Serial Biopsy Results in Prostate Cancer Screening Study:

DNA Methylation-Mediated Lowly Expressed AOX1 Promotes Cell Migration and Invasion of Prostate Cancer

INTRODUCTION

DNA methylation regulates gene transcriptional functions in the pathogenesis of malignant diseases. In prostate cancer, several tumor suppressors are known to be tumor specifically methylated.

METHODS

In this study, 450K methylation data and mRNA expression data were accessed from The Cancer Genome Atlas-Prostate Adenocarcinoma database and analyzed bioinformatically. Methylation-specific PCR was used to examine the methylation condition in AOX1 promoter. qRT-PCR was applied to measure the mRNA expression of AOX1. Western blot was employed to detect the expressions of AOX1 and the EMT associated proteins. Transwell and scratch healing assays were used to examine the invasive and migratory abilities of the prostate cancer cells respectively.

RESULTS

AOX1 was lowly expressed and hypermethylated in the prostate cancer tissues and cells. Also, AOX1 was downregulated at protein level in prostate cancer cells. Knocking down AOX1 could promote cell migration and invasion in the prostate cancer cells. By using a DNA methylation inhibitor, 5-AzadC was found to promote the expression of AOX1 and reverse the promoting effects of short interfering RNA against AOX1 on cell migration and invasion.

CONCLUSION

This study suggested that DNA methylation and low AOX1 level might be biomarkers for prostate cancer.

Susceptibility artifacts and PIRADS 3 lesions in prostatic MRI: how often is the dynamic contrast-enhance sequence necessary?

PURPOSE

To assess the need of the dynamic contrast-enhanced (DCE) sequence in addition to T2-weighted imaging (T2-WI) and diffusion-weighted imaging (DWI) for the detection of clinically significant prostate cancer in the presence of artifacts associated with rectal gas (which compromise the diffusion assessment) and/or PIRADS 3 lesions.

METHODS

This retrospective study was approved by the institutional review board; informed consent was not required. Patients referred consecutively over a period of 5 months for elevated PSA underwent multiparametric magnetic resonance imaging (mpMRI). mpMRI was performed using a 3T MRI system without an endorectal coil. The MRI findings were reviewed by two radiologists and were scored according to the Prostate Imaging Reporting and Data System version 2.0 (PI-RADSv2). Any discrepancies were resolved by consensus. For statistical purposes, lesions were classified as PIRADS 1-2, PIRADS 3, or PIRADS 4-5. First, all studies were reviewed using a biparametric assessment (T2-WI + DWI), and the presence or absence of susceptibility artifacts was assessed for each prostate. Subsequently, all images were analyzed using the standard multiparametric approach (T2-WI + DWI + DCE).

RESULTS

The biparametric evaluation (T2-WI + DWI) showed artifacts (due to the presence of rectal gas or other) in 87 patients (43.5%) and no artifacts in 113 patients (56.5%). In the latter group, 15 patients had peripheral zone (PZ) PIRADS 3 lesions. Thus, a total of 102 patients (51%) had artifacts or PZ PIRADS 3 lesions and therefore required DCE. When evaluating the group of prostates without artifacts, 13.3% of prostates required DCE. A total of 17 (23.9%) PIRADS 4-5 prostate lesions would have not been detected without the use of DCE.

CONCLUSION

Biparametric evaluation of the prostate revealed some limitation due to the presence of artifacts or PIRADS 3 PZ lesions. Artifacts were present in almost 44% of our patients, but when the DWI was correctly evaluated, only 13.3% of prostates required DCE.

Management of men with a suspicion of prostate cancer after negative initial prostate biopsy results

INTRODUCTION

For men with elevated prostate-specific antigen (PSA), appropriate management after negative prostate biopsy remains controversial. After determining PSA kinetics, subsequent follow-up was considered.

PATIENTS AND METHODS

A total of 115 cases with negative repeat biopsy were followed by evaluating PSA kinetics and ratio of percent free PSA (F/T) and by performing second repeat biopsy.

