Endorectal Magnetic Resonance Imaging Research Articles

Endorectal Magnetic Resonance Imaging and Spectroscopy Are Useful for Selecting Candidates for Biopsy among Patients with Persistently Elevated Prostate Specific Antigen

Objective: To evaluate the efficacy of endorectal Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spetroscopic Imaging (MRSI) combined with total prostate-specific antigen (tPSA) and free prostate-specific antigen (fPSA) in selecting candidates for biopsy. Subjects and Methods: 246 patients with elevated tPSA (median: 7.81 ng/ml) underwent endorectal MRI and MRSI before Transrectal Ultrasound (TRUS) biopsy (10 peripheral + 2 central cores); patients with positive biopsies were treated with radical intention; those with negative biopsies were followed up and underwent MRSI before each additional biopsy if tPSA rose persistently. Mean follow-up: 27.6 months. We compared MRI, MRSI, tPSA, and fPSA with histopathology by sextant and determined the association between the Gleason score and MRI and MRSI. We determined the most accurate combination to detect prostate cancer (PCa) using receiver operating curves; we estimated the odds ratios (OR) and calculated sensitivity, specificity, and positive and negative predictive values. Results: No difference in tPSA was found between patients with and without PCa (p = 0.551). In the peripheral zone, the risk of PCa increased with MRSI grade; patients with high-grade MRSI had the greatest risk of PCa over time (OR = 328.6); the model including MRI, MRSI, tPSA, and fPSA was more accurate (Area under Curve: AUC = 95.7%) than MRI alone (AUC = 85.1%) or fPSA alone (AUC = 78.1%), but not than MRSI alone (94.5%). In the transitional zone, the model was less accurate (AUC = 84.4%). The association (p = 0.005) between MRSI and Gleason score was significant in both zones. Conclusions: MRSI is useful in patients with elevated tPSA. High-grade MRSI lesions call for repeated biopsies. Men with negative MRSI may forgo further biopsies because a significantly high Gleason lesion is very unlikely.

Diffusion-Weighted Magnetic Resonance Imaging of the Prostate

This study aimed to compare the intraclass correlation coefficients of parameters estimated with stretched exponential and biexponential diffusion models of in vivo diffusion-weighted magnetic resonance imaging (MRI) of the prostate. After the institutional review board issued a waiver of informed consent for this Health Insurance Portability and Accountability Act-compliant study, 25 patients with biopsy-proven prostate cancer underwent 3T endorectal MRI and diffusion-weighted MRI of the prostate at 10 b values (0, 45, 75, 105, 150, 225, 300, 600, 900, and 1200 s/mm). The full set of b values was collected twice within a single acquisition. Intraclass correlation coefficients were calculated for intra-acquisition variability. From the biexponential model, the quantitative parameters diffusion coefficient (D), perfusion coefficient (D*), and perfusion fraction (f) were estimated. From the stretched exponential model, the quantitative parameters Kohlrausch decay constant (DK) and alpha (α) were estimated. For the 25 patient data sets, the average intraclass correlation coefficients for DK and α were 95.8%, and 64.1%, respectively, whereas those for D, D*, and f were 84.4%, 25.3%, and 41.3%, respectively. The stretched exponential diffusion model captures the nonlinear effects of intravoxel incoherent motion in the prostate. The parameters derived from this model are more reliable and reproducible than the parameters derived from the standard, widely used biexponential diffusion/perfusion model.

EAU guidelines on prostate cancer. Part II: Treatment of advanced, relapsing, and castration-resistant prostate cancer

