The relationship between the androgen receptor CAG repeat polymorphism length and the response to intermittent androgen suppression therapy for advanced prostate cancer

Association of microRNA-21 expression with clinicopathological characteristics and the risk of progression in advanced prostate cancer patients receiving androgen deprivation therapy

BACKGROUND

Despite androgen deprivation therapy (ADT) remains the mainstay therapy for advanced prostate cancer (PCa), the patients have widely variable durations of response to ADT. Unfortunately, there is limited knowledge of pre-treatment prognostic factors for response to ADT. Recently, microRNA-21 (miR-21) has been reported to play an important role in development of castration resistance of CaP. However, little is known about the expression of miR-21 in advanced PCa biopsy tissues, and data on its potential predictive value in advanced PCa are completely lacking.

METHODS

In this study, paraffin-embedded prostate carcinoma tissues obtained by needle biopsy from 85 advanced PCa patients were evaluated for the expression levels of miR-21 by quantitative real-time PCR (qRT-PCR). In situ hybridization (ISH) analysis was performed to further confirm the qRT-PCR results. Kaplan-Meier analysis and Cox proportional hazards regression models were performed to investigate the correlation between miR-21 expression and time to progression of advanced PCa patients.

RESULTS

Compared with adjacent non-cancerous prostate tissues, the expression level of miR-21 was significantly increased in PCa tissues (PCa vs. non-cancerous prostate: 1.3273 ± 0.3207 vs. 0.9970 ± 0.2054, P < 0.001). By and large, in ISH analysis miR-21 was expressed at a higher level in tumor areas than in adjacent non-cancerous areas. Additionally, PCa patients with higher expression of miR-21 were significantly more likely to be of high Gleason score and high clinical stage (P < 0.05). There was no significant association between miR-21 expression and the initial prostate-specific antigen (PSA) level or age at diagnosis. Moreover, Kaplan-Meier survival analysis found that PCa patients with high miR-21 expression have shorter progression-free survival than those with low miR-21 expression. Furthermore, Multivariate Cox analysis revealed both miR-21 expression status (P = 0.040) and clinical stage (P = 0.042) were all independent predictive factor for progression-free survival for advanced PCa.

CONCLUSION

These findings suggest for the first time that the up-regulation of miR-21 may serve as an independent predictor of progress-free survival in patients with advanced PCa. Prostate 76:986-993, 2016. © 2016 Wiley Periodicals, Inc.

Molecular markers in sex hormone pathway genes associated with the efficacy of androgen-deprivation therapy for prostate cancer

Although most advanced prostate cancer patients respond to androgen-deprivation therapy (ADT), the efficacy is widely variable. We investigated whether the host genetic variations in sex hormone pathway genes are associated with the efficacy of ADT. A cohort of 645 patients with advanced prostate cancer treated with ADT was genotyped for 18 polymorphisms across 12 key genes involved in androgen and estrogen metabolism. We found that after adjusting for known risk factors in multivariate Cox regression models, AKR1C3 rs12529 and AR-CAG repeat length remained significantly associated with prostate cancer-specific mortality (PCSM) after ADT (P ≤ 0.041). Furthermore, individuals carrying two unfavorable genotypes at these loci presented a 13.7-fold increased risk of PCSM compared with individuals carrying zero (P<0.001). Our results identify two candidate molecular markers in key genes of androgen and estrogen pathways associated with PCSM after ADT, establishing the role of pharmacogenomics in this therapy.

Phase II trial of isoflavone in prostate-specific antigen recurrent prostate cancer after previous local therapy

BACKGROUND

Data exist that demonstrate isoflavones' potent antiproliferative effects on prostate cancer cells. We evaluated the efficacy of isoflavone in patients with PSA recurrent prostate cancer after prior therapy. We postulated that isoflavone therapy would slow the rate of rise of serum PSA.

METHODS

Twenty patients with rising PSA after prior local therapy were enrolled in this open-labeled, Phase II, nonrandomized trial (Trial registration # NCT00596895). Patients were treated with soy milk containing 47 mg of isoflavonoid per 8 oz serving three times per day for 12 months. Serum PSA, testosterone, lipids, isoflavone levels (genistein, daidzein, and equol), and quality of life (QOL) were measured at various time points from 0 to 12 months. PSA outcome was evaluated.

