Oncological outcome of docetaxel-based chemotherapy for Japanese men with metastatic castration-resistant prostate cancer

The prognostic value of Eastern Cooperative Oncology Group performance status on overall survival among patients with metastatic prostate cancer: a systematic review and meta-analysis

Background

There is heterogeneity in the literature regarding the strength of association between Eastern Cooperative Oncology Group performance status (ECOG PS) and mortality. We conducted a systematic review and meta-analysis of studies reporting the prognostic value of ECOG PS on overall survival (OS) in metastatic prostate cancer (mPC).

Methods

PubMed was searched from inception to March 21, 2022. A meta-analysis pooling the effect of ECOG PS categories (≥2 vs. <2, 2 vs. <2, and ≥1 vs. <1) on OS was performed separately for studies including patients with metastatic castration-resistant prostate cancer (mCRPC) and metastatic castration-sensitive prostate cancer (mCSPC) using a random-effects model. Analyses were stratified by prior chemotherapy and study type.

Results

Overall, 75 studies, comprising 32,298 patients, were included. Most studies (72/75) included patients with mCRPC. Higher ECOG PS was associated with a significant increase in mortality risk, with the highest estimate observed among patients with mCRPC with an ECOG PS of ≥2 versus <2 (hazard ratio [HR]: 2.10, 95% confidence interval [CI]: 1.87-2.37). When stratifying by study type, there was a higher risk estimate of mortality among patients with mCRPC with an ECOG PS of ≥1 versus <1 in real-world data studies (HR: 1.98, 95% CI: 1.72-2.26) compared with clinical trials (HR: 1.32, 95% CI: 1.13-1.54; p < 0.001). There were no significant differences in the HR of OS stratified by previous chemotherapy.

Conclusion

ECOG PS was a significant predictor of OS regardless of category, previous chemotherapy, and mPC population. Additional studies are needed to better characterize the effect of ECOG PS on OS in mCSPC.

The Pretherapeutic Neutrophil-to-Lymphocyte Ratio for Docetaxel-Based Chemotherapy Is Useful for Predicting the Prognosis of Japanese Patients with Castration-Resistant Prostate Cancer

Introduction and Objectives

The neutrophil-to-lymphocyte ratio (NLR) has been suggested as a simple marker of the systemic inflammatory response in critical care patients. The NLR can be easily calculated from routine complete blood counts in the peripheral blood. This parameter has been reported to be an independent prognosticator for some solid malignancies. In the present study, we examined the importance of the NLR as a prognostic marker for castration-resistant prostate cancer (CRPC) patients who received docetaxel- (DOC-) based chemotherapy.

Methods

We analyzed a total of 73 patients who received DOC chemotherapy for CRPC in Yokohama City University Medical Center and affiliated hospitals. Complete blood cell counts were performed, and the NLR was calculated using the neutrophil and lymphocyte counts obtained on the same day or a few days before the initiation of DOC chemotherapy. We determined the NLR cutoff value based on the sensitivity and specificity levels derived from area under the receiver operator characteristic curves for death.

Results

The median overall survival (OS) after DOC was 21.0 months (range: 2.0–51.0). The median OS was shorter in patients with a high NLR (≥2.59) than in those with a low NLR (<2.59) (12.0 versus 31.6 months, p=0.001). In the multivariate analysis, the NLR and lymph node (LN) metastasis were independent predictors of the OS (hazard ratio 3.643, p=0.001; hazard ratio 2.184, p=0.038, respectively).

Conclusions

The higher NLR group showed a significantly poorer OS than the lower NLR group. Pre-DOC NLR might be a new marker for predicting the prognosis of patients who receive DOC chemotherapy.

No survival benefit found after extended treatment with docetaxel for patients with castration-resistant prostate cancer

BACKGROUND

Docetaxel (DOC) has been widely accepted as a therapeutic option for castration-resistant prostate cancer (CRPC). Evidence-based clinical guidelines have stipulated its use up to 10 cycles in most health care systems. There has been a paucity of information regarding potential benefits of its use over 10 cycles. The purpose of this study is to re-examine the rationale for the clinical guidelines concerning cycles of DOC in CRPC.

METHODS

Between July 2007 and July 2016, a total of 122 CRPC patients received at least five cycles of DOC at Jikei University and its affiliate hospitals. Doses of DOC (75 mg/m ² ) were administered every 3 to 4 weeks. Clinical outcomes between patients receiving extended cycles of DOC (≥11 cycles, extended [ex]-DOC group) were compared to those receiving fewer (≤10 cycles, short-DOC group). A subgroup of patients who had discontinued DOC owing to adverse events, but whose disease did not progress, were also considered for comparison (adverse events [AE] group). Overall survival from the induction of DOC was the primary outcome measure. Univariate and multivariate analyses were conducted to analyze variables associated with overall survival.