ObjectivesOur aim is to present a summary of the 2010 version of the European Association of Urology (EAU) guidelines on the treatment of advanced, relapsing, and castration-resistant prostate cancer (CRPC). MethodsThe working panel performed a literature review of the new data emerging from 2007 to 2010. The guidelines were updated, and the levels of evidence (LEs) and/or grades of recommendation (GR) were added to the text based on a systematic review of the literature, which included a search of online databases and bibliographic reviews. ResultsLuteinising hormone-releasing hormone (LHRH) agonists are the standard of care in metastatic prostate cancer (PCa). Although LHRH antagonists decrease testosterone without any testosterone surge, their clinical benefit remains to be determined. Complete androgen blockade has a small survival benefit of about 5%. Intermittent androgen deprivation (IAD) results in equivalent oncologic efficacy when compared with continuous androgen-deprivation therapy (ADT) in well-selected populations. In locally advanced and metastatic PCa, early ADT does not result in a significant survival advantage when compared with delayed ADT. Relapse after local therapy is defined by prostate-specific antigen (PSA) values >0.2ng/ml following radical prostatectomy (RP) and >2ng/ml above the nadir after radiation therapy (RT). Therapy for PSA relapse after RP includes salvage RT at PSA levels <0.5ng/ml and salvage RP or cryosurgical ablation of the prostate in radiation failures. Endorectal magnetic resonance imaging and 11C-choline positron emission tomography/computed tomography (CT) are of limited importance if the PSA is <2.5ng/ml; bone scans and CT can be omitted unless PSA is >20ng/ml. Follow-up after ADT should include screening for the metabolic syndrome and an analysis of PSA and testosterone levels. Treatment of castration-resistant prostate cancer (CRPC) includes second-line hormonal therapy, novel agents, and chemotherapy with docetaxel at 75mg/m2 every 3wk. Cabazitaxel as a second-line therapy for relapse after docetaxel might become a future option. Zoledronic acid and denusomab can be used in men with CRPC and osseous metastases to prevent skeletal-related complications. ConclusionThe knowledge in the field of advanced, metastatic, and CRPC is rapidly changing. These EAU guidelines on PCa summarise the most recent findings and put them into clinical practice. A full version is available at the EAU office or online at www.uroweb.org.

Localising Prostate Cancer: Comparison of Endorectal Magnetic Resonance (MR) Imaging and 3D-MR Spectroscopic Imaging with Transrectal Ultrasound-Guided Biopsy

Background: Magnetic resonance imaging (MRI) and MR spectroscopic imaging (MRSI) have been gaining acceptance as tools in the evaluation of prostate cancer. We compared the accuracy of transrectal ultrasound (TRUS)-guided biopsy and dynamic contrast-enhanced MRI combined with three-dimensional (3D) MRSI in locating prostate tumours and determined the influence of prostate weight on MRI accuracy. Patients and Methods: Between March 1999 and October 2006, 507 patients with localised prostate cancer underwent radical prostatectomy (RP) at the Jules Bordet Institute. Of these, 220 had undergone endorectal MRI (1.5 T Siemens Quantum Symphony) and 3D-MRSI prior to RP. We retrospectively reviewed data on tumour location and compared the results obtained by MRI and by TRUS-guided biopsy with those obtained on histopathology of the RP specimen. Results: Patient data were as follows: median age 62.4 years (45–74); median PSA 6.36 ng/ml (0.5–22.6); 73.6% of patients had non-palpable disease (T1c); median biopsy Gleason score 6 (3–9); median RP specimen weight 50 g (12–172); median pathological Gleason score 7 (4–10); 68.64% of patients had organ-confined (pT2) disease. Tumour localisation was correlated with RP data in a significantly higher percentage of patients when using MRI rather than TRUS-guided biopsy (47.4 vs. 36.6%, p < 0.0001). MRI was marginally superior to TRUS-guided biopsy in detecting malignancy at the prostate apex (48.3 vs. 41.9%, p = 0.0687) and somewhat better at the prostate base (46 vs. 39.1%, p = 0.0413). It was highly significantly better at mid-gland (52 vs. 41.1%, p = 0.0015) and in the transition zone (40.1 vs. 24.3%, p < 0.0001). MRI had higher sensitivity in larger (≧50 g) than smaller (<50 g) prostates (50.3 vs. 42.2%, p = 0.0017). Conclusions: MRI was superior to TRUS-guided biopsy in locating prostate tumours except at the gland apex. MRI was more accurate in larger (≧50 g) than smaller prostates.

