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

Effect of Chemotherapy on Overall Survival in Contemporary Metastatic Prostate Cancer Patients

Introduction

Randomized clinical trials demonstrated improved overall survival in chemotherapy exposed metastatic prostate cancer patients. However, real-world data validating this effect with large scale epidemiological data sets are scarce and might not agree with trials. We tested this hypothesis.

Materials and Methods

We identified de novo metastatic prostate cancer patients within the Surveillance, Epidemiology, and End Results (SEER) database (2014-2015). Kaplan-Meier plots and Cox regression models tested for overall survival differences between chemotherapy-exposed patients vs chemotherapy-naïve patients. All analyses were repeated in propensity-score matched cohorts. Additionally, landmark analyses were applied to account for potential immortal time bias.

Results

Overall, 4295 de novo metastatic prostate cancer patients were identified. Of those, 905 (21.1%) patients received chemotherapy vs 3390 (78.9%) did not. Median overall survival was not reached at 30 months follow-up. Chemotherapy-exposed patients exhibited significantly better overall survival (61.6 vs 54.3%, multivariable HR:0.82, CI: 0.72-0.96, p=0.01) at 30 months compared to their chemotherapy-naïve counterparts. These findings were confirmed in propensity score matched analyses (multivariable HR: 0.77, CI:0.66-0.90, p<0.001). Results remained unchanged after landmark analyses were applied in propensity score matched population.

Conclusions

In this contemporary real-world population-based cohort, chemotherapy for metastatic prostate cancer patients was associated with better overall survival. However, the magnitude of overall survival benefit was not comparable to phase 3 trials.

Improvement in overall and cancer-specific survival in contemporary, metastatic prostate cancer chemotherapy exposed patients

INTRODUCTION

Over the last decade, multiple clinical trials demonstrated improved survival after chemotherapy for metastatic prostate cancer (mPCa). However, real-world data validating this effect within large-scale epidemiological data sets are scarce. We addressed this void.

MATERIALS AND METHODS

Men with de novo mPCa were identified and systemic chemotherapy status was ascertained within the Surveillance, Epidemiology, and End Results database (2004-2016). Patients were divided between historical (2004-2013) versus contemporary (2014-2016). Chemotherapy rates were plotted over time. Kaplan-Meier plots and Cox regression models with additional multivariable adjustments addressed overall and cancer-specific mortality. All tests were repeated in propensity-matched analyses.

RESULTS

Overall, 19,913 patients had de novo mPCa between 2004 and 2016. Of those, 1838 patients received chemotherapy. Of 1838 chemotherapy-exposed patients, 903 were historical, whereas 905 were contemporary. Chemotherapy rates increased from 5% to 25% over time. Median overall survival was not reached in contemporary patients versus was 24 months in historical patients (hazard ratio [HR]: 0.55, p < 0.001). After propensity score matching and additional multivariable adjustment (age, prostate-specific antigen, GGG, cT-stage, cN-stage, cM-stage, and local treatment) a HR of 0.55 (p < 0.001) was recorded. Analyses were repeated for cancer-specific mortality after adjustment for other cause mortality in competing risks regression models and recorded virtually the same findings before and after propensity score matching (HR: 0.55, p < 0.001).

CONCLUSIONS

In mPCa patients, chemotherapy rates increased over time. A concomitant increase in survival was also recorded.

Prognostic significance of third-line treatment for patients with metastatic castration-resistant prostate cancer: comparative assessments between cabazitaxel and other agents

BACKGROUND

Cabazitaxel has played an important role in the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC); however, several types of sequential therapy against mCRPC have been performed in routine clinical practice. The objective of this study was to investigate the impact of third-line treatment on prognostic outcomes of mCRPC patients.

METHODS

This study retrospectively analyzed the clinical outcomes of 166 patients who received 3 agents following the diagnosis of mCRPC, consisting of 81 sequentially treated with either abiraterone or enzalutamide and then docetaxel, followed by third-line cabazitaxel (group A) and 85 treated with 3 agents, including abiraterone, enzalutamide, and docetaxel (group B).

RESULTS

There were no significant differences in major characteristics at the introduction of the third-line agent between these 2 groups. The proportion of patients with prostate-specific antigen (PSA) reduction > 50% by cabazitaxel in group A was significantly greater than that by either third-line agent in group B. Both PSA progression-free survival (PFS) and overall survival (OS) following third-line therapy in group A were significantly longer than those in group B. Furthermore, OS after the diagnosis of mCRPC in group A was significantly longer than that in group B. Multivariate analysis identified independent predictors of favorable prognostic outcomes after third-line therapy as follows: high-performance status (PS), low PSA level and third-line cabazitaxel for PSA PFS, and high PS, low lactate dehydrogenase level and third-line cabazitaxel for OS.

