Usefulness of Prostate-Specific Antigen Nadir as Predictor of Androgen-Independent Progression of Metastatic Prostate Cancer

Prognostic significance of nadir PSA value and time to nadir PSA in patients with metastatic castration-naive prostate cancer receiving first-line hormonotherapy

BACKGROUND

The current study aimed to evaluate the effect of the time duration to reach the lowest prostate-specific antigen (PSA) from the onset of first-line hormonal treatment (time to nadir PSA, TTNpsa) on survival in castration-naive metastatic prostate cancer (CN-MPC) patients.

METHODS

Eighty patients who had PSA response >80% with first-line hormonal therapy (luteinizing hormone-releasing hormone, LH-RH analog +/- bicalutamide) were included in this study.

RESULTS

Under androgen deprivation therapy (ADT), a significant positive correlation was found between TTNpsa, nadir PSA (Npsa) duration, and progression-free survival (PFS) ( p < 0.001) and overall survival (OS) ( p < 0.001). There was no correlation between TTNpsa and Npsa duration. TTNpsa and Npsa durations were independently correlated with PFS and OS. In patients with TTNpsa value ≥19 weeks, the median PFS was 126 (95% CI, 68-184) weeks compared with TTNpsa <19-week group in which the median PFS was 44 (95% CI, 26-62) weeks ( p = 0.033). In patients with TTNpsa value ≥19 weeks, the median OS was 242 (95% CI, 169-315) weeks compared with TTNpsa <19-week group in which the OS was 156 (95% CI, 89-223) weeks ( p = 0.018). The median nadir PSA value was 1 ng/mL. The median PFS was significantly longer in the patient group with ≤1 ng/mL (137 weeks, 95% CI, 50-224) compared with the group with >1 ng/mL (41 weeks, 95% CI, 34-48) ( p < 0.001). The median OS was significantly longer in the patient group with nadir PSA ≤1 ng/mL (296 weeks, 95% CI, 220-272) compared to the group with >1 ng/mL (131 weeks, 95% CI, 84-178) ( p = 0.002). In patients with nadir PSA ≤1 ng/mL ( n = 40), there was no relationship between TTNpsa and Npsa duration with both PFS and OS. However, in patients with nadir PSA >1 ng/mL ( n = 40) subgroup, there was a significant positive correlation between TTNpsa and PFS, and OS ( p < 0.001, P = 0.016, respectively).

CONCLUSION

In CN-MPC who received first-line ADT, especially in the group with the nadir PSA value >1 ng/mL, the duration of TTNpsa was positively correlated with PFS and OS.

The Importance of Time to Prostate-Specific Antigen (PSA) Nadir after Primary Androgen Deprivation Therapy in Hormone-Naïve Prostate Cancer Patients

Prostate-specific antigen (PSA) is currently the most useful biomarker for detection of prostate cancer (PCa). The ability to measure serum PSA levels has affected all aspects of PCa management over the past two decades. The standard initial systemic therapy for advanced PCa is androgen-deprivation therapy (ADT). Although PCa patients with metastatic disease initially respond well to ADT, they often progress to castration-resistant prostate cancer (CRPC), which has a high mortality rate. We have demonstrated that time to PSA nadir (TTN) after primary ADT is an important early predictor of overall survival and progression-free survival for advanced PCa patients. In in vivo experiments, we demonstrated that the presence of fibroblasts in the PCa tumor microenvironment can prolong the period for serum PSA decline after ADT, and enhance the efficacy of ADT. Clarification of the mechanisms that affect TTN after ADT could be useful to guide selection of optimal PCa treatment strategies. In this review, we discuss recent in vitro and in vivo findings concerning the involvement of stromal–epithelial interactions in the biological mechanism of TTN after ADT to support the novel concept of “tumor regulating fibroblasts”.