Multiparametric 3T Prostate Magnetic Resonance Imaging to Detect Cancer: Histopathological Correlation Using Prostatectomy Specimens Processed in Customized Magnetic Resonance Imaging Based Molds

We determined the prostate cancer detection rate of multiparametric magnetic resonance imaging at 3T. Precise one-to-one histopathological correlation with magnetic resonance imaging was possible using prostate magnetic resonance imaging based custom printed specimen molds after radical prostatectomy. This institutional review board approved prospective study included 45 patients (mean age 60.2 years, range 49 to 75) with a mean prostate specific antigen of 6.37 ng/ml (range 2.3 to 23.7) who had biopsy proven prostate cancer (mean Gleason score of 6.7, range 6 to 9). Before prostatectomy all patients underwent prostate magnetic resonance imaging using endorectal and surface coils on a 3T scanner, which included triplane T2-weighted magnetic resonance imaging, apparent diffusion coefficient maps of diffusion weighted magnetic resonance imaging, dynamic contrast enhanced magnetic resonance imaging and spectroscopy. The prostate specimen was whole mount sectioned in a customized mold, allowing geometric alignment to magnetic resonance imaging. Tumors were mapped on magnetic resonance imaging and histopathology. Sensitivity, specificity, positive predictive value and negative predictive value of magnetic resonance imaging for cancer detection were calculated. In addition, the effects of tumor size and Gleason score on the sensitivity of multiparametric magnetic resonance imaging were evaluated. The positive predictive value of multiparametric magnetic resonance imaging to detect prostate cancer was 98%, 98% and 100% in the overall prostate, peripheral zone and central gland, respectively. The sensitivity of magnetic resonance imaging sequences was higher for tumors larger than 5 mm in diameter as well as for those with higher Gleason scores (greater than 7, p <0.05). Prostate magnetic resonance imaging at 3T allows for the detection of prostate cancer. A multiparametric approach increases the predictive power of magnetic resonance imaging for diagnosis. In this study accurate correlation between multiparametric magnetic resonance imaging and histopathology was obtained by the patient specific, magnetic resonance imaging based mold technique.

UP-02.230 Local Staging of Prostate Cancer; Correlation Between Endorectal Magnetic Resonance Imaging and Pathological Findings after Radical Prostatectomy in Habitual Clinical Use

We analyzed the accuracy of endorectal magnetic resonance imaging (eMRI) used in common clinical conditions (various types of machines, radiologists and radiological centers) in correlation with pathological finding after radical prostatectomy (PFRP).

Prostate Cancer: Prediction of Biochemical Failure after External-Beam Radiation Therapy—Kattan Nomogram and Endorectal MR Imaging Estimation of Tumor Volume

To determine whether magnetic resonance (MR) imaging and MR spectroscopic imaging findings can improve predictions made with the Kattan nomogram for radiation therapy. The institutional review board approved this retrospective HIPAA-compliant study. Ninety-nine men who underwent endorectal MR and MR spectroscopy before external-beam radiation therapy for prostate cancer (January 1998 to June 2007) were included. Linear predictors were calculated with input variables from the study sample and the Kattan original coefficients. The linear predictor is a single weighted value that combines information of all predictor variables in a model, where the weight of each value is its association with the outcome. Two radiologists independently reviewed all MR images to determine extent of disease; a third independent reader resolved discrepancies. Biochemical failure was defined as a serum prostate-specific antigen level of 2 ng/mL (2 μg/L) or more above nadir. Cox proportional hazard models were used to determine the probabilities of treatment failure (biochemical failure) in 5 years. One model included only the Kattan nomogram data; the other also incorporated imaging findings. The discrimination performance of all models was determined with receiver operating characteristics (ROC) curve analyses. These analyses were followed by an assessment of net risk reclassification. The areas under the ROC curve for the Kattan nomogram and the model incorporating MR imaging findings were 61.1% (95% confidence interval: 58.1%, 64.0%) and 78.0% (95% confidence interval: 75.7%, 80.4%), respectively. Comparison of performance showed that the model with imaging findings performed significantly better than did the model with clinical variables alone (P < .001). Overall, the addition of imaging findings led to an improvement in risk classification of about 28%, ranging from approximately a minimum of 16% to a maximum of 39%, depending on the risk change considered important. MR imaging data improve the prediction of biochemical failure with the Kattan nomogram after external-beam radiation therapy for prostate cancer. The number needed to image to improve the prediction of biochemical failure in one patient ranged from three to six.