CONCLUSIONS

The introduction of cabazitaxel as a third-line agent could markedly improve the prognostic outcomes of mCRPC patients.

Sequential Docetaxel in ≥7 Cycles Followed by Cabazitaxel Improves Oncological Outcomes in Patients with Metastatic Castration-Resistant Prostate Cancer

Background. Docetaxel (DOC) was the first regimen that increased the survival and became the standard-of-care in patients with metastatic castration-resistant prostate cancer (mCRPC). However, it is unclear whether switching to second-line chemotherapy or optimal sequencing of cabazitaxel (CBZ) ensures better clinical outcomes. We aimed to evaluate the efficacy of sequential therapy with DOC and CBZ and the effect of the number of prior DOC cycles on oncological outcomes in patients with mCRPC. Methods. We retrospectively included 46 mCRPC patients who received DOC followed by CBZ at quaternary hospitals in Japan between February 2015 and March 2019. Participants received intravenous DOC (40–75 mg/m2) every 3–4 weeks; CBZ (15–25 mg/m2) was administered every 3–4 weeks. Androgen-deprivation therapy and prednisolone 5 mg (twice daily) were administered throughout both regimens. The primary endpoints were overall (OS) and progression-free survival (PFS). The secondary endpoints were the rates of ≥30% and ≥50% reduction in prostate-specific antigen (PSA) levels at chemotherapy initiation. Results. Participants were divided into two groups according to DOC cycles (Groups A and B: ≤6 and ≥7 DOC cycles, respectively). The rates of ≥30% and ≥50% reduction in PSA levels were higher in Group B than in Group A, but there were no significant differences in both groups. Median OS in Groups A and B was 12.7 and 71.0 months, respectively $\left(P<0.001\right)$ ; median PFS in Groups A and B was 3 and 12 months, respectively $\left(P<0.001\right)$ . Conclusions. Administration of ≥7 cycles of DOC followed by CBZ may improve oncological outcomes in patients with mCRPC.

Improved cancer-specific free survival and overall free survival in contemporary metastatic prostate cancer patients: a population-based study

OBJECTIVES

Over the past decade, several systemic agents as docetaxel, cabazitaxel, sipuleucel-T, abiraterone and enzalutamide have improved overall survival (OS) in metastatic prostate cancer (mPCa) patients. However, to date the OS benefit was not demonstrated in population-based analysis.

METHODS

Between 2004 and 2014, 19,047 men with de novo mPCa were identified within the Surveillance Epidemiology and End Results database. Median year of diagnosis resulted in two groups: historical (2004-2008) and contemporary (2009-2014). Due to potentially important differences according to year of diagnosis, we relied on propensity score matching. Propensity-score-matched Kaplan-Meier analyses and Cox regression models (CRMs) tested cancer-specific mortality (CSM) free survival and overall mortality (OM) free survival according to treatment period.

RESULTS

The propensity-score-matched cohort consisted of 8596 patients with mPCa. Of those, 4298 (50.0%) were historical (2004-2008) and 4298 (50.0%) were contemporary (2009-2014). CSM free survival rates and OM free survival rate were 32 versus 36 months (p < 0.0001) and 26 versus 29 months (p < 0.0001) for, respectively, historical and contemporary patients. In multivariable CRMs, patients diagnosed in contemporary years had lower CSM (HR 0.88; CI 0.82-0.93) and OM (HR 0.88; CI 0.84-0.93) risks compared to historical counterpart (all p < 0.0001).

CONCLUSION

This population-based study provides the first evidence of improved CSM free survival and OM free survival in patients with de novo mPCa since the introduction of several systemic agents for CRPC patients.