Mt-rps3 is an ancient gene which provides insight into the evolution of fungal mitochondrial genomes

The nuclear ribosomal protein S3 (Rps3) is implicated in the assembly of the ribosomal small subunit. Fungi and plants present a gene copy in their mitochondrial (mt) genomes. An analysis of 303 complete fungal mt genomes showed that, when rps3 is found, it is either a free-standing gene or an anchored gene within the omega intron of the rnl gene. Early divergent fungi, Basidiomycota and all yeasts but the CTG group belong to the first case, and Pezizomycotina to the second. Its position, size and genetic code employed are conserved within species of the same Order. Size variability is attributed to different number of repeats. These repeats consist of AT-rich sequences. MtRps3 proteins lack the KH domain, necessary for binding to rRNA, in their N-terminal region. Their C-terminal region is conserved in all Domains of life. Phylogenetic analysis showed that nuclear and mtRps3 proteins are descendants of archaeal and a-proteobacterial homologues, respectively. Thus, fungal mt-rps3 gene is an ancient gene which evolved within the endosymbiotic model and presents different evolutionary routes: (a) coming from a-proteobacteria, it was relocated to another region of the mt genome, (b) via its insertion to the omega intron, it was transferred to the nucleus and/or got lost, and (c) it was re-routed to the mt genome again. Today, Basidiomycota and Saccharomycetales seem to follow the first evolutionary route and almost all Pezizomycotina support the second scenario with their exceptions being the result of the third scenario, i.e., the gene's re-entry to the mt genome.

Prostate specific antigen (PSA) kinetic as a prognostic factor in metastatic prostate cancer receiving androgen deprivation therapy: systematic review and meta-analysis

Aim: Metastatic prostate cancer (mPCa) has a poor outcome with median survival of two to five years. The use of androgen deprivation therapy (ADT) is a gold standard in management of this stage.  Aim of this study is to analyze the prognostic value of PSA kinetics of patient treated with hormonal therapy related to survival from several published studies Method: Systematic review and meta-analysis was performed using literature searching in the electronic databases of MEDLINE, Science Direct, and Cochrane Library. Inclusion criteria were mPCa receiving ADT, a study analyzing Progression Free Survival (PFS), Overall Survival (OS), or Cancer Specific Survival (CSS) and prognostic factor of survival related to PSA kinetics (initial PSA, PSA nadir, and time to achieve nadir (TTN)). The exclusion criteria were metastatic castration resistant of prostate cancer (mCRPC) and non-metastatic disease. Generic inverse variance method was used to combine hazard ratio (HR) within the studies. Meta-analysis was performed using Review Manager 5.2 and a p-value <0.05 was considered statistically significant. Results: We found 873 citations throughout database searching with 17 studies were consistent with inclusion criteria. However, just 10 studies were analyzed in the quantitative analysis. Most of the studies had a good methodological quality based on Ottawa Scale. No significant association between initial PSA and PFS. In addition, there was no association between initial PSA and CSS/ OS. We found association of reduced PFS (HR 2.22; 95% CI 1.82 to 2.70) and OS/ CSS (HR 3.31; 95% CI 2.01-5.43) of patient with high PSA nadir. Shorter TTN was correlated with poor result of survival either PFS (HR 2.41; 95% CI 1.19 - 4.86) or CSS/ OS (HR 1.80; 95%CI  1.42 - 2.30) Conclusion: Initial PSA before starting ADT do not associated with survival in mPCa.  There is association of PSA nadir and TTN with survival.