Guía de la EAU sobre el cáncer de próstata. Parte II: tratamiento del cáncer de próstata avanzado, recidivante y resistente a la castración

Objectives Our aim is to present a summary of the 2010 version of the European Association of Urology (EAU) guidelines on the treatment of advanced, relapsing, and castration-resistant prostate cancer (CRPC). Methods The working panel performed a literature review of the new data emerging from 2007 to 2010. The guidelines were updated, and the levels of evidence (LEs) and/or grades of recommendation (GR) were added to the text based on a systematic review of the literature, which included a search of online databases and bibliographic reviews. Results Luteinising hormone-releasing hormone (LHRH) agonists are the standard of care in metastatic prostate cancer (PCa). Although LHRH antagonists decrease testosterone without any testosterone surge, their clinical benefit remains to be determined. Complete androgen blockade has a small survival benefit of about 5%. Intermittent androgen deprivation (IAD) results in equivalent oncologic efficacy when compared with continuous androgen-deprivation therapy (ADT) in well-selected populations. In locally advanced and metastatic PCa, early ADT does not result in a significant survival advantage when compared with delayed ADT. Relapse after local therapy is defined by prostate-specific antigen (PSA) values > 0.2 ng/ml following radical prostatectomy (RP) and > 2 ng/ml above the nadir after radiation therapy (RT). Therapy for PSA relapse after RP includes salvage RT at PSA levels < 0.5 ng/ml and salvage RP or cryosurgical ablation of the prostate in radiation failures. Endorectal magnetic resonance imaging and 11C-choline positron emission tomography/computed tomography (CT) are of limited importance if the PSA is < 2.5 ng/ml; bone scans and CT can be omitted unless PSA is >20 ng/ml. Follow-up after ADT should include screening for the metabolic syndrome and an analysis of PSA and testosterone levels. Treatment of castration-resistant prostate cancer (CRPC) includes second-line hormonal therapy, novel agents, and chemotherapy with docetaxel at 75 mg/m 2 every 3 wk. Cabazitaxel as a second-line therapy for relapse after docetaxel might become a future option. Zoledronic acid and denusomab can be used in men with CRPC and osseous metastases to prevent skeletal-related complications. Conclusion The knowledge in the field of advanced, metastatic, and CRPC is rapidly changing. These EAU guidelines on PCa summarise the most recent findings and put them into clinical practice. A full version is available at the EAU office or online at www.uroweb.org.

Comparison of Real-time Sonoelastography With T2-Weighted Endorectal Magnetic Resonance Imaging for Prostate Cancer Detection

The purpose of this study was to compare the value of real-time sonoelastography with T2-weighted endorectal magnetic resonance imaging (MRI) for prostate cancer detection. Thirty-three patients with an elevated prostate-specific antigen level were investigated with real-time sonoelastography and T2-weighted endorectal MRI for prostate cancer diagnosis before systematic prostate biopsy. Real-time sonoelastography was performed to assess prostate tissue elasticity, and hard areas were considered suspicious for prostate cancer. Low-signal intensity nodules on T2-weighted endorectal MRI were considered suspicious for prostate cancer. Imaging findings were assigned to 6 areas of the peripheral zone (sextants), and their cancer detection rates were compared. Overall, prostate cancer was detected in 13 of 33 patients (39.4%). Both real-time sonoelastography and T2-weighted endorectal MRI detected 11 cancer-positive patients (84.6%). Real-time sonoelastography showed 27 suspicious lesions in 198 sextants, and 15 (55.6%) were cancer positive. T2-weighted endorectal MRI showed 31 suspicious lesions in 198 sextants, and 13 (40.6%) were cancer positive. These findings resulted in sensitivity rates and negative predictive values per patient of 84.6% and 86.7%, respectively, for sonoelastography and 84.6% and 83.3% for MRI. The per-sextant analysis showed sensitivity rates and negative predictive values of 57.7% and 93.6% for sonoelastography and 50.0% and 92.2% for MRI. Real-time sonoelastography showed comparable results as T2-weighted endorectal MRI for prostate cancer detection.

