Population-Based Study of Docetaxel or Abiraterone Effectiveness and Predictive Markers of Progression Free Survival in Metastatic Castration-Sensitive Prostate Cancer

Comparison of Short-Term Outcomes and Safety Profiles between Androgen Deprivation Therapy+Abiraterone/Prednisone and Androgen Deprivation Therapy+Docetaxel in Patients with De Novo Metastatic Hormone-Sensitive Prostate Cancer

PURPOSE

This study aimed to compare the short-term outcomes and safety profiles of androgen-deprivation therapy (ADT)+abiraterone/prednisone with those of ADT+docetaxel in patients with de novo metastatic hormone-sensitive prostate cancer (mHSPC).

MATERIALS AND METHODS

A web-based database system was established to collect prospective cohort data for patients with mHSPC in Korea. From May 2019 to November 2022, 928 patients with mHSPC from 15 institutions were enrolled. Among these patients, data from 122 patients who received ADT+abiraterone/prednisone or ADT+docetaxel as the primary systemic treatment for mHSPC were collected. The patients were divided into two groups: ADT+abiraterone/prednisone group (n=102) and ADT+docetaxel group (n=20). We compared the demographic characteristics, medical histories, baseline cancer status, initial laboratory tests, metastatic burden, oncological outcomes for mHSPC, progression after mHSPC treatment, adverse effects, follow-up, and survival data between the two groups.

RESULTS

No significant differences in the demographic characteristics, medical histories, metastatic burden, and baseline cancer status were observed between the two groups. The ADT+abiraterone/prednisone group had a lower prostate-specific antigen (PSA) progression rate (7.8% vs. 30.0%; p=0.011) and lower systemic treatment discontinuation rate (22.5% vs. 45.0%; p=0.037). No significant differences in adverse effects, oncological outcomes, and total follow-up period were observed between the two groups.

CONCLUSIONS

ADT+abiraterone/prednisone had lower PSA progression and systemic treatment discontinuation rates than ADT+docetaxel. In conclusion, further studies involving larger, double-blinded randomized trials with extended follow-up periods are necessary.

A territory-wide real-world efficacy and toxicity analysis of abiraterone acetate versus docetaxel in 574 Asian patients with metastatic hormone-sensitive prostate cancer

INTRODUCTION

Abiraterone acetate (ABI) or docetaxel (DOC), in addition to androgen-deprivation therapy (ADT), are current treatment options for metastatic hormone-sensitive prostate cancer (mHSPC). No randomized head-to-head trial has compared these 2 mHSPC treatments, and real-world data regarding their outcomes in Asian patients are lacking.

PATIENTS AND METHODS

The medical records of mHSPC patients who began upfront ABI or DOC treatment in addition to ADT at seven public oncology centers in Hong Kong between 2015 and 2021 were reviewed. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), prostate-specific antigen (PSA) response, and toxicities. Kaplan-Meier and multivariate Cox regression analyses were performed.

RESULTS

A total of 574 patients were included, of whom 419 received DOC and 155 received ABI. The median follow-up duration was 22.4 (DOC group: 23.8; ABI group: 17.3) months. The ABI group demonstrated significantly better PFS than the DOC group (not reached vs. 15.1 months: hazard ratio = 0.37; 95% confidence interval = 0.28-0.50; P < .001). No significant OS difference was observed (P = .58). Failure to achieve a ≥ 90% decline in PSA level at 3 months and failure to achieve an undetectable PSA nadir were each associated with unfavorable PFS and OS. Patients who received DOC had a higher rate of febrile neutropenia, whereas those who received ABI had higher rates of grade ≥ 3 hypokalemia and elevated alanine transaminase. Treatment discontinuation due to toxicities was more common in the DOC (3.6%) than the ABI (0.6%) group.

CONCLUSION

In Asian mHSPC patients, upfront ABI + ADT was associated with better PFS than DOC + ADT, with no significant OS difference. PSA kinetics may help stratify the prognosis for treatment intensification. Toxicity profiles were different, with a higher rate of toxicity-related treatment discontinuation in the DOC group.

Real-world outcomes and risk stratification in patients with metastatic castration-sensitive prostate cancer treated with upfront abiraterone acetate and docetaxel

PURPOSE

We assessed clinical outcomes in patients with metastatic castration-sensitive prostate cancer (mCSPC) treated with two upfront therapies.

METHODS

The medical records of 301 patients with mCSPC treated with androgen deprivation therapy plus upfront abiraterone acetate (ABI) or docetaxel (DOC) between 2014 and 2021 were retrospectively reviewed. Propensity score matching (PSM) was performed to compare survival outcomes. Subgroup analyses of risk factors for second progression were conducted.

