External validation and newly development of a nomogram to predict overall survival of abiraterone-treated, castration-resistant patients with metastatic prostate cancer

Predictive Models for Assessing Patients' Response to Treatment in Metastatic Prostate Cancer: A Systematic Review

Background and objective

The treatment landscape of metastatic prostate cancer (mPCa) has evolved significantly over the past two decades. Despite this, the optimal therapy for patients with mPCa has not been determined. This systematic review identifies available predictive models that assess mPCa patients' response to treatment.

Methods

We critically reviewed MEDLINE and CENTRAL in December 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. Only quantitative studies in English were included with no time restrictions. The quality of the included studies was assessed using the PROBAST tool. Data were extracted following the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews criteria.

Key findings and limitations

The search identified 616 citations, of which 15 studies were included in our review. Nine of the included studies were validated internally or externally. Only one study had a low risk of bias and a low risk concerning applicability. Many studies failed to detail model performance adequately, resulting in a high risk of bias. Where reported, the models indicated good or excellent performance.

Conclusions and clinical implications

Most of the identified predictive models require additional evaluation and validation in properly designed studies before these can be implemented in clinical practice to assist with treatment decision-making for men with mPCa.

Patient summary

In this review, we evaluate studies that predict which treatments will work best for which metastatic prostate cancer patients. We found that existing studies need further improvement before these can be used by health care professionals.

Development and validation of a survival nomogram and calculator for male patients with metastatic castration-resistant prostate cancer treated with abiraterone acetate and/or enzalutamide

BACKGROUND

Despite the widespread availability of medication choices for metastatic castration-resistant prostate cancer (mCRPC), biomarkers to predict the efficacy of each mCRPC treatment have not yet been established. This study developed a prognostic nomogram and a calculator to predict the prognosis of patients with mCRPC who received abiraterone acetate (ABI) and/or enzalutamide (ENZ).

METHODS

In total, 568 patients with mCRPC who underwent ABI and/or ENZ between 2012 and 2017 were enrolled. A prognostic nomogram based on the risk factors was developed using the Cox proportional hazards regression model and clinically important factors. The discriminatory ability of the nomogram was assessed according to the concordance index (C-index). A 5-fold cross-validation was repeated 2000 times to estimate the C-index, and the means of the estimated C-index for the training and validation sets were determined. A calculator based on this nomogram was then developed.

RESULTS

The median overall survival (OS) was 24.7 months. Multivariate analysis showed that the time to CRPC, pre-chemotherapy, baseline prostate-specific antigen, baseline alkaline phosphatase, and baseline lactate dehydrogenase levels were independent risk factors for OS (hazard ratio [HR]: 0.521, 1.681, 1.439, 1.827, and 12.123, p = 0.001, 0.001,  < 0.001, 0.019, and  < 0.001, respectively). The C-index was 0.72 in the training cohort and 0.71 in the validation cohort.

CONCLUSIONS

We developed a nomogram and calculator to predict OS in Japanese patients with mCRPC who received ABI and/or ENZ. Reproducible prognostic prediction calculators for mCRPC will facilitate greater accessibility for clinical use.

Factors influencing survival in metastatic castration resistant prostate cancer therapy

INTRODUCTION

The number of patients with metastatic castration resistant prostate cancer (mCRPC) is expecting to increase due to the long-life expectancy of those with advanced disease who are also more commonly diagnosed today because of stage migration. Several compounds are available for treating these patients.

AREAS COVERED

We reviewed currently available treatments for mCRPC, their mechanism of action and resistance and we explored possible predictors of treatment success useful to predict survival in mCRPC patients.

EXPERT OPINION

A combination of molecular, clinical, pathological, and imaging features is necessary to correctly estimate patients' risk of death. The combination of these biomarkers may allow clinicians to tailor treatments based on cancer history and patients' features. The search of predictive biomarkers remains an unmet medical need for most patients with mCRPC.

Prognostic significance of risk stratification in CHAARTED and LATITUDE studies among Japanese men with castration-resistant prostate cancer

Background

The CHAARTED and LATITUDE trials demonstrated a survival benefit of docetaxel and abiraterone for hormone-sensitive prostate cancer. In this study, we examined the impact of the risk stratification criteria used in the CHAARTED and LATITUDE trials on the prognosis of castration-resistant prostate cancer (CRPC). We also tested whether these risk stratification criteria could help in selecting effective initial treatment for CRPC.

Method

Japanese patients with CRPC who were treated with docetaxel or androgen receptor pathway inhibitors such as abiraterone acetate or enzalutamide between 2014 and 2018 were included in this study. Clinicopathological factors, progression-free survival, and overall survival were investigated.