Endorectal MRI after radiation therapy: Questioning the sextant analysis

To evaluate whether the information gained by three coregistration systems (sextant, hemi-prostate, and whole gland) differs significantly, suggesting that one approach should be routinely favored over the others. Despite its known limitations, sextant is the generally accepted standard for magnetic resonance imaging (MRI) and biopsy coregistration; nevertheless, depending on the magnitude of localization errors, other options may be adequate. Institutional Review Board approval was obtained and the study was Health Insurance Portability and Accountability Act (HIPAA)-compliant. We identified 70 patients who underwent 1.5 T endorectal MRI of the prostate between 1999 and 2008 after external beam radiotherapy for prostate cancer. A single reader reviewed all T2-weighted images for the presence or absence of tumor. The performance of each approach was quantified using receiver operating characteristic (ROC) curve analysis. Transrectal ultrasound-guided sextant biopsies were used as a standard of reference. The areas under the ROC curve indicating accuracy for each MRI approach were 0.63 (sextant), 0.68 (hemi-prostate), and 0.71 (whole gland). There was no statistically significant difference among these approaches. As expected, the point estimate was higher for the whole-gland approach, but not significantly. Reliable assessment of locally recurrent prostate cancer after external beam radiotherapy by endorectal MRI may be made using a sextant, hemi-prostate, or whole gland approach. The option for one or another approach should not be solely based on estimations of imaging accuracy, but on the purpose of the procedure.

Oncologic Imaging: A Guiding Hand of Personalized Cancer Care

Our discipline is in a remarkably strong position to guide and advance the practice of medicine in the 21st century.

Diffusion-weighted Endorectal MR Imaging at 3 T for Prostate Cancer: Tumor Detection and Assessment of Aggressiveness

To assess the incremental value of diffusion-weighted (DW) magnetic resonance (MR) imaging over T2-weighted MR imaging at 3 T for prostate cancer detection and to investigate the use of the apparent diffusion coefficient (ADC) to characterize tumor aggressiveness, with whole-mount step-section pathologic analysis as the reference standard. The Internal Review Board approved this HIPAA-compliant retrospective study and waived informed consent. Fifty-one patients with prostate cancer (median age, 58 years; range, 46-74 years) underwent T2-weighted MR imaging and DW MR imaging (b values: 0 and 700 sec/mm(2) [n = 20] or 0 and 1000 sec/mm(2) [n = 31]) followed by prostatectomy. The prostate was divided into 12 regions; two readers provided a score for each region according to their level of suspicion for the presence of cancer on a five-point scale, first using T2-weighted MR imaging alone and then using T2-weighted MR imaging and the ADC map in conjunction. Areas under the receiver operating characteristic curve (AUCs) were estimated to evaluate performance. Generalized estimating equations were used to test the ADC difference between benign and malignant prostate regions and the association between ADCs and tumor Gleason scores. For tumor detection, the AUCs for readers 1 and 2 were 0.79 and 0.76, respectively, for T2-weighted MR imaging and 0.79 and 0.78, respectively, for T2-weighted MR imaging plus the ADC map. Mean ADCs for both cancerous and healthy prostatic regions were lower when DW MR imaging was performed with a b value of 1000 sec/mm(2) rather than 700 sec/mm(2). Regardless of the b value used, there was a significant difference in the mean ADC between malignant and benign prostate regions. A lower mean ADC was significantly associated with a higher tumor Gleason score (mean ADCs of [1.21, 1.10, 0.87, and 0.69] × 10(-3) mm(2)/sec were associated with Gleason score of 3 + 3, 3 + 4, 4 + 3, and 8 or higher, respectively; P = .017). Combined DW and T2-weighted MR imaging had similar performance to T2-weighted MR imaging alone for tumor detection; however, DW MR imaging provided additional quantitative information that significantly correlated with prostate cancer aggressiveness.