Inhibition of androgen receptor by decoy molecules delays progression to castration-recurrent prostate cancer

Androgen receptor (AR) is a member of the steroid receptor family and a therapeutic target for all stages of prostate cancer. AR is activated by ligand binding within its C-terminus ligand-binding domain (LBD). Here we show that overexpression of the AR NTD to generate decoy molecules inhibited both the growth and progression of prostate cancer in castrated hosts. Specifically, it was shown that lentivirus delivery of decoys delayed hormonal progression in castrated hosts as indicated by increased doubling time of tumor volume, prolonged time to achieve pre-castrate levels of serum prostate-specific antigen (PSA) and PSA nadir. These clinical parameters are indicative of delayed hormonal progression and improved therapeutic response and prognosis. Decoys reduced the expression of androgen-regulated genes that correlated with reduced in situ interaction of the AR with androgen response elements. Decoys did not reduce levels of AR protein or prevent nuclear localization of the AR. Nor did decoys interact directly with the AR. Thus decoys did not inhibit AR transactivation by a dominant negative mechanism. This work provides evidence that the AR NTD plays an important role in the hormonal progression of prostate cancer and supports the development of AR antagonists that target the AR NTD.

Prognostic Impacts of Metastatic Site and Pain on Progression to Castrate Resistance and Mortality in Patients with Metastatic Prostate Cancer

PURPOSE

To investigate predictors of progression to castration-resistant prostate cancer (CRPC) and cancer-specific mortality (CSM) in patients with metastatic prostate cancer (mPCa).

MATERIALS AND METHODS

A retrospective analysis was performed on 440 consecutive treatment-naïve patients initially diagnosed with mPCa between August 2000 and June 2012. Patient age, body mass index (BMI), Gleason score, prostate-specific antigen (PSA), PSA nadir, American Joint Committee on Cancer stage, Visual Analogue Scale pain score, Eastern Cooperative Oncology Group performance score (ECOG PS), PSA response to hormone therapy, and metastatic sites were assessed. Cox-proportional hazards regression analyses were used to evaluate survivals and predictive variables of men with bone metastasis stratified according to the presence of pain, compared to men with visceral metastasis.

RESULTS

Metastases were most often found in bone (75.4%), followed by lung (16.3%) and liver (8.3%) tissues. Bone metastasis, pain, and high BMI were associated with increased risks of progression to CRPC, and bone metastasis, pain, PSA nadir, and ECOG PS≥1 were significant predictors of CSM. During the median follow-up of 32.0 (interquartile range 14.7-55.9) months, patients with bone metastasis with pain and patients with both bone and visceral metastases showed the worst median progression to CRPC-free and cancer-specific survivals, followed by men with bone metastasis without pain. Patients with visceral metastasis had the best median survivals.

CONCLUSION

Metastatic spread and pain patterns confer different prognosis in patients with mPCa. Bone may serve as a crucial microenvironment in the development of CRPC and disease progression.

Predictors of survival in prostate cancer patients with bone metastasis and extremely high prostate-specific antigen levels

PURPOSE

Prostate-specific antigen (PSA) is a surrogate marker of disease progression; however, its predictive ability in the extreme ranges is unknown. We determined the predictors of survival in patients with bone metastatic prostate cancer (BMPCa) and with extremely high PSA levels.

METHODS

Treatment-naïve patients (n = 248) diagnosed with BMPCa between December 2002 and June 2012 were retrospectively analyzed. Clinicopathological features at diagnosis, namely age, body mass index, serum alkaline phosphatase (ALP) and PSA levels, PSA nadir, time to PSA nadir and its maintenance period, PSA declining velocity, Gleason grade, clinical T stage, pain score, Eastern Cooperative Oncology Group performance score (ECOG PS), and the number of bone metastases were assessed. The patients were stratified according to PSA ranges of <20 ng/mL, 20-100 ng/mL, 100-1000 ng/mL, and 1000-10,000 ng/mL. Study endpoints were castration-resistant PCa (CRPC)-free survival and cancer-specific survival (CSS).

RESULTS

Patients with higher PSA and ALP levels showed more bone lesions (P < 0.001). During the follow-up period (median, 39.9 months; interquartile range, 21.5-65.9 months), there were no differences between the groups in terms of the survival endpoints. High ALP levels, shorter time to PSA nadir, and pain were associated with an increased risk of progression to CRPC, and high ALP levels, ECOG PS ≥ 1, and higher PSA nadir independently predicted CSS.

