Effect of Dutasteride Therapy on Doppler US Evaluation of Prostate: Preliminary Results

Improved multiparametric MRI discrimination between low-risk prostate cancer and benign tissues in a small cohort of 5α-reductase inhibitor treated individuals as compared with an untreated cohort

The purpose of this study was to determine whether 5α-reductase inhibitors (5-ARIs) affect the discrimination between low-grade prostate cancer and benign tissues on multiparametric MRI (mpMRI). Twenty men with biopsy-proven Gleason 3 + 3 prostate cancer and 3 T mpMRI were studied. Ten patients (Tx) had been receiving 5-ARIs for at least a year at scan time. Ten untreated patients (Un) were matched to the treated cohort. For each subject two regions of interest representing cancerous and benign tissues were drawn within the peripheral zone of each prostate, MR measures evaluated, and cancer contrast versus benign (contrast = (MR_Tumor  - MR_Healthy )/MR_Healthy ) calculated. Decreased cancer contrast was noted on T₂ -weighted images: 0.4 (Un) versus 0.3 (Tx). However, for functional MR measures, a better separation of cancerous and benign tissues was observed in the treated group. Cancer contrast on high-b diffusion-weighted imaging (DWI) was 0.61 (Un) versus 0.99 (Tx). Logistic regression analysis yielded higher AUC (area under the curve) values for distinguishing cancerous from benign regions in treated subjects on high-b DWI (0.71 (Un), 0.94 (Tx)), maximal enhancement slope (0.95 (Un), 1 (Tx)), peak enhancement (0.84 (Un), 0.93 (Tx)), washout slope (0.78 (Un), 0.99 (Tx)), K^trans (0.9 (Un), 1 (Tx)), and combined measures (0.86 (Un), 0.99 (Tx)). Coefficients of variation for MR measures were lower in benign and cancerous tissues in the treated group compared with the untreated group. This study's results suggest an increase in homogeneity of benign and malignant peripheral zone prostatic tissues with 5-ARI exposure, observed as reduced variability of MR measures after treatment. Cancer discrimination was lower with T₂ -weighted imaging, but was higher with functional MR measures in a 5-ARI-treated cohort compared with controls.

Novel trends in transrectal ultrasound imaging of prostate gland carcinoma

Carcinoma of the prostate gland is the most common neoplasm in men. Its treatment depends on multiple factors among which local staging plays a significant role. The basic method is transrectal ultrasound imaging. This examination enables imaging of the prostate gland and its abnormalities, but it also allows ultrasound-guided biopsies to be conducted. A conventional gray-scale ultrasound examination enables assessment of the size, echostructure and outlines of the anatomic capsule, but in many cases, neoplastic lesions cannot be observed. For this reason, new sonographic techniques are implemented in order to facilitate detectability of cancer. The usage of contrast agents during transrectal ultrasound examination must be emphasized since, in combination with color Doppler, it facilitates detection of cancerous lesions by visualizing flow which is not observable without contrast enhancement. Elastography, in turn, is a different solution. It uses the differences in tissue elasticity between a neoplastic region and normal prostatic parenchyma that surrounds it. This technique facilitates detection of lesions irrespective of their echogenicity and thereby supplements conventional transrectal examinations. However, the size of the prostate gland and its relatively far location from the transducer may constitute limitations to the effectiveness of elastography. Moreover, the manner of conducting such an examination depends on the examiner and his or her subjective assessment. Another method, which falls within the novel, popular trend of combining imaging methods, is fusion of magnetic resonance imaging and transrectal sonography. The application of multidimensional magnetic resonance imaging, which is currently believed to be the best method for prostate cancer staging, in combination with the availability of a TRUS examination and the possibility of monitoring biopsies in real-time sonography is a promising alternative, but it is associated with higher costs and longer duration of the examination. This paper presents the most important novel trends in transrectal imaging in prostate cancer diagnosis based on the review of the articles available in the PubMed base and published after 2010.

Contrast enhanced transrectal ultrasound for the detection of prostate cancer: a randomized, double-blind trial of dutasteride pretreatment

PURPOSE

The identification of clinically significant disease is crucial for optimal treatment of prostate cancer. Selective detection of prostate cancer with increased microvessel density is possible with contrast enhanced ultrasound. Preliminary studies suggest that pretreatment with a 5α-reductase inhibitor may improve the efficiency of contrast enhanced ultrasound targeted biopsy. This study was designed to quantify prostate cancer detection with contrast enhanced ultrasound with or without short-term pretreatment with dutasteride.