RESULTS

Eighteen cancer cases were diagnosed. Shorter PSA doubling times and faster velocities were found in cancer cases compared with cases without cancer. We observed a clear decrease in F/T among cancer cases.

CONCLUSIONS

To avoid unnecessary repeat biopsies, cases with a suspicion of cancer after negative biopsy can be divided into two groups: one that requires additional biopsies and one with an average change in PSA of <1 ng/ml/year and no change in F/T, which is recommended for surveillance as stable disease without biopsy over a specified time period.

The antibody response to Propionibacterium acnes is an independent predictor of serum prostate-specific antigen levels in biopsy-negative men

OBJECTIVE

To investigate whether the serum titres of Propionibacterium acnes antibodies in patients undergoing prostate biopsy are associated with prostate cancer or markers of prostate disease, including serum prostate-specific antigen (PSA) levels.

PATIENTS AND METHODS

The cell wall-associated proteins from P. acnes types IA, IB and II were extracted and characterized by Western blotting and immunoblotting. We developed an enzyme-linked immunosorbent assay (ELISA) based on extracted proteins to determine the anti-P. acnes antibody titres in the sera of 68 patients undergoing prostate biopsy. Correlations between these titres and multiple markers of prostate disease were investigated.

RESULTS

In patients with biopsies negative for cancer, a high anti-P. acnes antibody titre was associated with high serum PSA levels (>or=10.0 ng/mL, P = 0.04), and multiple linear regression analysis identified antibody titre as the predominant independent predictor of serum PSA level (P = 0.03). The titre was positively correlated with patient age, prostate volume and aggressive inflammation, suggesting an involvement with benign prostatic hyperplasia (BPH). However in patients with histologically detected cancer, the volume of cancer in the biopsy cores was the predominant independent predictor of serum PSA (P = 0.01).

CONCLUSIONS

These results support our hypothesis that P. acnes might be involved in the development of inflammation-related prostate diseases, in particular with BPH. Our ELISA might be valuable for identifying P. acnes infection of the prostate gland in patients with elevated serum PSA levels but a negative biopsy, and might identify men at risk of developing clinical BPH. However, an investigation with more patients is needed to confirm these preliminary findings.

Comparison of traditional basal and apical periprostatic block: impact on injection pain and biopsy pain

OBJECTIVE

To compare the pain of injection and biopsy when lidocaine is injected periprostatically either at a basal or apical site, as the former is commonly used to anaesthetise the prostate, based on several reports showing that it can eliminate most of the pain associated with prostate biopsy, and this site has been favoured over apical injection because the nerves enter the prostate from the basal aspect.

PATIENTS AND METHODS

In all, 143 patients scheduled for biopsy were randomized to receive a periprostatic block either at the apex or base of the prostate. Immediately before biopsy 5 mL of 1% lidocaine was injected under transrectal ultrasonographic (TRUS) guidance into the periprostatic nerves bilaterally. Patients were immediately given a 100 mm visual analogue scale (VAS, 0-100) to assess the pain associated with both the block and the subsequent biopsy.

RESULTS

The mean VAS scores for the anaesthetic block were 21.1 and 22.0 (P = 0.79) and the biopsy VAS scores were 17.6 and 28.7 (P < 0.001) for the apical and basal groups, respectively. There was no statistically significant difference between patients who had a 12- or 20-core biopsy.

CONCLUSIONS

Apical periprostatic injection with anaesthetic provides better anaesthesia for TRUS biopsy than basal injection, and without increasing the pain associated with injection at the potentially more sensitive apical site.

Variation in patterns of practice in diagnosing screen-detected prostate cancer

OBJECTIVE

To determine the practice pattern of repeat prostate biopsies to detect prostate cancer, as there is growing evidence to support the recommendation that a repeat prostate biopsy should be taken after an initially negative prostate biopsy, the rate of cancer detection then being approximately 30%.

