Serum testosterone level as possible predictive marker in androgen receptor axis-targeting agents and taxane chemotherapies for castration-resistant prostate cancer

Co-expression of Twist and Snai1: predictor of poor prognosis and biomarker of treatment resistance in untreated prostate cancer

BACKGROUND

Prostate cancer (PCa) remains one of the most complex tumors in men. The assessment of gene expression is expected to have a profound impact on cancer diagnosis, prognosis, and treatment decisions. The aim of this study was to determine the utility of the epithelial-mesenchymal transition (EMT) transcription factors Twist and Snai1 in the treatment of naïve prostate cancer.

METHODS AND RESULTS

We analyzed formalin-fixed paraffin-embedded (FFPE) prostate tissues from 108 PCa patients and 20 control biopsies using real-time quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and 2-ΔΔCt methods for Twist and Snail gene expression. The expression of Twist and Snai1 mRNA was significantly overexpressed in primary tissues of PCa patients compared with controls using ROC curve. Statistical analysis showed that the mRNAs of these two genes expression Snai1 and Twist were positively correlated with tumor development and prognostic parameters as Gleason score (p < 0.001; r = 0.707) and (p < 0.001; r = 0.627) respectively. The results of Kaplan-Meier analysis showed that mRNA expression of Snai1 and Twist genes expression were significant predictors of poor overall survival (OS) (Log rank p < 0.001) and progression-free survival (PFS) of patients (Log rank p < 0.001). Furthermore, our results showed that the expression of Snai1 and Twist genes expression in primary tissues of PCa patients could predict resistance to androgen deprivation therapy (p < 0.001) and resistance to the acidic drugs abiraterone or enzalutamide (p < 0.001). However, these two transcription factors failed to predict taxanes resistance at the time of diagnosis (p > 0.05).

CONCLUSION

These results suggest that Snai1 and Twist are overexpressed during the onset and progression of PCa malignancies and may be theranostic markers of resistance to ADT, abiraterone, or enzalutamide therapy.

Prognostic significance of serum testosterone level in patients with castration-resistant prostate cancer treated with cabazitaxel

BACKGROUND

Serum testosterone level is a potential prognostic marker for castration-resistant prostate cancer. However, its role as a prognostic marker in cabazitaxel chemotherapy remains unclear. This study aimed to elucidate the clinical significance of serum testosterone levels before cabazitaxel chemotherapy.

METHODS

This single-institution, retrospective study included 47 patients with metastatic castration-resistant prostate cancer (mCRPC) who received cabazitaxel therapy. Serum testosterone levels were measured before the initiation of cabazitaxel therapy.

RESULTS

Progression-free survival and overall survival (OS) were not significantly different between patients with high and low serum testosterone levels. Analysis of patients aged <70 years revealed that those with high serum testosterone levels (total testosterone level > 0.055 ng/mL) had significantly longer OS than those with low serum testosterone levels (total testosterone level < 0.055 ng/mL, p = 0.012). Multivariate analysis revealed that low serum testosterone levels (hazard ratio [HR] = 11.874, 95% confidence interval [CI] 2.076-67.953, p = 0.005) and high prostate-specific antigen levels (HR = 18.051, 95% CI 2.462-132.347, p = 0.004) in the pretreatment phase were independent prognostic factors for OS in patients receiving cabazitaxel therapy.

CONCLUSIONS

Serum testosterone level may be a prognostic marker for cabazitaxel therapy in patients with mCRPC who are younger than 70 years, and high serum testosterone levels may lead to longer survival.