RESULTS

The ex- and short-DOC groups included 80 and 42 patients, respectively. Most baseline demographics did not differ between groups. However, in the short-DOC group more patients had received abiraterone acetate and/or enzalutamide before chemotherapy, age at DOC induction was younger, and lactate dehydrogenase at DOC induction was higher. Overall survival was significantly longer in the ex-DOC group compared to the short-DOC group (median, 53 and 27 months, respectively; P = .04). A subgroup of 22 patients in AE group was compared to compensate for potential bias. Overall survival from the induction of DOC was comparable between AE group and ex-DOC groups (median, 53 vs 53 months, respectively; P = 0.87). Univariate and multivariate analyses did not show any advantage of extended use of DOC on patient survival.

CONCLUSIONS

The results of this study failed to show the survival benefit of extended use of DOC over 10 cycles in CRPC patients in the era of innovative drugs such as abiraterone acetate, enzalutamide, and cabazitaxel. Further prospective studies are required to confirm our findings.

Prognostic models for predicting overall survival in metastatic castration-resistant prostate cancer: a systematic review

PURPOSE

Prognostic models are developed to estimate the probability of the occurrence of future outcomes incorporating multiple variables. We aimed to identify and summarize existing multivariable prognostic models developed for predicting overall survival in patients with metastatic castration-resistant prostate cancer (mCRPC).

METHODS

The protocol was prospectively registered (CRD42017064448). We systematically searched Medline and reference lists up to May 2018 and included experimental and observational studies, which developed and/or internally validated prognostic models for mCRPC patients and were further externally validated or updated. The outcome of interest was overall survival. Two authors independently performed literature screening and quality assessment.

RESULTS

We included 12 studies that developed models including 8750 patients aged 42-95 years. Models included 4-11 predictor variables, mostly hemoglobin, baseline PSA, alkaline phosphatase, performance status, and lactate dehydrogenase. Very few incorporated Gleason score. Two models included predictors related to docetaxel and mitoxantrone treatments. Model performance after internal validation showed similar discrimination power ranging from 0.62 to 0.73. Overall survival models were mainly constructed as nomograms or risk groups/score. Two models obtained an overall judgment of low risk of bias.

CONCLUSIONS

Most models were not suitable for clinical use due to methodological shortcomings and lack of external validation. Further external validation and/or model updating is required to increase prognostic accuracy and clinical applicability prior to their incorporation in clinical practice as a useful tool in patient management.

Burden of illness of chemotherapy in castration-resistant prostate cancer patients in Japan: a retrospective database analysis

OBJECTIVE

The objective was to assess the burden of chemotherapy for castration-resistant prostate cancer (CRPC) in Japan.

METHODS

Utilizing a large administrative hospital database we compared a set of outcome measures 12 months before and after initiation of chemotherapy, namely total medical costs, number of outpatient visits, number of hospital admissions and number of days spent in hospital.

RESULTS

A total of 598 CRPC patients were identified in the database. Total healthcare costs increased from 143,578 Japanese Yen (JPY) per patient per month (PPPM), before chemotherapy, to 333,628 JPY after start of chemotherapy. The number of hospital admissions increased by 280%, and the number of days spent in hospital by 380%.

CONCLUSIONS

The overall costs of chemotherapy for patients diagnosed with castration-resistant prostate cancer in Japan are high. Our findings can serve as a basis for health economic evaluations.

Low-dose docetaxel, estramustine and prednisolone combination chemotherapy for castration-resistant prostate cancer