A pilot study of endorectal magnetic resonance imaging and magnetic resonance spectroscopic imaging changes with dutasteride in patients with low risk prostate cancer

•To evaluate the effects of dutasteride on treatment-naïve prostate cancer in men using serial magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) in this pilot study. •This investigator-initiated prospective single-arm study was approved by the institutional committee on human research ethics board. •The target accrual was 10 patients. Newly diagnosed prostate cancer patients with low risk disease either with symptomatic benign prostatic hypertrophy or deemed to require pre-brachytherapy androgen suppression therapy were eligible. In the latter group, dutasteride was used to achieve cytoreduction. •All patients received 6 months of dutasteride 3.5 mg daily and underwent baseline blood work, health-related quality of life indices and MRI/MRSI, which were repeated at 1, 3 and 6 months. •MRSI spectra were examined and scored as healthy or cancerous. The change in cancerous volumes over time was evaluated. •Of the 10 patients enrolled, nine patients completed the entire study. One patient withdrew after 3 months because of drug-related toxicity. •Because a significant decrease in citrate and polyamines on MRSI spectra was noted at 1 month compared with baseline, healthy tissue appeared to be more like cancer and thus created a false impression that the cancer had grown after 1 month. To reduce this bias, comparisons were made between the 1-month and 6-month scans. •The median MR cancer volumes at 6 months and 3 months were 100% and 101% of the 1-month value, respectively. Three of the nine patients had a 30-45% decrease in cancer volume at 6 months relative to 1-month measures. Of the others, two had no change in cancer volume and four had an increase (range 65-167% of the 1-month value). •The median cancer volume (range) at baseline was only 0.5 (0.1-5.6) mL. •The inclusion of only men with low volume disease may have limited our ability to accurately assess response rates after dutasteride due to the background effects on normal prostate metabolism. Despite this, one-third of patients had a 30-45% reduction in cancer volume at 6 months. •Future studies including men with larger volume disease may enable estimates of response rates to be made more accurately.

Inapparent Tumor on Endorectal Multimodality Magnetic Resonance Imaging of Prostate: Should We Perform a Biopsy?

To examine whether one could spare patients with a clinical suspicion of prostate cancer (PCa) but inapparent tumor on multimodality endorectal magnetic resonance imaging (e-MRI) of the prostate from undergoing prostate biopsy. A total of 109 patients with a clinical suspicion of PCa underwent conventional and functional e-MRI of the prostate and subsequently prostate biopsy. The inclusion criteria were prostate-specific antigen level>4 ng/mL or a suspicious finding on digital rectal examination. The images were interpreted by a highly experienced radiologist and were considered negative for PCa in all cases. Regardless of the negative findings, all patients underwent an 18-core prostate biopsy. Functional e-MRI included contrast-enhanced e-MRI and diffusion-weighted imaging. The examinations were performed on a closed 1.0-T system combined with an endorectal body phased-array coil. The clinicopathologic parameters of the patients included age, prostate-specific antigen level, digital rectal examination findings, PCa detection rate, clinically significant PCa detection rate, high-grade PCa detection rate, and e-MRI specificity. The median age of the patients was 67.4 years, and the median prostate-specific antigen level was 12.9 ng/mL. The digital rectal examination findings were positive in 42 patients (38.5%) and negative in 67 patients (61.5%). Overall, PCa was detected in 19.2% of patients, with 47.6% cases defined as clinically significant and 38.1% as high grade. Overall, the e-MRI specificity was 80.8%. The results of our study have shown that the absence of tumor on e-MRI scans of patients with a clinical suspicion of PCa does not rule out the probability of clinically significant and high-grade PCa, making prostate biopsy mandatory for these patients as well.