MATERIALS AND METHODS

In this randomized, double-blind, placebo controlled trial of oral dutasteride pretreatment, contrast enhanced ultrasound findings were graded and used to direct targeted biopsy (up to 6 cores per prostate). A blinded 12-core systematic biopsy was subsequently performed on every subject based on standard medial and lateral sampling of each sextant.

RESULTS

Of 311 subjects who underwent randomization, 272 completed participation. Positive biopsies were obtained in 276 of 3,264 (8.5%) systematic cores and 203 of 1,237 (16.4%) targeted cores (OR 2.1, 95% CI 1.7-2.6, p <0.001). ROC analysis for the detection of all prostate cancers demonstrated an increase in diagnostic accuracy from pre-contrast imaging to contrast enhanced ultrasound (A(z) 0.60 vs 0.64, p = 0.005). For the detection of high grade cancer (Gleason score 7 or greater) ROC analysis demonstrated improved accuracy for pre-contrast imaging (A(z) 0.74) and contrast enhanced ultrasound (A(z) 0.80, p = 0.0005). For the detection of high grade cancer with greater than 50% biopsy core involvement, excellent accuracy was demonstrated with pre-contrast and contrast enhanced ultrasound, A(z) 0.83 and 0.90, respectively (p = 0.001). Pretreatment with dutasteride had no significant impact on the detection of prostate cancer (p = 0.97).

CONCLUSIONS

Contrast enhanced ultrasound targeted biopsy provides a significant benefit for the detection of high grade/high volume prostate cancer.

[New ultrasound technologies for the diagnostics of prostate cancer]

CLINICAL/METHODOLOGICAL ISSUE

Prostate cancer is the most common cancer in men. The diagnosis is based on prostate-specific antigen (PSA), digital rectal examination (DRE) and transrectal ultrasound (TRUS) guided biopsy. These techniques have considerable limitations, which result in unnecessary biopsies. Furthermore the biopsies are associated with morbidity and costs.

STANDARD RADIOLOGICAL METHODS

Standard gray-scale ultrasound has a low sensitivity and specificity for prostate cancer detection.

METHODOLOGICAL INNOVATIONS

New ultrasound technologies, including color- and power Doppler ultrasound, contrast enhanced US and real-time sonoelastography have shown to improve prostate cancer diagnosis.

PERFORMANCE

Contrast-enhanced ultrasound has shown a sensitivity of 100% (95% CI, 95%), a negative predictive value (NPV) of 99.8% and a positive predictive value (PPV) of 88.8% for prostate cancer detection. Real-time sonoelastography has shown a sensitivity of 86%, a specificity of 81% and NPV of 91% for prostate cancer diagnosis.

ACHIEVEMENTS

Most studies show that these new ultrasound modalities demonstrate a 1.5 to 2.5 times higher detection of prostate cancer per biopsy specimen compared with systematic biopsy. Multicenter studies results are at present lacking but are, however ongoing.

PRACTICAL RECOMMENDATIONS

In patients with suspected prostate cancer (elevated PSA, suspicious DRE) these new ultrasound techniques should be used. These techniques can detect prostate cancer and allow a targeted biopsy approach.

Enhanced transrectal ultrasound modalities in the diagnosis of prostate cancer

Standard grayscale transrectal ultrasound has a poor sensitivity for detection of prostate cancer. Saturation biopsy schemes have improved prostate cancer detection rates over standard template biopsy schemes, but carry additional morbidity and cost. Enhanced ultrasound modalities (EUM), including color and power Doppler, contrast-enhancement, harmonic and flash replenishment imaging, and elastography have demonstrated improved prostate cancer detection. EUM targeting areas with increased or abnormal vascularity or firmness for biopsy offer improved prostate cancer detection. EUM, detect prostate cancer more efficiently than standard ultrasound guided biopsies. These emerging technologies may potentially augment standard prostate biopsy in clinical practice.

The effect of dutasteride on the efficacy of photoselective vaporization of the prostate: results of a randomized, placebo-controlled, double-blind study (DOP trial)

OBJECTIVES

To study the effect of Dutasteride on the efficacy of GreenLight photoselective vaporization of the prostate (PV). Some investigators have suggested that 5 alpha-reductase inhibitors may interfere with PV by reducing intraprostatic blood flow. Dutasteride offers the most complete blockade of the 5 alpha-reductase inhibitors, with minimal increase in side effects.