RESULTS

Within the mixed regression model, it was estimated that PSA had increased 56% per year before study entry and only increased 20% per year for the 12-month study period (p = 0.05). Specifically, the slope of PSA after study entry was significantly lower than that before study entry in 6 patients and the slope of PSA after study entry was significantly higher than before study entry in 2 patients. For the remaining 12 patients, the change in slope was statistically insignificant. Nearly two thirds of the patients were noted to have significant levels of free equol in their serum while on therapy.

CONCLUSION

Dietary intervention with isoflavone supplementation may have biologic activity in men with biochemical recurrent prostate cancer as shown by a decline in the slope of PSA. This study may lend support to the literature that nutritional supplements have biologic activity in prostate cancer and therefore, further studies with these agents in randomized clinical trials should be encouraged.

Primary combined androgen blockade in localized disease and its mechanism

In spite of clinical practice guidelines such as NCI-PDQ - in which primary androgen deprivation therapy (PADT) is not recommended as the primary treatment for localized prostate cancer - many patients have been treated with PADT. One of the reasons is that urologists themselves permit patients' desire because they know the effectiveness of PADT for some patients in their experiences. In this review we demonstrate basic mechanisms and the clinical efficacy of primary combined androgen blockade (PCAB) for localized or locally advanced prostate cancer. Then we discuss which patients are candidates for PCAB, and show that more than 30% of low- or intermediate-risk localized prostate cancers could be controlled in the long term with only PCAB. Short-term or intermittent PADT could not be recommended because of the possibilities of changing the character of the cancer cells by incomplete androgen ablation. We propose algorithms for the treatment of localized prostate cancer not only in low- and intermediate-risk groups but also in the high-risk group.

TGFB1 Single Nucleotide Polymorphisms Are Associated With Adverse Quality of Life in Prostate Cancer Patients Treated With Radiotherapy

PURPOSE

To investigate whether the presence of single nucleotide polymorphisms (SNPs) located within TGFB1 might be predictive for the development of adverse quality-of-life outcomes in prostate cancer patients treated with radiotherapy.

METHODS AND MATERIALS

A total of 141 prostate cancer patients treated with radiotherapy were screened for SNPs in TGFB1 using DNA sequencing. Three quality-of-life outcomes were investigated: (1) prospective decline in erectile function, (2) urinary quality of life, and (3) rectal bleeding. Median follow-up was 51.3 months (range, 12-138 months; SD, 24.4 months).

RESULTS

Those patients who possessed either the T/T genotype at position -509, the C/C genotype at position 869 (pro/pro, codon 10) or the G/C genotype at position 915 (arg/pro, codon 25) were significantly associated with the development of a decline in erectile function compared with those who did not have these genotypes: 56% (9 of 16) vs. 24% (11 of 45) (p = 0.02). In addition, patients with the -509 T/T genotype had a significantly increased risk of developing late rectal bleeding compared with those who had either the C/T or C/C genotype at this position: 55% (6 of 11) vs. 26% (34 of 130) (p = 0.05).

CONCLUSIONS

Possession of certain TGFB1 genotypes is associated with the development of both erectile dysfunction and late rectal bleeding in patients treated with radiotherapy for prostate cancer. Therefore, identification of patients harboring these genotypes may represent a means to predict which men are most likely to suffer from poor quality-of-life outcomes after radiotherapy for prostate cancer.

Intermittent versus continuous androgen suppression for prostatic cancer

BACKGROUND

After lung cancer, prostate cancer is the most common cause of death among males. The aim of treatment is to prevent disease-related morbidity and mortality while minimizing intervention-related adverse events. Androgen suppression therapy (AST) to reduce circulating serum testosterone and disease progression is considered a mainstay of treatment for men with advanced prostate cancer. It has been increasingly utilized for early stage disease despite a lack of evidence of effectiveness.