PATIENTS AND METHODS

We examined the practice patterns of taking a repeat prostate biopsy after an initial negative biopsy and the predictors for cancer at repeat biopsy among 1536 patients who had an initial prostate biopsy because of an elevated prostate-specific antigen (PSA) level (>4.0 ng/mL) or abnormal digital rectal examination.

RESULTS

Of the 1536 men, 712 (46.4%) had cancer detected on the first biopsy; of the remaining 824 with no cancer detected, 268 (32.5%) had a repeat biopsy within a year, and 68 of these (25.4%) had cancer detected. Of the cancers detected at repeat biopsy, 31% were high-grade. Men with abnormal histology (prostatic intraepithelial neoplasia or atypia) had an odds ratio of 3.2 (P < 0.001) for having a repeat biopsy. For men with normal initial prostate histology, those with an initial PSA of 10.0-20.0 and >20.0 ng/mL had an odds ratio of 3.6 and 4.5 (both P < 0.001), respectively, for a repeat prostate biopsy, compared with patients with a PSA of <10.0 ng/mL. However, the PSA level was not predictive of prostate cancer at repeat biopsy, but age and prostate volume were.

CONCLUSIONS

A third of patients had a repeat biopsy after a negative biopsy. The most important factors influencing whether a patient was to have a repeat biopsy were initial biopsy histology and PSA level. However, the latter was not an important factor for predicting prostate cancer at repeat biopsy.

Intravenous Ketorolac Significantly Reduces the Pain of Office Transrectal Ultrasound and Prostate Biopsies

INTRODUCTION

Campbell's' Urology, 8th edition, indicates that office transrectal ultrasound (TRUS) and prostate biopsies require no anesthesia. This is however in contradistinction from the experience of patients who have had the procedure. A study was conducted to evaluate whether 60 mg of intravenous Ketorolac before the procedure makes it more tolerable.

MATERIAL AND METHODS

A prospective study was performed involving 24 patients who were randomized into two groups. One group was given 60 mg of Ketorolac intravenously before the procedure and the control group received no analgesia.

RESULTS

The two groups were comparable in age and the indications for the TRUS and prostate biopsies. The number of biopsy cores tolerated and taken was significantly less in the control group than in the group that was given intravenous Ketorolac. The degree of pain in the group that had intravenous Ketorolac was significantly less than in the no analgesia group.

CONCLUSION

TRUS with prostate biopsies is a painful procedure. Intravenous Ketorolac significantly reduces the pain involved in the procedure and allows patients to tolerate it better for a more complete procedure.

Effectiveness of percent free prostate specific antigen as a predictor of prostate cancer detection on repeat biopsy

BACKGROUND

The aim of this study was to identify predictors that can increase the accuracy of detecting prostate cancer on subsequent biopsies.

METHODS

Between 1998 and 2003, a total of 235 men with prostate specific antigen (PSA) levels between 4.0 and 20 ng/mL underwent one or more systematic needle biopsies of the prostate. Of these men, 73 (31.1%) underwent one repeat biopsy and 26 (11.1%) underwent two or more repeat biopsies. We evaluated the results of prostate biopsies in relation to the morbidity of prostate cancer detected on repeat biopsies.

RESULTS

Of the 73 men who underwent repeat biopsy, 16 (21.9%) had prostate cancer. Twenty-six men with one negative re-biopsy underwent two or more repeat biopsies, and five of these patients were found to have early stage prostate cancer. On repeat biopsy, there was a significant difference in percent free PSA between the cancer-detected group and the no-cancer-detected group (P < 0.01). A receiver operating characteristics (ROC) curve gave an optimal cut-off value for percent free PSA of 11%, demonstrating a significant difference in the cancer detection rate on repeat biopsy (P = 0.0009). Analysis of the data for re-biopsies showed that cancer-detected cases showed a raised PSA value and a simultaneously reduced percent free PSA (these differences were statistically significant).

CONCLUSIONS

A low percent free PSA level increased the probability of a positive result in repeat biopsy. An increase in the accuracy of detecting cancer, especially on repeat biopsy, will promote the detection of more early stage prostate cancer.