METHODS

This is a prospective, placebo-controlled, randomized, double-blind study. A total of 59 patients were randomized to either dutasteride 0.5 mg or placebo for 3 months before and 12 months after PV. Surgical time, joules used, estimated blood loss, and ease of the procedure were compared. Other clinical end points investigated include postsurgical catheter time, hematuria, dysuria, urinary flow parameters, American Urological Association symptom score, benign prostatic hyperplasia quality of life score, prostate volume, and prostate-specific antigen level.

RESULTS

Average surgical time and joules used were 12% (P = .24) and 16% (P = .15) less, respectively, for dutasteride patients compared with placebo. Estimated blood loss was also lower in the treatment group (P = .14). However, these results were not statistically significant. Surgeon-rated ease of the procedure was comparable between the 2 groups. There were no significant differences in catheter time, dysuria, quality of life scores, or urinary flow parameters. Quality of life and urinary parameters markedly improved after PV.

CONCLUSIONS

Compared with patients randomized to placebo, patients randomized to dutasteride experienced a trend toward decreased time, joules used, and blood loss during surgery. Although we could not convincingly prove an operative benefit of treatment with dutasteride before surgery, we have demonstrated the efficacy of PV in men receiving dutasteride.

A broader role for 5ARIs in prostate disease? Existing evidence and emerging benefits

5ARIs are recommended for men who have moderate-to-severe lower urinary tract symptoms (LUTS) and benign prostatic enlargement (BPE) secondary to benign prostatic hyperplasia. Studies have confirmed the utility of combining 5ARIs with alpha-blockers; the MTOPS study showed that risk of overall clinical progression was significantly reduced after 4.5 years with combination therapy (finasteride/doxazosin) in comparison with either monotherapy, while the ongoing CombAT trial (dutasteride/tamsulosin) has for the first time shown benefit in improving symptoms for combination therapy over monotherapies within 12 months of treatment. Data also suggest roles for 5ARIs in prostate cancer. Several studies indicate that treatment with a 5ARI improves the performance of PSA testing for identifying men with prostate cancer, while the PCPT showed a significant reduction in the risk of developing prostate cancer with finasteride. However, widespread use of finasteride in this setting has been tempered by an apparent increase in high-grade disease observed in the study. The ongoing REDUCE study will provide further insight into prostate cancer prevention with 5ARIs. 5ARI-containing regimens may have utility as less aggressive treatment options for patients who only have rising PSA after definitive local therapy, and in patients with disease resistant to androgen deprivation therapy who have PSA progression. Current evidence therefore shows that 5ARIs are effective in treating LUTS/BPE and preventing disease progression, and may also have a role in the prevention of prostate cancer. The overlap between BPE and prostate cancer may allow a more unified approach to managing these conditions, with 5ARIs having a central role.

Dutasteride Prior to Contrast-Enhanced Colour Doppler Ultrasound Prostate Biopsy Increases Prostate Cancer Detection

OBJECTIVES

This study assessed the effect of premedication with dutasteride, a dual 5alpha-reductase inhibitor, on prostatic blood flow prior to prostate biopsy and its impact on prostate cancer detection.

METHODS

Thirty-six patients, aged 52-74 yr, with elevated prostate-specific antigen (PSA) levels (>or=1.25 ng/ml and free-to-total ratio of <18%) were treated with dutasteride 14 d prior to prostate biopsy. Contrast-enhanced colour Doppler (CECD) ultrasound was performed before and 7 and 14 d after dutasteride treatment. Contrast-enhanced targeted biopsies (<or=5) were performed into hypervascular areas of the peripheral zone only. Subsequently, a second investigator performed 10 systematic biopsies of the prostate in a standard spatial distribution guided by conventional grey-scale ultrasonography on a Combison 530MT unit.

RESULTS

Dutasteride reduced prostatic blood flow in benign prostatic tissue, whereas in prostate cancer areas blood flow was still observed after a 14-d course of dutasteride intake. A reduction of blood flow was observed even after 7 d. Maximum flow reduction was observed after 14 d. Twelve patients (33%) of our cohort were found to have suspicious blood flow and prostate cancer and six cancers (17%) were detected solely by targeted contrast-enhanced biopsy.

CONCLUSION

Premedication with dutasteride seems promising to improve prostate cancer detection by using CECD ultrasound.

Advances in transrectal ultrasound imaging of the prostate

Grayscale imaging of the prostate is the basic method for diagnostic evaluation and biopsy guidance. Doppler imaging may improve sensitivity for detection of prostate cancer. Microbubble contrast agents represent a major advance to more selectively demonstrate neovascular flow within the prostate. Recently, real-time elastography has been introduced to improve detection of cancer based upon changes in tissue stiffness. As diagnostic methods improve, the ultimate hope is to eliminate biopsy in patients without cancer. New ultrasound-based treatment systems, such as high-intensity focused ultrasound ablative therapy for prostate cancer, may someday allow diagnosis and treatment of prostate cancer to be completed in one sitting.