Genomic and Phenotypic Biomarkers for Precision Medicine Guidance in Advanced Prostate Cancer

OPINION STATEMENT

Prostate cancer (PCa) is the second most diagnosed malignant neoplasm and is one of the leading causes of cancer-related death in men worldwide. Despite significant advances in screening and treatment of PCa, given the heterogeneity of this disease, optimal personalized therapeutic strategies remain limited. However, emerging predictive and prognostic biomarkers based on individual patient profiles in combination with computer-assisted diagnostics have the potential to guide precision medicine, where patients may benefit from therapeutic approaches optimally suited to their disease. Also, the integration of genotypic and phenotypic diagnostic methods is supporting better informed treatment decisions. Focusing on advanced PCa, this review discusses polygenic risk scores for screening of PCa and common genomic aberrations in androgen receptor (AR), PTEN-PI3K-AKT, and DNA damage response (DDR) pathways, considering clinical implications for diagnosis, prognosis, and treatment prediction. Furthermore, we evaluate liquid biopsy, protein biomarkers such as serum testosterone levels, SLFN11 expression, total alkaline phosphatase (tALP), neutrophil-to-lymphocyte ratio (NLR), tissue biopsy, and advanced imaging tools, summarizing current phenotypic biomarkers and envisaging more effective utilization of diagnostic and prognostic biomarkers in advanced PCa. We conclude that prognostic and treatment predictive biomarker discovery can improve the management of patients, especially in metastatic stages of advanced PCa. This will result in decreased mortality and enhanced quality of life and help design a personalized treatment regimen.

A prospective study of the relationship between CRPC patient's quality of life after enzalutamide and serum testosterone levels measured via LC-MS/MS

BACKGROUND

Enzalutamide (ENZ) is used in the treatment of patients with castration-resistant prostate cancer (CRPC). The quality of life (QoL) of CRPC patients during ENZ treatment is very important, but predictive markers of QoL have not been identified. We investigated the relationship between the serum testosterone (T) level before ENZ treatment and QoL changes in CRPC patients.

PATIENTS AND METHODS

This prospective study was conducted between 2014 and 2018 at Gunma University Hospital and related facilities. We analyzed 95 patients in whom QoL could be evaluated using the Functional Assessment of Cancer Therapy-Prostate (FACT-P) questionnaire at baseline, and after 4 and 12 weeks of ENZ treatment. Serum T levels were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

The study population of 95 patients had a median age of 72 years and median prostate-specific antigen level of 21.6 ng/mL. The median overall survival from the commencement of ENZ treatment was 26.8 months. The median serum T level before ENZ treatment was 50.0 pg/mL. The mean total FACT-P scores at baseline, and after 4 and 12 weeks of ENZ treatment, were 95.8, 91.7, and 90.1, respectively. Differences in FACT-P scores between the high T level (High-T) group and low T level (Low-T) group (distinguished based on median split of the T level) were examined. The mean FACT-P scores were significantly higher in the High-T than Low-T group after both 4 and 12 weeks of ENZ treatment (98.5 vs. 84.6 and 96.4 vs. 82.2, respectively, both p < 0.05). The mean FACT-P score was significantly lower in the Low-T group after 12 weeks than before ENZ treatment (p < 0.05).

CONCLUSION

The serum T level before treatment may be useful for predicting QoL changes after ENZ treatment in CRPC patients.

The presence of lymph node metastases and time to castration resistance predict the therapeutic effect of enzalutamide for castration-resistant prostate cancer

BACKGROUND

Enzalutamide is effective against castration-resistant prostate cancer (CRPC). However, it is unclear which patients would benefit more from enzalutamide treatment. Here, we analyzed patients who received enzalutamide as first-line therapy for CRPC and evaluated the factors that predict treatment response and prognosis.

METHODS

We retrospectively analyzed 101 patients treated with enzalutamide for CRPC at our institution. As primary endpoints we regarded the prostate-specific antigen (PSA) response rate and PSA-progression-free survival (PSA-PFS) from the start of enzalutamide treatment. Laboratory and imaging data were analyzed to predict treatment efficacy.

RESULTS

PSA reductions of ≥ 50% and ≥ 90% were observed in 78 (77%) and 47 (47%) patients, respectively, compared with the baseline. During the follow-up period, 67 (66%) patients showed PSA progression, with a median PSA-PFS of 11 months. Moreover, 31 patients (31%) died, with a median overall survival of 64 months. On multivariate analysis, lymph node metastases at the start of enzalutamide treatment [odds ratio (OR) 0.0575, 95% confidence interval (CI) 0.0105-0.316, p = 0.0010] and time to CRPC (OR 0.177, 95% CI 0.0428-0.731, p = 0.0167] were associated with ≥ 90% PSA response. Lymph node metastases (hazard ratio [HR] 3.00, 95% CI 1.48-6.09, p = 0.0023) and time to CRPC (HR 1.84, 95% CI 1.02-3.30, p = 0.0419) were also predictors of PSA-PFS on a multivariate model.