The objective of this study was to report our experience with weekly low-dose docetaxel (DOC) chemotherapy for patients with castration-resistant prostate cancer (CRPC). From 2007 to 2014, 39 consecutive patients received weekly low-dose DOC; the oncological effectiveness, side effects and tolerability were prospectively analyzed. The median patient age, serum prostate-specific antigen (PSA) level and Gleason score at diagnosis of prostate cancer were 71 years (range, 55-83 years), 187 ng/ml (range, 2.0-1711 ng/ml) and 8 (range, 5-10), respectively. The median number of cycles of DOC was 7 (range, 1-45 cycles). Of the 39 patients, the PSA level decreased by >50% in 13 (33%). In the multivariate analysis of prediction of patient overall survival, a decrease of the PSA level to <50% was a significant predictor (hazard ratio = 6.913; 95% confidence interval: 1.147-41.669; P=0.035). The median cancer-specific overall survival from the diagnosis of CRPC was 16.7 months (range, 2-54 months). Grade 3 toxicities were observed in 5 patients (13%); specifically, limb edema, nausea and hepatic disorders were detected in 2 (5%), 2 (5%) and 1 patient (3%), respectively. Treatment-related death (grade 5) occurred in 1 patient due to interstitial pneumonia after two courses of chemotherapy. The chemotherapy was completed in the majority of the patients (n=37, 94.8%) in the outpatient department, without interruption. These findings suggest that weekly low-dose DOC is feasible and safe for selected patients with CRPC, without treament with novel agents, such as abiraterone, enzalutamide and cabazitaxel.

Prognostic value of a computer-aided diagnosis system involving bone scans among men treated with docetaxel for metastatic castration-resistant prostate cancer

BACKGROUND

The bone scan index (BSI), which is obtained using a computer-aided bone scan evaluation system, is anticipated to become an objective and quantitative clinical tool for evaluating bone metastases in prostate cancer. Here, we assessed the usefulness of the BSI as a prognostic factor in patients with metastatic castration-resistant prostate cancer (mCRPC) treated using docetaxel.

METHODS

We analyzed 41 patients who received docetaxel for mCRPC. The Bonenavi system was used as the calculation program for the BSI. The utility of the BSI as a predictor of overall survival (OS) after docetaxel was evaluated. The Cox proportional hazards model was used to investigate the association between clinical variables obtained at docetaxel treatment, namely PSA, patient age, liver metastasis, local therapy, hemoglobin (Hb), lactase dehydrogenase (LDH), albumin (Alb), PSA doubling time, and BSI and OS.

RESULTS

The median OS after docetaxel therapy was 17.7 months. Death occurred in 22 (53.7%) patients; all deaths were caused by prostate cancer. In multivariate analysis, three factors were identified as significant independent prognostic biomarkers for OS after docetaxel; these were liver metastases (yes vs no; HR, 3.681; p = 0.026), Alb (<3.9 vs ≥ 3.9; HR, 3.776; p = 0.020), and BSI (>1% vs ≤ 1%; HR, 3.356; p = 0.037). We evaluated the discriminatory ability of our models including or excluding the BSI by quantifying the c-index. The BSI improved the c-index from 0.758 to 0.769 for OS after docetaxel. CRPC patients with a BSI >1 had a significantly shorter OS than patients with a BSI ≤ 1 (p = 0.029).

CONCLUSIONS

The BSI, liver metastases and Alb were independent prognostic factors for OS after docetaxel. The BSI might be a useful tool for risk stratification of mCRPC patients undergoing docetaxel treatment.

High neutrophil-to-lymphocyte ratio predicts poor clinical outcome in patients with castration-resistant prostate cancer treated with docetaxel chemotherapy

OBJECTIVE

To evaluate the prognostic significance of the neutrophil-to-lymphocyte ratio in patients receiving chemotherapy with docetaxel for castration-resistant prostate cancer.

METHODS

A total of 57 castration-resistant prostate cancer patients treated between 2009 and 2014 were included in the present retrospective study. All patient data, including clinicopathological factors, were assessed. Univariate and multivariate Cox regression models were used to predict overall survival and progression-free survival after chemotherapy initiation.

RESULTS

The median overall survival and progression-free survival were determined as 19.0 months (range 1-61 months) and 10.0 months (range 1-56 months), respectively. The cut-off level of the neutrophil-to-lymphocyte ratio was set as the median value of 3.5 among all patients in this study. In Kaplan-Meier analysis, the median overall survival and progression-free survival were shorter in patients with a high neutrophil-to-lymphocyte ratio compared with those with a low neutrophil-to-lymphocyte ratio (15 vs 20 months, P = 0.0125; and 9.5 vs 15 months, P = 0.0132, respectively). The overall survival and progression-free survival periods in patients with a high neutrophil-to-lymphocyte ratio were significantly shorter than those of patients with a low neutrophil-to-lymphocyte ratio (P = 0.0178 and 0.0176, respectively). In the multivariate analysis, a high neutrophil-to-lymphocyte ratio was an independent predictor of overall survival and progression-free survival (hazard ratio 2.728, 95% confidence interval 1.05-7.09, P = 0.039; and hazard ratio 2.376, 95% confidence interval 1.12-5.06, P=0.024, respectively).