Semi‐automatic deformable registration of prostate MR images to pathological slices

To present a semi-automatic deformable registration algorithm for co-registering T2-weighted (T2w) images of the prostate with whole-mount pathological sections of prostatectomy specimens. Twenty-four patients underwent 1.5 Tesla (T) endorectal MR imaging before radical prostatectomy with whole-mount step-section pathologic analysis of surgical specimens. For each patient, the T2w imaging containing the largest area of tumor was manually matched with the corresponding pathologic slice. The prostate was co-registered using a free-form deformation (FFD) algorithm based on B-splines. Registration quality was assessed through differences between prostate diameters measured in right-left (RL) and anteroposterior (AP) directions on T2w images and pathologic slices and calculation of the Dice similarity coefficient, D, for the whole prostate (WP), the peripheral zone (PZ) and the transition zone (TZ). The mean differences in diameters measured on pathology and MR imaging in the RL direction and the AP direction were 0.49 cm and -0.63 cm, respectively, before registration and 0.10 cm and -0.11 cm, respectively, after registration. The mean D values for the WP, PZ and TZ, were 0.76, 0.65, and 0.77, respectively, before registration and increased to 0.91, 0.76, and 0.85, respectively, after registration. The improvements in D were significant for all three tissues (P < 0.001 for all). The proposed semi-automatic method enabled successful co-registration of anatomical prostate MR images to pathologic slices.

An Exploratory Study of Endorectal Magnetic Resonance Imaging and Spectroscopy of the Prostate as Preoperative Predictive Biomarkers of Biochemical Relapse After Radical Prostatectomy

Radical prostatectomy has significant side effects. Preoperative information predicting its long-term outcome would be valuable to patients and physicians. We determined whether pretreatment endorectal magnetic resonance imaging/magnetic resonance spectroscopic imaging predicts biochemical recurrence after radical prostatectomy. Of 202 patients who underwent endorectal magnetic resonance imaging/magnetic resonance spectroscopic imaging from January 2000 to December 2002 before radical prostatectomy 130 satisfied study inclusion criteria and were included in analysis. We compared imaging factors with potential predictive capability to biochemical recurrence data, including magnetic resonance imaging risk score based on local disease extent and magnetic resonance spectroscopic imaging index lesion characteristics, such as the number of voxels and degree of metabolic abnormality (magnetic resonance spectroscopic imaging grade). We evaluated associations of these imaging variables with time to biochemical recurrence by Cox proportional hazards regression adjusted for known predictors of biochemical recurrence, such as stage, grade and prostate specific antigen. At a median 68-month followup there were 26 biochemical failures. Risk score, lesion volume and high grade voxels each correlated with time to biochemical recurrence. In a model combining clinical parameters risk score, lesion volume and at least 1 high grade voxel the magnetic resonance spectroscopic imaging variables remained significant but the magnetic resonance imaging score dropped out. Index lesion volume on magnetic resonance spectroscopic imaging and high grade magnetic resonance spectroscopic imaging voxels correlate with time to biochemical recurrence after radical prostatectomy even when adjusted for clinical data. Results suggest the preoperative predictive usefulness of endorectal magnetic resonance imaging/magnetic resonance spectroscopic imaging in patients considering radical prostatectomy.

Unnecessary Imaging for the Staging of Low-risk Prostate Cancer Is Common

To quantify the rate of overuse of preoperative imaging procedures in a referral cohort of low-risk patients. International evidence-based best practice guidelines discourage routine imaging for staging purposes in low-risk patients with newly diagnosed prostate cancer. An institutional database comprised of all patients undergoing robotic-assisted laparoscopic prostatectomy was queried for "low-risk" patients between May 2005 and January 2010. "Low-risk" was defined by the most inclusive criteria for imaging recommendations: prostate-specific antigen ≤10 ng/mL and Gleason score ≤6. We defined staging imaging as a bone scan, computed tomography (CT) of the pelvis or endorectal magnetic resonance imaging performed after the diagnosis of prostate cancer and before prostatectomy for the indication of "prostate cancer." Six-hundred seventy-seven patients were identified as having low-risk disease and comprised our study population. Of the 677 patients identified as low risk, 328 (48%) underwent at least one preoperative imaging procedure despite the guideline recommendations. Two-hundred two of 677 (30%) patients were administered at least 2 of the 3 modalities, and 18/677 (3%) patients received all 3 imaging examinations before prostatectomy. Suspicious results from the CT (7/265%, 2.7%) or bone scan (21/241%, 8.7%) resulted in 27 patients undergoing additional radiographic imaging, none of which resulted in suspicious lesions requiring intervention or biopsy. Despite international evidence-based guidelines for the staging of newly diagnosed prostate cancer patients, many urologists continue to refer low-risk patients for unnecessary imaging studies. This may place the patient at increased risk from radiation or contrast exposure and places an unnecessary financial burden on the patient and health care system.