Results

Of 215 patients, 110 men (51.2%) and 93 men (43.3%) were grouped as high volume by CHAARTED criteria and high risk by LATITUDE criteria, respectively. Median progression-free survival was 10.3/4.5 months (P < 0.0001) for low/high volume (CHAARTED criteria) and 9.9/4.8 months (P = 0.0032) for low/high risk (LATITUDE criteria). The median overall survival was 44.8/17.4 months (P < 0.0001) for low/high volume (CHAARTED criteria) and 37.4/17.4 months (P = 0.0011) for low/high risk (LATITUDE criteria). The prognostic impact of CHAARTED and LATITUDE criteria was comparable between androgen receptor pathway inhibitors and docetaxel as first-line treatment for CRPC.

Conclusion

The CHAARTED and LATITUDE criteria were prognostic, but not useful to discriminate the therapeutic outcome between androgen receptor pathway inhibitors and docetaxel for CRPC.

Clinical outcome of surgical management for symptomatic metastatic spinal cord compression from prostate cancer

BACKGROUND

Metastatic spinal cord compression (MSCC) from prostate cancer (PC) influences not only patients' prognosis but also their quality of life. However, little is known about the clinical outcome of surgery for MSCC from PC. We evaluated both the oncological and functional outcomes of decompression and reconstruction surgery for patients with symptomatic MSCC from PC.

METHODS

We assessed 19 patients who underwent decompression and reconstruction surgery for symptomatic MSCC from PC. Of these 19 patients, 8 had metastatic hormone-naïve PC (mHNPC) and 11 had metastatic castration-resistant PC (mCRPC).

RESULTS

The median age of the patients with mHNPC and mCRPC was 72 and 65 years, respectively. The median prostate-specific antigen level at the time of diagnosis of MSCC in patients with mHNPC and mCRPC was 910 and 67 ng/mL, respectively. Although two of eight patients (25.0%) with mHNPC were ambulatory preoperatively, six patients (75.0%) were ambulatory postoperatively. Among 11 patients with mCRPC, only 3 (27.3%) were ambulatory preoperatively, while 6 (54.5%) were ambulatory postoperatively. The median postoperative overall survival among patients with mHNPC and mCRPC were not reached and 8 months, respectively.

CONCLUSIONS

Decompression and reconstruction surgery for symptomatic MSCC from PC might contribute to a favorable functional outcome among men with mHNPC and mCRPC. However, its role in improving the oncological outcome remains unclear. The treatment strategy should be chosen by shared decision-making among patients, urologists, radiation oncologists, and orthopedic surgeons.

Development and validation of prognostic nomograms for patients with metastatic prostate cancer

OBJECTIVE

This study aimed to develop and validate nomograms to predict overall survival (OS) and cancer-specific survival (CSS) in patients with prostate cancer.

METHODS

Clinical data of patients with mPCa between 2010 and 2014 were retrieved retrospectively, and randomized into training (2/3) and validation sets (1/3). Nomograms were built with potential risk factors based on COX regression analysis. Accuracy was validated using the discrimination and calibration curve for the training and validation groups, respectively.

RESULTS

6659 mPCa patients were collected and enrolled, including 4440 in the training set and 2219 in the validation set. Multivariate analysis showed that age, marital status, PSA, biopsy Gleason score, T stage, and bone metastasis were independent risk factors for both OS and CSS. The concordance index (C-index) of OS was 0.735 (95% CI 0.722-0.748) for the internal validation and 0.735 (95% CI 0.717-0.753) for the external validation. For CSS, it was 0.734 (95% CI 0.721-0.747) and 0.742 (95% CI 0.723-0.761), respectively. The nomograms for predicting OS and CSS displayed better discrimination power in both training and validation sets. Moreover, a favorable consistency between the predicted and actual survival probabilities was demonstrated using calibration curves.

CONCLUSIONS

The nomograms showed good performances for predicting OS and CSS in patients with prostate cancer. It might be a convenient individualized predictive tool for prognosis in clinical practice.

Anemia is associated with poor outcomes of metastatic castration-resistant prostate cancer, a systematic review and meta-analysis

Androgen deprivation therapy (ADT) was an important management for metastatic prostate cancer. However, patients would finally progress to the metastatic castration-resistant prostate cancer (mCRPC) and lose sensitivity to ADT. In addition to lower testosterone level, ADT could cause anemia, which might impair the chemotherapy efficiency and worsen the outcomes of cancer patients. However, inconsistent results were found between anemia and mCRPC prognosis. Our study was the first systematic review to evaluate the influence of anemia in mCRPC prognosis. Thirteen studies with 6,484 samples were involved in this meta-analysis. We found anemia would worsen the Overall survival (OS) of mCRPC patients in both prognostic designed studies (HR = 1.55, 95% CI = 1.24-1.94) and retrospective designed studies (HR = 1.82, 95% CI = 1.52-2.18). Prognostic analyses also demonstrated that anemia associated with poor Progression free survival (PFS) (HR = 1.47, 95% CI = 1.22-1.75). In conclusion, we found that anemia was significantly associated with poor OS and PFS of mCRPC patients. Larger RCTs are needed for future study, especially for the evaluation of treatment value for anti-anemia in mCRPC.

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.