Predictive Comprehensive Geriatric Assessment in elderly prostate cancer patients: the prospective observational scoop trial results

The Comprehensive Geriatric Assessment (CGA) represents the future of the geriatric oncology to reduce toxicities and treatment-related hospitalization in the elderly. Most patients receiving docetaxel for metastatic castration-resistant prostate cancer are in their seventies or older. We explored the efficacy of the CGA in predicting chemotherapy feasibility and response to docetaxel in a cohort of 24 patients aged at least 70. This was an observational, prospective study involving 24 patients who were 70 years of age or older and about to start chemotherapy with docetaxel for metastatic castration-resistant prostate cancer; we performed a CGA including five domains and divided our patients into 'healthy' and 'frail'; the relations between general condition and (i) early chemotherapy discontinuation and (ii) response to docetaxel were explored. We found a statistically significant relationship between frailty assessed by CGA and early docetaxel discontinuation; we also found an association between frailty and response to chemotherapy, but this did not reach statistical significance. A geriatric assessment before starting chemotherapy may help clinicians to recognize frail patients, and hence to reduce toxicities and early treatment discontinuation. Further analyses are required to simplify the CGA tools and to facilitate its incorporation into routine clinical practice.

Prostate cancer in East Asia: evolving trend over the last decade

Prostate cancer is now becoming an emerging health priority in East Asia. Most of our current knowledge on Prostate cancer has been generated from studies conducted in Western population; however, there is considerable heterogeneity of Prostate cancer between East and West. In this article, we reviewed epidemiologic trends, risk factors, disease characteristics and management of Prostate cancer in East Asian population over the last decade. Growing evidence from East Asia suggests an important role of genetic and environmental risk factors interactions in the carcinogenesis of Prostate cancer. Exposure to westernized diet and life style and improvement in health care in combination contribute substantially to the increasing epidemic in this region. Diagnostic and treatment guidelines in East Asia are largely based on Western knowledge. Although there is a remarkable improvement in the outcome over the last decade, ample evidence suggests an inneglectable difference in diagnostic accuracy, treatment efficacy and adverse events between different populations. The knowledge from western countries should be calibrated in the Asian setting to provide a better race-based treatment approach. In this review, we intend to reveal the evolving trend of Prostate cancer in the last decade, in order to gain evidence to improve Prostate cancer prevention and control in East Asia.

A prospective study examining elder-relevant outcomes in older adults with prostate cancer undergoing treatment with chemotherapy or abiraterone

BACKGROUND

Treatment of metastatic castration-resistant prostate cancer (mCRPC) with chemotherapy improves disease control and survival in fit older men (age 65+) but its impact on function is not clear. We hypothesized that chemotherapy would impair daily function in older men with mCRPC.

METHODS

Men aged 65+ with mCRPC starting chemotherapy or abiraterone were enrolled in this prospective observational pilot study. Daily function was evaluated with the OARS Instrumental Activities of Daily Living (IADL) scale. Three objective measures were used to assess physical function. Patients completed Functional Assessment of Cancer Therapy questionnaires measuring prostate-specific and general quality-of-life (QOL). Vulnerability was evaluated using the Vulnerable Elders Survey (VES-13). Assessments were completed before each cycle of chemotherapy or every 2-3 months for those receiving abiraterone. We compared outcomes pre- and post-treatment and with published minimal clinically important differences.

RESULTS

We evaluated 29 and 7 men on 1st-line and 2nd-line chemotherapy (median 6 and 7 cycles, respectively) and 11 men receiving abiraterone for a median 7 months. IADL scores declined slightly after 1st-line chemotherapy (mean -0.31 points, 95% confidence interval 0.39, -1.02). Physical performance remained stable over time. Both general and prostate-specific QOL improved with 1st-line chemotherapy. For all but one outcome (Timed Chair Stands), vulnerable men had similar changes over time compared to non-vulnerable men. Second-line chemotherapy and abiraterone were generally well-tolerated.

CONCLUSION

IADL function declined slightly whereas physical function remained stable and QOL improved during chemotherapy. Vulnerable and non-vulnerable older men with mCRPC appear to tolerate 1st-line chemotherapy fairly well.

Low-Dose Docetaxel Combined with Dexamethasone Is Feasible for Patients with Castration-Resistant Prostate Cancer

AIM

Docetaxel-based chemotherapy against castration-resistant prostate cancer (CRPC) has recently been shown to be effective and tolerable. The objective of this study was to retrospectively evaluate the efficacy and toxicity of low-dose docetaxel in combination with dexamethasone.

METHODS

Thirty-seven CRPC patients were administered a treatment regimen consisting of 50 mg/m2 docetaxel once every 3-4 weeks and 1 mg dexamethasone daily at our institution, between November 2004 and April 2014.