CONCLUSION

The present study results suggest that the neutrophil-to-lymphocyte ratio is a useful prognostic factor in patients with castration-resistant prostate cancer treated by docetaxel chemotherapy. These findings might be useful in determining treatment strategies in the future.

A phase 2 trial of abiraterone acetate in Japanese men with metastatic castration-resistant prostate cancer and without prior chemotherapy (JPN-201 study)

Objective

Abiraterone acetate has been approved in >70 countries for chemotherapy-naïve metastatic castration-resistant prostate cancer patients. Efficacy and safety of abiraterone acetate (1000 mg/once daily) with prednisolone (5 mg/twice daily) in chemotherapy-naïve Japanese patients with metastatic castration-resistant prostate cancer was evaluated.

Methods

Men, ≥20 years, with prostate-specific antigen levels of ≥5 ng/ml and evidence of progression were enrolled in this Phase 2, multicenter, open-label study. Primary efficacy endpoint was proportion of patients achieving a prostate-specific antigen decline of ≥50% from baseline (prostate-specific antigen response) after 12 week of treatment. Secondary efficacy endpoints and safety were assessed.

Results

A confirmed prostate-specific antigen response was observed in 29/48 (60.4%) patients by week 12; lower limit of two-sided 90% confidence interval was >35% (threshold response rate), demonstrating efficacy of abiraterone acetate. Secondary efficacy endpoints: prostate-specific antigen response rate during treatment period: 62.5%; objective radiographic response, partial response: 4/18 (22.2%) patients; complete response: none; stable disease: 11/18 (61.1%) patients; median percent change in prostate-specific antigen level from baseline at Week 12: −66.62%. Median prostate-specific antigen response duration and progression-free survival were not reached, and median radiographic progression-free survival was 253 days. Of 31/48 (64.6%) patients experienced adverse events of special interest; most common was hepatic function abnormality (37.5%, Grade 3: 10.4%). One Grade 3 hypertension was the only mineralocorticoid adverse event >Grade 1/2.

Conclusions

Efficacy of abiraterone acetate plus prednisolone was demonstrated by decline in prostate-specific antigen levels with evidence of antitumor activity by radiography in Japanese patients with chemotherapy-naïve metastatic castration-resistant prostate cancer. Abiraterone acetate plus prednisolone had an acceptable safety profile.

Clinical trial registration no

NCT01756638.

[Clinical study of long-term docetaxel based chemotherapy treatment for patients with castration-resistant prostate cancer]

PURPOSE

To evaluate long-term continuous administration of docetaxel (DOC), over survival rate, PSA level and adverse effects were analyzed, retrospectively. We also compared the results of long-term treatment group and short-term treatment group.

MATERIAL AND METHODS

This study reported that 14 cases of long-term continuous administration of DOC consisting of 11 or more cycles among 51 patients of castration-resistant prostate cancer (CRPC) treated with DOC from October 2008 to September 2013 at our institution, retrospectively. Nineteen patients who had treated with DOC 10 or less cycles were defined as short-term dose group, and both groups were compared. DOC was administered every 3 to 4 weeks at 60 to 70 mg/m2, and was treated with prednisolone at 10 mg/day as a general.

RESULTS

The median number of treatment cycles was 15. Thirteen cases showed a decrease in PSA levels and 10 cases showed a decrease in PSA levels of 50% or more, the 1-year survival rate of long-term dose and short-term dose group were 100% and 16%. Adverse effects of grade 3 or lower consisted of leukocytopenia in 85% and thrombocytopenia in 28%, however, grade 4 or higher were not observed in long-term dose group. In multivariable analysis of parameters, long-term treatment was related to PSA levels at start of treatment and ALP levels.

CONCLUSION

Forty-two percent of patients who have CRPC at our institution undergo long-term DOC based chemotherapy treatment It may be suggested that long-term DOC based chemotherapy for some cases contribute to extend survival time with no serious adverse events.

Docetaxel based chemotherapy in the treatment of patients with castration resistant prostate cancer

INTRODUCTION

Docetaxel administered every 3- weeks is the standart treatment of castration resistant prostate cancer (CRPC) but it is associated with dose limiting toxicities. We analyzed the efficacy and tolerability of 3- weekly and weekly docetaxel in a Turkish cohort of CRPC patients with a special emphasis on the elderly patients.

MATERIALS AND METHODS

A retrospective analyses of 45 patients who received either 3- weekly or weekly docetaxel in a single urologic oncology clinic was performed. Response to therapy, toxicity and overall survival rates were evaluated.