RESULTS

A total of 95 patients received upfront DOC, whereas 206 received upfront ABI. After PSM, the ABI group had a significantly better castration-resistant prostate cancer (CRPC)-free survival than the DOC group [hazard ratio (HR), 0.53; 95% confidence interval (CI), 0.34-0.82]. Second progression-free survival (PFS2) tended to be longer in the ABI group than in the DOC group, but the difference was not statistically significant (HR, 0.64; 95% CI, 0.33-1.22). No significant difference in overall survival (OS) was found between the two groups (HR, 0.92; 95% CI, 0.42-2.03). In the subgroup analysis, upfront ABI had significantly favorable PFS2 in patients aged ≥ 75 years compared with upfront DOC (p = 0.038). Four risk factors for second progression (primary Gleason 5, liver metastasis, high serum alkaline phosphatase level, and high serum lactate dehydrogenase level) successfully stratified patients into three risk groups.

CONCLUSIONS

Upfront ABI provided better CRPC-free survival than upfront DOC; however, no significant differences in PFS2 or OS were observed between the two groups. Personalized management based on prognostic risk factors may benefit patients with mCSPC treated with upfront intensified therapies.

Real-world survival outcomes of adding docetaxel or abiraterone in patients with high-volume metastatic castration-sensitive prostate cancer: historically controlled, propensity score matched comparison with androgen deprivation therapy

PURPOSE

This study investigated the impact of treatment intensification with upfront docetaxel (DOC) or abiraterone (ABI) plus prednisolone on survival outcomes in patients with metastatic castration-sensitive prostate cancer (mCSPC) by comparing it with androgen deprivation therapy (ADT) monotherapy or combined androgen blockade (CAB) using propensity score matching (PSM).

METHODS

Outcomes from 278 CHAARTED high-volume patients receiving upfront DOC (92 patients) or upfront ABI (186 patients) were compared to those from 354 patients receiving ADT or CAB. PSM was conducted to assess castration-resistant prostate cancer-free survival (CRPCFS) and overall survival (OS).

RESULTS

After PSM, patient distributions between the three groups were well balanced. After 1:1 PSM, patients receiving upfront ABI had significantly better CRPCFS than those receiving ADT/CAB or upfront DOC [hazard ratio (HR) 0.39; 95% CI 0.27-0.56 vs. HR 0.50; 95% CI 0.30-0.82, respectively]. No significant difference in CRPCFS was observed between the upfront DOC and ADT/CAB groups (HR 0.75; 95% CI 0.50-1.12). Patients receiving upfront DOC and upfront ABI had significantly better OS than those receiving ADT/CAB (HR 0.54; 95% CI 0.0.30-0.98 vs. HR 0.49; 95% CI 0.29-0.84, respectively). However, no significant difference in OS was observed between upfront ABI and upfront DOC (hazard ratio 0.84; 95% CI 0.34-2.06).

CONCLUSION

The comparison of real-world retrospective cohorts showed that treatment intensification with upfront DOC or upfront ABI promoted better OS compared to ADT alone or CAB in patients with high-volume mCSPC after PSM. However, no difference in OS was observed between upfront DOC and upfront ABI.

Presence of CD133-positive circulating tumor cells predicts worse progression-free survival in patients with metastatic castration-sensitive prostate cancer

Objective

To investigate the clinical significance of the expression of the stemness marker CD133 in circulating tumor cells of newly diagnosed metastatic castration‐sensitive prostate cancer patients.

Methods

For this study, 104 metastatic castration‐sensitive prostate cancer patients treated at the Fudan University Shanghai Cancer Center from September 2015 to February 2017 were considered. After enrollment, the patients received androgen deprivation therapy (bicalutamide + goserelin). Circulating tumor cells were isolated and identified using the CanPatrol system, which can identify not only traditional epithelial markers but also mesenchymal markers in cells that have undergone epithelial mesenchymal transition. CD133 was used to characterize the circulating tumor cells. The primary endpoint of this research was to evaluate progression to castration resistance.

Results

Among the 104 patients enrolled, 89 patients were circulating tumor cell positive at baseline, and the median circulating tumor cell count was four. The median follow‐up was 24 months, and at the end of follow‐up, the proportion of patients who progressed to castration‐resistant prostate cancer in the CTC+CD133+ group was 93.3%, which was significantly higher than that of the circulating tumor cell negative group (73.3%) and the CTC+CD133− group (75.0%), with P = 0.043. After follow‐up, progression‐free survival for CTC+CD133+, CTC+CD133−, and circulating tumor cell patients was 10.0, 13.0, and 14.0 months, respectively, with P = 0.022. Univariate and multivariate analyses also confirmed that the characterization of circulating tumor cells using CD133 can independently predict progression‐free survival in metastatic castration‐sensitive prostate cancer patients after receiving androgen deprivation therapy (P = 0.042; hazard ratio 1.396).

Conclusion

Baseline CTC+CD133+ was a poor independent prognostic factor for metastatic castration‐sensitive prostate cancer patients to progress to castration‐resistant prostate cancer after receiving androgen deprivation therapy.

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.