated with better progression-free survival for patients receiving docetaxel, suggesting that docetaxel is the preferred option for patients with a shorter time to castration-resistant prostate cancer.

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.

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.

Efficacy of combined androgen blockade therapy in patients with metastatic hormone-sensitive prostate cancer stratified by tumor burden.

OBJECTIVE: To determine the effect of combined androgen blockade with a first-generation anti-androgen on the prognoses of metastatic hormone-sensitive prostate cancer patients stratified by tumor burden. METHODS: We retrospectively analyzed the cases of metastatic hormone-sensitive prostate cancer patients who were treated with androgen deprivation therapy in 2008-2017 at 30 institutions in Japan. To compare the overall survival and progression-free survival rates of the patients treated with castration monotherapy and combined androgen blockade, we carried out a Cox proportional hazards regression analysis using both inverse probability of treatment weighting and instrumental variables methods. High-burden disease was defined as the presence of four or more bone metastases and/or visceral metastasis. RESULTS: Of 2048 patients, 702 (34.3%) and 1346 (65.7%) patients were classified as the low- and high-burden groups, respectively. In each group, >80% of the patients were treated with combined androgen blockade. Although there was no significant between-group difference in the overall survival according to the androgen deprivation therapy method, in the high-burden group the progression-free survival of the combined androgen blockade-treated patients was significantly better than that of patients treated with castration monotherapy: inverse probability of treatment weighting method, hazard ratio 0.49, 95% confidence interval 0.34-0.71; instrumental variables method, hazard ratio 0.80, 95% confidence interval 0.60-0.98. CONCLUSION: In the high-burden group, combined androgen blockade with a first-generation anti-androgen resulted in superior progression-free survival compared with castration monotherapy. For well-selected metastatic hormone-sensitive prostate cancer patients, the use of combined androgen blockade might still have some suitable scenarios.

Novel metastatic burden-stratified risk model in de novo metastatic hormone-sensitive prostate cancer.

The metastatic burden is a critical factor for decision-making in the treatment of metastatic hormone-sensitive prostate cancer (HSPC). This study aimed to develop and validate a novel risk model for survival in patients with de novo low- and high-burden metastatic HSPC. The retrospective observational study included men with de novo metastatic prostate cancer who were treated with primary androgen-deprivation therapy at 30 institutions across Japan between 2008 and 2017. We created a risk model for overall survival (OS) in the discovery cohort (n = 1449) stratified by the metastatic burden (low vs high) and validated its predictive ability in a separate cohort (n = 951). Based on multivariate analyses, lower hemoglobin levels, higher Gleason grades, and higher clinical T-stage were associated with poor OS in low-burden disease. Meanwhile, lower hemoglobin levels, higher Gleason grade group, liver metastasis, and higher extent of disease scores in bone were associated with poor OS in patients with high-burden disease. In the discovery and validation cohorts, the risk model using the aforementioned parameters exhibited excellent discriminatory ability for progression-free survival and OS. The predictive ability of this risk model was superior to that of previous risk models. Our novel metastatic burden-stratified risk model exhibited excellent predictive ability for OS, and it is expected to have several clinical uses, such as precise prognostic estimation.

Differential prognostic factors in low- and high-burden de novo metastatic hormone-sensitive prostate cancer patients.

Metastatic burden is a critical factor for therapy decision-making in metastatic hormone-sensitive prostate cancer. The present study aimed to identify prognostic factors in men with high- or low-metastatic burden treated with primary androgen-deprivation therapy. The study included 2450 men with de novo metastatic prostate cancer who were treated with primary androgen-deprivation therapy at 30 institutions across Japan between 2008 and 2017. We investigated the prognostic value of various clinicopathological parameters for progression-free survival (PFS) and overall survival (OS) in patients stratified by low- or high-metastatic burden. Among the 2450 men, 841 (34.3%) and 1609 (65.7%) were classified as having low- and high-metastatic burden, respectively. Median PFS of the low- and high-burden groups were 44.5 and 16.1 months, respectively, and the median OS was 103.2 and 62.7 months, respectively. Percentage of biopsy-positive core, biopsy Gleason grade group, T-stage, and N-stage were identified to be differentially prognostic. M1a was associated with worse PFS than was M1b in the low-burden group, whereas lung metastasis was associated with better PFS and OS than was M1b in the high-burden group. Differential prognostic factors were identified for patients with low- and high-burden metastatic prostate cancer. These results may assist in decision-making to select the optimal therapeutic strategies for patients with different metastatic burdens.

Efficacy and Safety of 4-Weekly Docetaxel for Castration-Resistant Prostate Cancer.

We investigated the efficacy and safety profiles of 4-weekly docetaxel for castration-resistant prostate cancer. Patients treated with ≥2 courses of docetaxel chemotherapy (median, 70 mg/m2) between 2008 and 2018 were included. Among 125 Japanese men, 40 (32.0%) and 85 (68.0%) were treated with 3-weekly and 4-weekly regimens, respectively. In the 4-weekly regimen, the risks of progression, treatment failure, and any-cause mortality were comparable to those in the 3-weekly regimen. The incidences of severe adverse events were also similar between the 3-weekly and 4-weekly regimens. These data suggest that the 4-weekly regimen may be an acceptable option for selected patients.