RESULTS

The mean age of patients was 70.0 (±8.8) years. Complete or partial PSA response was obtained in 45% of patients. The median overall survival was 20,0 months (SE 6.46; 95% CI 7,3-32,6). Absence of metastasis, time to CRPC>10 months, DP 75mg/m2 once every three weeks and PSA<50% at the end of the third cycle were associated with better overall survival. There was no significant survival difference between the patients aged 75 or older versus younger ones. The most common hematological toxicity was leukopenia which was dose limiting in only one patient.

CONCLUSION

Administration of standart 3-weekly docetaxel is well tolerated in this relatively old cohort of Turkish CRPC patients and weekly administration can be a reasonable alternative in frail patients not only to prolong survival but also to palliate disease symptoms.

Clinical predictor of survival following docetaxel-based chemotherapy

Prostate cancer (PCa) is the most common type of cancer in males in the USA and the incidence is increasing. For castration-resistant PCa (CRPC), previous studies have identified docetaxel-based chemotherapy as the first-line therapy. In the present study, the efficacy of docetaxel-based chemotherapy was investigated in a population of patients with CRPC. This study included 26 individuals (mean age, 73 years) with CRPC who were patients between July 2007 and October 2012 at the Kaohsiung Medical University Hospital (Kaohsiung, Taiwan). The regimen consisted of intravenous docetaxel (70 mg/m²) once every four weeks plus oral prednisolone (5 mg) twice daily for five days. Prostate-specific antigen (PSA) response (defined as a PSA decrease of >50% over four weeks), time to PSA progression, PCa-specific survival and overall survival (OS) were evaluated. For these 26 patients, the mean PSA level prior to chemotherapy treatment was 335.58 ng/ml. During follow-up, the average number of cycles of chemotherapy was approximately seven and 15 patients (58%) achieved a PSA response. PSA response was found to significantly correlate with OS and PCa-specific survival (P=0.014 and P=0.028, respectively). The mean value of the PSA nadir level was 89.97 ng/ml and time to PSA nadir was five months. The most common adverse event was leucopenia, which affected 88% of the patients. The results indicated that the length of time to PSA nadir and the occurrence of leucopenia may impact the PSA response. The docetaxel-based chemotherapy was a feasible and effective treatment regimen in patients with CRPC. However, the occurrence of adverse events, particularly the high incidence of leucopenia, may be cause for concern.

Combination of hemoglobin, alkaline phosphatase, and age predicts optimal docetaxel regimen for patients with castration-resistant prostate cancer

BACKGROUND

We aimed to find the prognostic factors predicting overall survival (OS) in patients with castration-resistant prostate cancer (CRPC) who had docetaxel (DTX) chemotherapy, and to construct a model predicting the optimum number of cycles of DTX.

METHODS

A total of 279 CRPC patients who received DTX (≥50 mg/m(2)) every 3-4 weeks were studied retrospectively. Prognostic factors predicting treatment cycles as well as OS were analyzed, and a risk table for predicting treatment cycles was constructed.

RESULTS

The longer treatment group (>10 cycles) had a significantly longer OS than the standard treatment group (p < 0.0001). Multivariate analysis demonstrated that a decrease of ≥50 % in prostate-specific antigen (PSA), serum markers at the start of DTX therapy [PSA, alkaline phosphatase (ALP), and C-reactive protein (CRP)], and the number of DTX courses were independent predictors of OS. The risk table employing the combination of three factors [ALP (cut-off 189 IU/L), hemoglobin (11.3 g/dL), and age (65 years) at the start of DTX therapy], and scoring based on the hazard ratio of each risk factor (ALP 4, hemoglobin 2, age 3) could effectively predict the probability of the length of DTX therapy, with lower score (0-6) predicting >10 cycles, and higher score (7-9) predicting ≤5 cycles (p < 0.0001). No significant difference was found regarding grade 3/4 adverse events between the two groups.

CONCLUSION

A model using three factors prior to chemotherapy may be beneficial for deciding the duration of DTX therapy in patients with CRPC.