OBJECTIVES

Evaluate the effectiveness and safety of intermittent androgen suppression (IAS) compared to continuous androgen suppression for treating prostatic cancer.

SEARCH STRATEGY

The following databases were searched to identify randomised or quasi-randomised, controlled trials comparing intermittent and continuous androgen suppression in the treatment of any stage of prostate cancer: the Cochrane Central Register of Controlled Trials; EMBASE and LILACS.

SELECTION CRITERIA

Studies were included if they were randomised or quasi-randomized, and compare the effects of IAS versus CAS.

DATA COLLECTION AND ANALYSIS

Two reviewers selected relevant trials, assessed methodological quality and extracted data.

MAIN RESULTS

Five randomized studies involving 1382 patients were included in this review. All the included studies involved advanced (T3 or T4) prostate cancer, had relatively small populations, and were of short duration. Few events were reported and did not assess disease-specific survival or metastatic disease. Only one study (N = 77) evaluated biochemical outcomes. A subgroup analysis found no significant differences in biochemical progression (defined by the authors as PSA >/= 10 ng/mL) between IAS and CAS for Gleason scores 4 - 6, 7, and 8 - 10. For patients with a Gleason score > 6, reduction in biochemical progression favoured the IAS group (RR 0.10, 95% CI 0.01 to 0.67, P = 0.02). Studies primarily reported on adverse events. One trial (N = 43) found no difference in adverse effects (gastrointestinal, gynecomastia and asthenia) between IAS ( two events) and CAS (five events), with the exception of impotence, which was significantly lower in the IAS group (RR 0.72, 95% CI 0.56 to 0.92, P = 0.008).

AUTHORS' CONCLUSIONS

Data from RCTs comparing IAS to CAS are limited by small sample size and short duration. There are no data for the relative effectiveness of IAS versus CAS for overall survival, prostate cancer-specific survival, or disease progression. Limited information suggests IAS may have slightly reduced adverse events. Overall, IAS was also as effective as CAS for potency, but was superior during the interval of cycles (96%).

Molecular markers in the diagnosis of prostate cancer

The genetic alterations leading to prostate cancer are gradually being discovered. A wide variety of genes have been associated with prostate cancer development as well as tumor progression. Knowledge of gene polymorphisms associated with disease aid in the understanding of important pathways involved in this process and may result in the near future in clinical applications. Urinary molecular markers will soon be available to aid in the decision of repeat prostate biopsies. Recent findings suggest the importance of androgen signaling in disease development and progression. The further understanding of interaction of inflammation, diet, and genetic predisposition will improve risk stratification in the near future.

Molecular markers and their prognostic impact in patients with advanced prostate cancer undergoing intermittent androgen suppression

OBJECTIVE

Tumour features were evaluated during intermittent androgen suppression (IAS), and their prognostic impact on the first off-treatment time was analysed.

PATIENTS AND METHODS

Twenty patients with advanced prostate cancer underwent three consecutive prostate biopsies during the first cycle, namely at the beginning of androgen deprivation, 8 months after continuous therapy and at the time of prostate-specific antigen (PSA) progression above 20 ng/ml. Biopsy specimens were immunohistochemically processed and analysed for the apoptotic index (AI), Ki-67, p53 and Bcl-2 to investigate eventual changes over time. Correlations and regression analysis were performed to assess the prognostic significance of clinical and pathological parameters in predicting the first off-treatment time.

RESULTS

In contrast to the AI, p53 and Bcl-2, Ki-67 was the only marker that significantly changed over time (P=0.008). The first off-treatment time correlated significantly with pretreatment PSA (r=-0.594; P<0.01), testosterone recovery time (r=0.590; P=0.013) and biopsy grade (r=-0.738; P<0.01); only the latter gaining an independent factor in the multivariate analysis (P=0.022).

CONCLUSIONS

During IAS, Ki-67 was the only molecular marker that consistently changed over time. However, it did not correlate with off-treatment time that was predicted independently by the initial biopsy grade only. First off-treatment time was best predicted by clinical parameters and molecular markers from needle biopsies did not further contribute to a better patient selection.