CONCLUSIONS

Time to CRPC and lymph node metastasis were predictors of the PSA response rate and PSA-PFS.

Steroidogenesis in castration-resistant prostate cancer

Castration resistance is in part attributable to aberrant activation of androgen receptor (AR) signaling by the intracrine activation of androgen precursors derived from adrenal glands. To overcome this, novel AR pathway inhibitors (ARPIs) that suppress androgen synthesis by CYP17 inhibition or AR activation by antiandrogen effects have been developed. However, primary or acquired resistance to these ARPIs occurs; in turn attributable, at least in part, to the maintained androgen milieu despite intensive suppression of AR signaling similar to castration resistance. In addition to the classical pathway to produce potent androgens such as testosterone and dihydrotestosterone, the alternative pathway and the backdoor pathway which bypasses testosterone to produce dihydrotestosterone have been shown to play a role in intratumor steroidogenesis. Furthermore, the 11β-hydroxyandrostenedione pathway to produce the potent oxygenated androgens 11-ketotestosterone and 11-ketodihydrotestosterone has been suggested to be functional in prostate cancer. These steroidogenesis pathways produce potent androgens that promote tumor resistance to endocrine therapy including novel ARPIs. Here, we overview the current evidence on the pathological androgen milieu by altered metabolism and transport in prostate cancer, leading to resistance to endocrine therapy.

Testosterone analysis in castrated prostate cancer patients: suitability of the castration cut-off and analytical accuracy of the present-day clinical immunoassays

OBJECTIVES

Testosterone testing is relevant for evaluating castration adequacy and diagnosis of castration-resistant prostate cancer (PCa). However, the recommended testosterone cut-off of 1.7 nmol/L (50 ng/dL) to define adequate castration is based on consensus and not validated for the automated immunoassays (AIA) used in today's medical laboratories. Furthermore, appropriate population intervals have not been determined by a state-of-the-art assay. We investigated the analytical suitability of this cut-off and the accuracy of the present-day AIAs for testosterone analysis in castrated PCa patients.

METHODS

Leftover serum from 120 PCa patients castrated with luteinizing hormone-releasing hormone agonists was analysed for testosterone by five methods: Architect i2000 (Abbott), Access (Beckman), Cobas 6000 (Roche), Atellica (Siemens), LC-MS/MS. For all assays, the castration 95th, 97.5th and 99th percentile upper limits were determined. Furthermore, Passing-Bablok regression, mean bias and Spearman's correlation coefficients were compared to the LC-MS/MS method and total error based on biological variation.

RESULTS

All castration upper limits, ranging from 0.472 nmol/L (LC-MS/MS) to 1.25 nmol/L (Access) (95% percentile), were significantly lower than the current castration cut-off (1.7 nmol/L). Slopes of Passing-Bablok regressions comparing the AIA with the LC-MS/MS method ranged from 1.4 (Cobas and Atellica) to 3.8 (Access). The Architect showed the highest correlation with LC-MS/MS (ρ=0.58). All AIA failed to meet the desirable total error criterion.

CONCLUSIONS

These results suggest that a lower general testosterone castration cut-off may be more appropriate in evaluating the adequacy of castration in PCa and that present-day AIA lack analytical accuracy to quantify testosterone levels in castrated PCa.