CONCLUSIONS

PSA response to androgen deprivation therapy and serum ALP are reliable predictors of survival in patients with BMPCa presenting with extremely high PSA levels. These patients should not be deterred from active treatment based on baseline PSA values.

Prostate-specific antigen nadir and time to prostate-specific antigen nadir following maximal androgen blockade independently predict prognosis in patients with metastatic prostate cancer

Purpose

To evaluate the influence of prostate-specific antigen (PSA) kinetics following maximal androgen blockade (MAB) on disease progression and cancer-specific survival in patients with metastatic, hormone-sensitive prostate cancer.

Materials and Methods

One hundred thirty-one patients with metastatic, hormone-sensitive prostate cancer treated with MAB at our institution were included in this study. Patients' characteristics, PSA at MAB initiation, PSA nadir, time to PSA nadir (TTN), and PSA decline were analyzed by using univariate and multivariate analysis.

Results

At a median follow-up of 30 months, 97 patients (74.0%) showed disease progression and 65 patients (49.6%) died. Fifty-nine patients (45.0%) died from prostate cancer. In the univariate analysis, PSA at MAB initiation, PSA nadir, TTN, and PSA decline were significant predictors of progression-free survival. Also, PSA nadir, TTN, and PSA decline were significant predictors of cancer-specific survival. In the multivariate analysis, higher PSA nadir (≥0.2 ng/ml) and shorter TTN (<8 months) were independent predictors of shorter progression-free and cancer-specific survival. In the combined analysis of PSA nadir and TTN, patients with higher PSA nadir and shorter TTN had the worst progression-free survival (hazard ratio [HR], 14.098; p<0.001) and cancer-specific survival (HR, 14.050; p<0.001) compared with those with lower PSA nadir and longer TTN.

Conclusions

Our results suggest that higher PSA nadir level and shorter TTN following MAB are associated with higher risk of disease progression and poorer survival in patients with metastatic, hormone-sensitive prostate cancer. Furthermore, these two variables have a synergistic effect on the outcome.

Predicting response to hormonal therapy and survival in men with hormone sensitive metastatic prostate cancer

Androgen deprivation is the cornerstone of the management of metastatic prostate cancer. Despite several decades of clinical experience with this therapy there are no standard predictive biomarkers for response. Although several candidate genetic, hormonal, inflammatory, biochemical, metabolic biomarkers have been suggested as potential predictors of response and outcome, none has been prospectively validated nor has proven clinical utility to date. There is significant heterogeneity in the depth and duration of hormonal response and in the natural history of advanced disease; therefore to better optimize/individualize therapy and for future development, identification of biomarkers is critical. This review summarizes the current data on the role of several candidate biomarkers that have been evaluated in the advanced/metastatic disease setting.

Prostate cancer

In developed countries, prostate cancer is the second most frequently diagnosed cancer, and the third most common cause of death from cancer in men. Apart from age and ethnic origin, a positive family history is probably the strongest known risk factor. Clinically, prostate cancer is diagnosed as local or advanced, and treatments range from surveillance to radical local treatment or androgen-deprivation treatment. Androgen deprivation reduces symptoms in about 70-80% of patients with advanced prostate cancer, but most tumours relapse within 2 years to an incurable androgen-independent state. The recorded incidence of prostate cancer has substantially increased in the past two decades, probably because of the introduction of screening with prostate-specific antigen, the use of improved biopsy techniques for diagnosis, and increased public awareness. Trends in mortality from the disease are less clearcut. Mortality changes are not of the same magnitude as the changes in incidence, and in some countries mortality has been stable or even decreased. The disparity between reported incidence and mortality rates leads to the probable conclusion that only a small proportion of diagnosed low-risk prostate cancers will progress to life-threatening disease during the lifetime of the patient.