RESULTS

Twenty-four patients (65%) had a decrease in serum prostate-specific antigen (PSA) >50%. The median overall survival (OS) and PSA progression-free survival were 26.2 and 10.0 months, respectively. Ten of 12 patients (83%) taking analgesic agents reduced their intake because of decreased pain levels. Grade 3 febrile neutropenia occurred in 2 patients (5%). Nonhematological toxicities were less frequent but sometimes severe. Treatment-related death occurred in 2 octogenarian patients, 1 due to gastric bleeding and the other due to infective endocarditis.

CONCLUSION

Low-dose docetaxel in combination with dexamethasone is feasible in Japanese CRPC patients. Hematological toxicity is less than that seen with standard docetaxel therapy, but it is necessary to monitor patients for severe nonhematological toxicities, particularly very elderly patients.

Docetaxel in very elderly men with metastatic castration-resistant prostate cancer

PURPOSE

To evaluate the use of docetaxel in very elderly men with metastatic castration-resistant prostate cancer (mCRPC) treated in routine clinical care.

METHODS

A retrospective case series of men with mCRPC aged ≥80 years and treated with docetaxel between July 2006 and June 2012 at three community hospitals in Melbourne, Australia.

RESULTS

Twenty patients were identified, with a median age of 83 years (range 80-93 years). Aside from one patient treated weekly, all patients were treated with a 3-weekly regimen of docetaxel with a median of six cycles (range 1-10 cycles) delivered. Eight patients (40%) had an initial dose reduction and 11 patients (55%) had subsequent dose delays or reductions. Eight patients (40%) completed planned treatment. Grade 3/4 hematologic toxicity was observed in nine patients (45%), and five patients (25%) were admitted to hospital with chemotherapy-related complications. Prostate-specific antigen (PSA) response was assessable for 16 patients, of whom nine (56%) had a PSA response of ≥50% and one (6%) had a PSA-complete response. The median overall survival in this cohort was 13.4 months.

CONCLUSIONS

Very elderly patients (80 + years) with mCRPC are infrequently included in clinical trials, yet the use of chemotherapy in this population is likely to increase. Our series demonstrates significant response rates to docetaxel chemotherapy, but that a substantial number of patients had treatment-related complications. This highlights the need for careful patient selection and optimization of chemotherapy dosing.

Repression of NR4A1 by a chromatin modifier promotes docetaxel resistance in PC-3 human prostate cancer cells

Epigenetic silencing mechanisms play an important role in chemoresistance of human cancer. Here we report the upregulated expression of metastasis-associated protein 1 (MTA1), a component of the nucleosome remodeling deacetylation (NuRD) complex, in chemoresistant prostate cancer (PCa). MTA1 knockdown in PC-3 cells inhibited cell proliferation and enhanced docetaxel (DTX)-induced cell death. Conversely, overexpression of MTA1 promotes DTX chemoresistance in PC-3 cells. MTA1 acted as a potent corepressor of the nuclear receptor NR4A1 transcription by interacting with histone deacetylase 2 (HDAC2). These findings suggest that MTA1 may serve as a novel DTX-resistance promoter in PC-3 cells.

The effectiveness of the TAX 327 nomogram in predicting overall survival in Chinese patients with metastatic castration-resistant prostate cancer

Based on the results of TAX 327, a nomogram was developed to predict the overall survival of metastatic castration-resistant prostate cancer (mCRPC) after first-line chemotherapy. The nomogram, however, has not been validated in an independent dataset, especially in a series out of clinical trials. Thus, the objective of the current study was to validate the TAX 327 nomogram in a community setting in China. A total of 146 patients with mCRPC who received first-line chemotherapy (docetaxel or mitoxantrone) were identified. Because clinical trials are limited in mainland China, those patients did not receive investigational treatment after the failure of first-line chemotherapy. The predicted overall survival rate was calculated from the TAX 327 nomogram. The validity of the model was assessed with discrimination, calibration and decision curve analysis. The median survival of the cohort was 21 months (docetaxel) and 19 months (mitoxantrone) at last follow-up. The predictive c-index of the TAX 327 nomogram was 0.66 (95% CI: 0.54-0.70). The calibration plot demonstrated that the 2-year survival rate was underestimated by the nomogram. Decision curve analysis showed a net benefit of the nomogram at a threshold probability greater than 30%. In conclusion, the present validation study did not confirm the predictive value of the TAX 327 nomogram in a contemporary community series of men in China, and further studies with a large sample size to develop or validate nomograms for predicting survival and selecting therapies in advanced prostate cancer are necessary.