Emerging Biomarker-Guided Therapies in Prostate Cancer

Prostate cancer remains one of the leading causes of cancer death in men worldwide. In the past decade, several new treatments for advanced prostate cancer have been approved. With a wide variety of available drugs, including cytotoxic agents, androgen receptor axis-targeted therapies, and alpha-emitting radiation therapy, identifying their optimal sequencing remains a challenge. Progress in the understanding of the biology of prostate cancer has provided an opportunity for a more refined and personalized treatment selection process. With the advancement of molecular sequencing techniques, genomic precision through the identification of potential treatment targets and predictive biomarkers has been rapidly evolving. In this review, we discussed biomarker-driven treatments for advanced prostate cancer. First, we presented predictive biomarkers for established, global standard treatments for advanced diseases, such as chemotherapy and androgen receptor axis-targeted agents. We also discussed targeted agents with recent approval for special populations, such as poly ADP ribose polymerase (PARP) inhibitors in patients with metastatic castrate-resistant prostate cancer with homologous recombination repair-deficient tumors, pembrolizumab in patients with high levels of microsatellite instability or high tumor mutational burden, and prostate-specific membrane antigen (PSMA) directed radioligand theragnostic treatment for PSMA expressing tumors. Additionally, we discussed evolving treatments, such as cancer vaccines, chimeric antigen receptor T-cells (CAR-T), Bispecific T-cell engagers (BiTEs), other targeted agents such as AKT inhibitors, and various combination treatments. In summary, advances in molecular genetics have begun to propel personalized medicine forward in the management of advanced prostate cancer, allowing for a more precise, biomarker-driven treatment selection with the goal of improving overall efficacy.

Biomarkers for Treatment Response in Advanced Prostate Cancer

Simple Summary

Prostate cancer is a leading cause of cancer-related death among males. Many treatments are available to manage the disease, but despite this, ultimately advanced prostate cancer is incurable and fatal. In order to improve survival and minimize side effects from these various treatments, the treatments need to be given in an optimal sequence or combination. This optimal use of therapies must be individualized, and biomarkers can be used for these decisions. Biomarkers can be useful in predicting whether a patient will respond to a treatment option and may help avoid use of therapies that are not expected to be effective. Many biomarkers are already in clinical use while many others are currently being investigated and may become part of clinical practice in future. In this review, we discuss both established and novel biomarkers with a role in management of advanced prostate cancer.

Abstract

Multiple treatment options with different mechanisms of action are currently available for the management of metastatic prostate cancer. However, the optimal use of these therapies—specifically, the sequencing of therapies—is not well defined. In order to obtain the best clinical outcomes, patients need to be treated with the therapies that are most likely to provide benefit and avoid toxic therapies that are unlikely to be effective. Ideally, predictive biomarkers that allow for the selection of the therapies most likely to be of benefit would be employed for each treatment decision. In practice, biomarkers including tumor molecular sequencing, circulating tumor DNA, circulating tumor cell enumeration and androgen receptor characteristics, and tumor cell surface expression (PSMA), all may have a role in therapy selection. In this review, we define the established prognostic and predictive biomarkers for therapy in advanced prostate cancer and explore emerging biomarkers.

A Prospective Study of the Relationship Between Clinical Outcomes After Enzalutamide and Serum Androgen Levels Measured via Liquid Chromatography-tandem Mass Spectrometry in Patients with Castration-resistant Prostate Cancer

Background

Enzalutamide (ENZ) is used to treat patients with castration-resistant prostate cancer (CRPC). However, the kinetics of serum androgens before and after ENZ treatment are unknown.

Objective

To elucidate the kinetics of serum androgens and explore the possibility of identifying a useful marker for predicting the effects of ENZ.

Design setting and participants

We conducted a prospective study from 2014 to 2018 at Gunma University Hospital and related facilities. Data were analyzed for 104 patients with CRPC treated with ENZ.

Outcome measurements and statistical analysis

We measured serum androgen levels using liquid chromatography-tandem mass spectrometry. Relationships with outcomes were assessed using multivariable Cox regression and log-rank analyses.