Transrectal high-intensity focused ultrasound ablation of prostate cancer: Effective treatment requiring accurate imaging

Transrectal HIFU ablation has become a reasonable option for the treatment of localized prostate cancer in non-surgical patients, with 5-year disease-free survival similar to that of radiation therapy. It is also a promising salvage therapy of local recurrence after radiation therapy. These favourable results are partly due to recent improvements in prostate cancer imaging. However, further improvements are needed in patient selection, pre-operative localization of the tumor foci, assessment of the volume treated and early detection of recurrence. A better knowledge of the factors influencing the HIFU-induced tissue destruction and a better pre-operative assessment of them by imaging techniques should improve treatment outcome. Whereas prostate HIFU ablation is currently performed under transrectal ultrasound guidance, MR guidance with real-time operative monitoring of temperature will be available in the near future. If this technique will give better targeting and more uniform tissue destruction, its cost-effectiveness will have to be carefully evaluated. Finally, a recently reported synergistic effect between HIFU ablation and chemotherapy opens possibilities for treatment in high-risk or clinically advanced tumors.

The effect of dutasteride on the peripheral and transition zones of the prostate and the value of the transition zone index in predicting treatment response

PURPOSE

We determined the effects of dutasteride on transition and peripheral zone volume, and the clinical value of the transition zone index in men with benign prostatic hyperplasia.

MATERIALS AND METHODS

A total of 2,802 men 50 years or older with diagnosed benign prostatic hyperplasia, American Urological Association symptom index score 12 or greater, total prostate volume 30 cc or greater, prostate specific antigen 1.5 ng/ml or greater and 10 ng/ml or less, and peak urinary flow rate 15 ml per second or less were randomized to receive 0.5 mg dutasteride daily or placebo for 2 years. Total prostate and transition zone volume was measured with transrectal ultrasound at baseline and 4 times during the 2-year period. Peripheral zone volume (total prostate volume minus transition zone volume) and the transition zone index (transition zone volume/total prostate volume) were calculated. Patients were stratified into tertiles according to baseline total prostate and transition zone volume, and the transition zone index.

RESULTS

At 24 months dutasteride significantly decreased total prostate volume from baseline (p <0.0001). There were similar decreases in transition and peripheral zone volume (approximately 25%). In men receiving placebo high baseline total prostate and transition zone volume, and transition zone index were associated with poor 2-year outcomes, ie a low peak urinary flow rate, high American Urological Association symptom index scores, and an increased frequency of acute urinary retention and benign prostatic hyperplasia related surgery. Improvements in outcomes with dutasteride vs placebo were greatest in men with the highest baseline total prostate and transition zone volume, and transition zone index. In men with low (30 to less than 42 cc) and intermediate (42 to less than 58 cc) baseline total prostate volume the benefits of dutasteride therapy were only significant in the intermediate (0.4 to less than 0.55) and high (0.55 to less than 1.0) transition zone index tertiles.

CONCLUSIONS

Total prostate and transition zone volume, and the transition zone index are directly related to benign prostatic hyperplasia progression. The transition zone index may add value to transition zone volume alone for predicting outcomes. Dutasteride decreased transition and peripheral zone volume equally, supporting a known therapeutic role in benign prostatic hyperplasia and a possible preventive role in prostate cancer.

The effects of the dual 5alpha-reductase inhibitor dutasteride on localized prostate cancer--results from a 4-month pre-radical prostatectomy study

BACKGROUND

As dihydrotestosterone (DHT) is the most potent androgen in the prostate, inhibition of the 5alpha-reductase isoenzymes, which convert testosterone to DHT, could be an appropriate target for the treatment of prostate cancer.

METHODS

Eighty-one men with clinically localized prostate cancer received daily dutasteride 3.5 or 0.5 mg, or no therapy for 4 months before radical prostatectomy. Histopathological assessments were conducted on prostatectomy specimens.

RESULTS

Treatment with dutasteride was associated with reductions in serum and intraprostatic DHT of >or=90%, and a decrease in total prostate and tumor volumes. No effect of dutasteride was noted on Gleason grade. Histopathological effects on benign tissue were similar but less prominent than those seen with androgen ablation, whereas there was no significant difference in cancer histology among the groups.

CONCLUSIONS

Dutasteride treatment results in similar but less marked changes compared with androgen ablation.