Docetaxel: a review of its use for the first-line treatment of advanced castration-resistant prostate cancer

Docetaxel (Taxotere®) is a well established anti-mitotic chemotherapy agent. Among other therapeutic indications, docetaxel plus prednisone is indicated for first-line chemotherapy in patients with castration-resistant prostate cancer (CRPC). Docetaxel every 3 weeks plus continuous prednisone has been standard first-line chemotherapy in CRPC since demonstrating improved survival compared with the previous standard regimen, mitoxantrone plus prednisone, in the phase III TAX 327 trial in 2004. Since that time, docetaxel has been combined with various agents that demonstrated additive or synergistic activity in preclinical studies in an effort to further improve outcomes, but to date, overall survival has not been extended compared with docetaxel plus prednisone. However, several promising agents are emerging with a potential role in docetaxel-based combinations based on efficacy and manageable toxicity, including bevacizumab, dasatinib and atrasentan. In the TAX 327 trial, neutropenia was relatively common in the group receiving 3-weekly docetaxel plus prednisone, but infection was rare. The tolerability of a weekly docetaxel regimen also administered in this trial was not significantly different to that of the 3-weekly regimen, except for a lower incidence of grade 3 or 4 neutropenia. However, weekly or 2-weekly docetaxel administration schedules may have a place in very elderly or frail patients in order to improve tolerability compared with the 3-weekly regimen. In conclusion, docetaxel every 3 weeks plus prednisone remains the optimum first-line chemotherapy for most patients with advanced CRPC until such time that ongoing research with docetaxel and emerging therapeutic agents can demonstrate improved survival.

Reduced-dose docetaxel for castration-resistant prostate cancer has no inferior impact on overall survival in Japanese patients

BACKGROUND

In clinical practice, an adapted regimen with dose reduction is applied to castration-resistant prostate cancer (CRPC) treated with docetaxel because of its toxicity. However, there are few reports on the impact of dose reduction on survival.

METHODS

Fifty-seven patients with CRPC treated with first-line docetaxel in a single institution from 2005 to 2008 were evaluated retrospectively.

RESULTS

The median follow-up period was 20.5 months. Twenty-eight patients (49 %) received a standard 60 mg/m(2) regimen (SR), and 29 patients (51 %) received an adapted regimen (AR) with dose reduction. There was no difference in their baseline characteristics. The prostate-specific antigen response rates were not significantly different between the SR and AR groups (50 vs. 62 %, p = 0.36). Progression-free survival (PFS) and overall survival (OS) were also not significantly different between the groups (PFS 5.3 vs. 7.3 months, p = 0.39; OS 26.4 vs. 27.1 months, p = 0.53, respectively). No significant difference in the incidence of grade 3 or 4 adverse events was noted between the groups (89 vs. 83 %, p = 0.70). In multivariate analysis, hemoglobin and alkaline phosphatase were significant predictive factors for OS (hazard ratios 2.81 and 2.39, p = 0.012 and 0.024, respectively).

CONCLUSIONS

A reduced-dose regimen of docetaxel has no inferior impact on OS. Further studies on the optimal dose of docetaxel for Japanese patients are required.

Significance of docetaxel-based chemotherapy as treatment for metastatic castration-resistant prostate cancer in Japanese men over 75 years old

OBJECTIVES

The objective of this study was to evaluate the significance of docetaxel-based chemotherapy in elderly Japanese men with metastatic castration-resistant prostate cancer (CRPC).

MATERIALS AND METHODS

This study included a total of 159 consecutive patients aged≥75 years with mCRPC who were treated with docetaxel-based chemotherapy. The efficacy and tolerability of this therapy were retrospectively analyzed.

RESULTS

In these 159 patients, the median age and prostate-specific antigen (PSA) level before docetaxel-based chemotherapy were 78 years and 44.0 ng/ml, respectively. Of these patients, 42 (26.4%) and 117 (73.6%) received docetaxel as a weekly (30 mg/m2) and 3-weekly (70 mg/m2) regimen, respectively, and estramustine was administered combining with docetaxel in 77 (48.4%). Following docetaxel-based chemotherapy, PSA declined in 118 patients (74.3%), including 87 (54.6%) achieving a PSA decline≥50%, and the median progression-free survival and overall survival (OS) were 2.9 and 23.2 months, respectively. Of several factors examined, univariate analysis identified performance status (PS), significant clinical pain, bone metastasis, schedule of treatment, treatment cycle, and PSA response as significant predictors of OS, of which only PS, treatment cycle, and PSA response appeared to be independently associated with OS on multivariate analysis. The major grade 3-4 toxicities were myelosuppression, including neutropenia, anemia, and thrombocytopenia in 78 (49.1%), 22 (13.8%), and 14 (8.8%), respectively.

CONCLUSIONS

These findings suggest that docetaxel-based chemotherapy is clinically feasible in Japanese men aged≥75 years with mCRPC considering the cancer control as well as safety associated with this therapy.