Results and limitations

The median age of the patients was 73 yr. Median serum testosterone, dihydrotestosterone (DHT), androstenedione, and dehydroepiandrosterone sulfate levels were 49.0, 5.8, 222.2, and 326.3 pg/ml, respectively. We performed multivariate analysis using Cox regression to predict prostate-specific antigen progression-free survival (PSA-PFS) and overall survival (OS). Hemoglobin level (≥12.5 vs <12.5 g/dl), docetaxel treatment history (no vs yes), and DHT level (≥5.9 vs <5.9 pg/ml) were significant predictors of PSA-PFS (p <  0.05). Eastern Cooperative Oncology Group performance status (0 vs. 1-2), hemoglobin level (≥12.5 vs <12.5 g/dl), presence of visceral metastasis (no vs yes), amount of bone metastasis (extent of disease 0-2 vs 3-4), and docetaxel treatment history (no vs yes) were significant predictors of OS (p <  0.05). Binomial logistic analysis of the predictors of any grade of anorexia, malaise, and fatigue showed that the presence of visceral metastasis and a low DHT level (<5.9 pg/ml) were significant.

Conclusions

Our results suggest that serum androgen levels before ENZ treatment may be useful for predicting efficacy, prognosis, and the incidence of adverse events.

Patient summary

We measured blood levels of testosterone and other male hormones before treatment with enzalutamide among men with prostate cancer resistant to castration. We found that the levels of these hormones may be useful for predicting the efficacy of enzalutamide treatment, prognosis, and the occurrence of adverse side effects.

Serum testosterone levels and testosterone 'bounce' phenomenon predict response to novel anti-androgen therapies in castration-resistant prostate cancer

BACKGROUND

The relevance of continuous testosterone (TT) monitoring in castration-resistant prostate cancer (CRPC) remains in question.

OBJECTIVE

To determine if TT levels before and during novel anti-androgen therapies (NAAT), and the TT 'bounce' phenomenon may predict treatment response in CRPC.

MATERIALS AND METHODS

From 2014 through 2018, we identified 92 CRPC patients treated with either Abiraterone or Enzalutamide from a prospectively maintained cancer registry. The TT levels measured before and during NAAT were correlated with the oncological outcomes, determined by PSA response (% change), PSA progression-free survival (PFS) and overall survival (OS).

RESULTS AND LIMITATIONS

At CRPC, 58 (63.0%) and 34 (37.0%) patients opted for Abiraterone and Enzalutamide respectively. Median TT levels at CRPC status before and during NAAT were 10.37 ng/dl and 20.46 ng/dl respectively. PSA response was superior in patients with a higher TT before NAAT (P:0.048, median difference: 18.22%, 95% CI 0.70 - 40.37) and longer time to CRPC (P: 0.041, median difference: 15.31%, 95% CI 1.84 -34.84), with a trend towards lower TT during NAAT (P: 0.062). Over a follow up of 33.0 months, 65 patients (70.7%) developed PSA progression. PSA PFS was longer in patients with higher TT before NAAT (16.3 vs. 10.8 months; P: 0.023), lower TT during NAAT (17.0 vs. 9.1 months; P: 0.001), and longer time to CRPC (13.4 vs. 8.0 months; P: 0.032). Importantly, better OS was observed in lower TT during NAAT (45.0 vs. 33.0 months; P:0.029) and longer time to CRPC (43.0 vs. 31.0 months; P: 0.025). The TT 'bounce' phenomenon was observed in 28 patients (33.3%), and was associated with a poorer PSA response (P: 0.029, median difference: 18.90%, 95% CI 3.83 - 41.45), shorter PSA PFS (8.6 vs 15.2 months, P: 0.002) and shorter OS (29.0 vs. 45.0 months, P: 0.012).

CONCLUSION

In CRPC patients, TT behaviors before and during NAAT, and the 'bounce' phenomenon continue to predict treatment response and could guide clinical decisions.

Clinical implication of prognostic and predictive biomarkers for castration-resistant prostate cancer: a systematic review

Background

Diagnosis of metastatic castrate resistant prostate cancer (mCRPC) with current biomarkers is difficult and often results in unnecessary invasive procedures as well as over-diagnosis and over-treatment. There are a number of prognostic biomarkers for CRPC, but there are no validated predictive biomarkers to guide in clinical decision-making. Specific biomarkers are needed that enable to understand the natural history and complex biology of this heterogeneous malignancy, identify early response to treatment outcomes and to identify the population of men most likely to benefit from the treatment. In this systematic review, we discuss the existing literature for the role of biomarkers in CRPC and how they aid in the prognosis, treatment selection and survival outcomes.

Methods

We performed a literature search on PubMed and EMBASE databases from January 2015 through February 2020 in accordance to Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Articles were assessed to identify relevant observational studies and randomized controlled trials regarding biomarkers which aid in identifying progression to mCRPC as well as predictive biomarkers which help in treatment selection.

Results

We identified 3640 number of hits of which 58 articles were found to be relevant. Here we addressed biomarkers in the context of prognosis, prediction and patient selection of therapy. These biomarkers were found to be effective as prognostic or predictive factors under variety of conditions. The higher levels for all these biomarkers were associated with shorter median OS and sometimes PFS. Lower amounts of biomarkers in serum or urine were associated with prolonged survival outcomes, longer time to CRPC development or CRPC progression and longer median follow-up irrespective of any therapy.

Conclusion

We observed that the biomarkers included in our study predicted clinically relevant survival outcomes and treatment exposure. Though the current biomarkers are prognostic when measured prior to initiating treatment, not all are validated as predictive markers in post treatment setting. A greater understanding of biomarkers in CRPC is need of the hour for development of more personalized approach to maximize benefit and minimize harm in men with CRPC.

Emerging promising biomarkers for treatment decision in metastatic castration-resistant prostate cancer

Prostate cancer is one of the most common causes of death in males. Even if treatment is often of curative intent in early stages of the disease, up to 50% of patients relapse after primary therapy. Moreover, 10% to 15% of patients present in a primary metastatic stage of disease. In the past years the treatment landscape of metastatic castration-resistant prostate cancer expanded due to the development of second-generation antiandrogens (abiraterone acetate, enzalutamide), chemotherapeutic agents and radium-223. With the availability of several therapeutic lines, we are now confronted with the problem of choosing the most suitable therapy in each state of disease. As often observed in clinical routine, prostate specific antigen is not sufficient for early prediction of a therapy response. Furthermore, biomarkers for prediction of the optimal first-line therapy are badly needed in order to avoid primary resistance. Therefore, the present short review article gives an overview of currently available clinical and preclinical biomarkers for treatment response to metastatic castration-resistant prostate cancer therapeutic agents with the aim of providing support for a personalized decision-making process in everyday use.

Blood platelet volume predicts treatment-specific outcomes of metastatic castration-resistant prostate cancer

BACKGROUND

In the present guidelines for the management of metastatic castration-resistant prostate cancer (mCRPC), it is unclear who benefits most from androgen receptor axis-targeted agents (ARATs) or docetaxel as the first-line treatment.

METHODS

We conducted a retrospective study to explore new treatment-specific biomarkers in mCRPC. A total of 211 patients with mCRPC who received either ARAT or docetaxel as first-line treatment were included. Patients were compared for radiographic progression and prostate-specific antigen (PSA) progression. Multivariable Cox regression models were used to assess the association between pretreatment biomarkers and risk of events. The statistical interaction between biomarkers and clinical outcomes was also evaluated.

RESULTS

Of all analyzed biomarkers, multivariable Cox regression models identified MPV [≤ median (9.7 fL)] as an independent prognostic factor of radiographic progression [hazard ratio (HR), 2.35; 95% confidence interval (CI), 1.15-4.80; P = 0.019] and PSA progression (HR, 1.96; 95% CI, 1.01-3.95; P = 0.048) in patients treated with ARAT, whereas such associations were not observed in those treated with docetaxel. Interaction analyses showed that those initially treated with docetaxel have lower risk of radiographic progression (HR, 0.33; 95% CI, 0.13-0.79; P = 0.014) and PSA progression (HR, 0.48; 95% CI, 0.23-0.98; P = 0.044) than ARAT when MPV was small.

CONCLUSIONS

The present study identified pretreatment MPV as a significant treatment-specific prognostic factor of PSA and radiographic progression in patients with mCRPC who received first-line treatment. Furthermore, our results suggested that those with small MPV may better be treated initially with docetaxel than ARAT.

Higher serum testosterone levels predict poor prognosis in castration-resistant prostate cancer patients treated with docetaxel

BACKGROUND

The role of testosterone as a prognostic factor for castration-resistant prostate cancer treated with docetaxel in Japan was investigated.

METHODS

A total of 164 patients with castration-resistant prostate cancer who received docetaxel treatment at Chiba University Hospital and an affiliated hospital were retrospectively analyzed. Testosterone and other clinical factors at the start of docetaxel treatment were evaluated with respect to overall survival and progression-free survival.

RESULTS

Of the 164 patients, 69 had high-volume tumors. The median prostatic-specific antigen was 27.0 ng/mL. The median testosterone was 13.0 ng/dL. The rates of bone and visceral metastases were 80.1% and 8.8%, respectively. For progression-free survival, testosterone ≥13 ng/dL was an independent prognostic factor only on univariate analysis (hazard ratio, 1.81; P = .0108). For overall survival, testosterone ≥ 1.3 ng/dL (hazard ratio, 3.37; P < .0001), high volume (hazard ratio, 3.06; P = .0009), and prostate-specific antigen ≥ 27.0 ng/mL (hazard ratio, 2.75; P = .0013) were independent prognostic factors on multivariate analysis. When assessing related clinical factors, higher serum testosterone was associated with visceral metastasis, high volume, and prostate-specific antigen. Based on three prognostic factors (testosterone, high volume, prostate-specific antigen), a risk classification was developed. The high-risk group (3 risk factors) showed a significantly shorter overall survival compared to the moderate-risk (2 risk factors) and low-risk (0-1 risk factor) groups (P < .0001).

CONCLUSIONS

The present study identified higher serum testosterone (≥13 ng/dL) as a significant prognostic factor in castration-resistant prostate cancer patients treated with docetaxel therapy.

How do we define "castration" in men on androgen deprivation therapy?

Androgen deprivation therapy (ADT) is the mainstay for the treatment of advanced prostate cancer. Since the clinical evolution from surgical orchiectomy, we have typically used ADT and orchiectomy to be synonymous terms for castration. The goal of this study is to determine if, in contemporary medical practice, surgical and chemical castration provide for similar levels of diminishment of total and free testosterone. Further, what approaches should be used to most accurately measure testosterone levels in men with advanced prostate cancer and what cutoff values, for example for total testosterone 50 ng dl^-1 or 20 ng dl^-1, should be utilized. Studies available in the literature have been analyzed and compiled to address these questions. Finally, evidence is provided that free testosterone, the biologically active component, should be utilized to provide clinically relevant state of castration.

Prognostic value of testosterone for the castration-resistant prostate cancer patients: a systematic review and meta-analysis

INTRODUCTION

This systematic review and meta-analysis aimed to assess the prognostic value of testosterone in patients with castration-resistant prostate cancer (CRPC).

MATERIALS AND METHODS

PubMed, Web of Science, and Scopus databases were systematically searched until December 2019, according to the Preferred Reporting Items for Systemic Review and Meta-analysis statement. The endpoints were progression-free survival (PFS) and overall survival (OS).

RESULTS

We identified 11 articles with 4206 patients for systematic review and nine articles with 4136 patients for meta-analysis. Higher testosterone levels were significantly associated with better OS (pooled HR 0.74, 95% CI 0.58-0.95) and better PFS (pooled HR 0.51, 95% CI 0.30-0.87). Subgroup analyses based on the treatment type revealed that higher testosterone levels were significantly associated with better OS in CRPC patients treated with androgen receptor-targeted agents (ARTAs) (pooled HR 0.64, 95% CI 0.55-0.75), but not in those treated with chemotherapy (pooled HR 0.78, 95% CI 0.53-1.14).

CONCLUSION

This meta-analysis demonstrated that the PFS and OS were significantly greater in patients with CRPC in those with higher testosterone levels than that of those with lower testosterone levels. In the subgroup analyses, lower testosterone levels were a consistently poor prognostic factor for OS in patients treated with ARTAs, but not in those treated with chemotherapy. Therefore, higher testosterone levels could be a useful biomarker to identify patient subgroups in which ARTAs should be preferentially recommended in the CRPC setting.