Prostate Cancer: Differentiation of Central Gland Cancer from Benign Prostatic Hyperplasia by Using Diffusion-weighted and Dynamic Contrast-enhanced MR Imaging

To analyze the diffusion and perfusion parameters of central gland (CG) prostate cancer, stromal hyperplasia (SH), and glandular hyperplasia (GH) and to determine the role of these parameters in the differentiation of CG cancer from benign CG hyperplasia. In this institutional review board-approved (with waiver of informed consent), HIPAA-compliant study, 38 foci of carcinoma, 38 SH nodules, and 38 GH nodules in the CG were analyzed in 49 patients (26 with CG carcinoma) who underwent preoperative endorectal magnetic resonance (MR) imaging and radical prostatectomy. All carcinomas and hyperplastic foci on MR images were localized on the basis of histopathologic correlation. The apparent diffusion coefficient (ADC), the contrast agent transfer rate between blood and tissue (K(trans)), and extravascular extracellular fractional volume values for all carcinoma, SH, and GH foci were calculated. The mean, standard deviation, 95% confidence interval (CI), and range of each parameter were calculated. Receiver operating characteristic (ROC) and multivariate logistic regression analyses were performed for differentiation of CG cancer from SH and GH foci. The average ADCs (× 10(-3) mm(2)/sec) were 1.05 (95% CI: 0.97, 1.11), 1.27 (95% CI: 1.20, 1.33), and 1.73 (95% CI: 1.64, 1.83), respectively, in CG carcinoma, SH foci, and GH foci and differed significantly, yielding areas under the ROC curve (AUCs) of 0.99 and 0.78, respectively, for differentiation of carcinoma from GH and SH. Perfusion parameters were similar in CG carcinomas and SH foci, with K(trans) yielding the greatest AUCs (0.75 and 0.58, respectively). Adding K(trans) to ADC in ROC analysis to differentiate CG carcinoma from SH increased sensitivity from 38% to 57% at 90% specificity without noticeably increasing the AUC (0.79). ADCs differ significantly between CG carcinoma, SH, and GH, and the use of them can improve the differentiation of CG cancer from SH and GH. Combining K(trans) with ADC can potentially improve the detection of CG cancer. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100021/-/DC1.

Endorectal magnetic resonance imaging has limited clinical ability to preoperatively predict pT3 prostate cancer

• To assess the clinical value of preoperative knowledge of the presence of extracapsular extension (ECE) or seminal vesicle invasion (SVI) in the planning for prostatectomy. • An institutional database of 1161 robotic-assisted laparoscopic prostatectomies (RALP) performed by a single surgeon (D.B.S.) was queried for those who underwent endorectal coil magnetic resonance imaging (erMRI) before robotic-assisted laparoscopic prostatectomy. • erMRI reports were dichotomized into positive or negative and compared with the final histopathology. The erMRIs performed at academic centres were compared with those performed in non-academic settings. • A sub-group of high-risk patients was also analyzed for erMRI accuracy. • The 179 patients who underwent erMRI had significantly worse disease compared to the 982 patients without imaging. Of the 110 patients with histopathologically organ-confined disease, 81 (74%) were correctly diagnosed as such on erMRI, whereas 29 (26%) were felt to have cT3 disease and constituted false-positives. Among the 69 patients with pT3 disease, erMRI correctly predicted 30 (43%), whereas 39 (57%) were incorrectly considered organ-confined. • The overall sensitivity and specificity for diagnosing pT3 disease was 43% and 73%. • When stratified by pT3a and pT3b, the sensitivity and specificity of erMRI to accurately diagnose ECE is 33% and 81%, respectively. In evaluating SVI, erMRI has a sensitivity and specificity of 33% and 89%, respectively. The positive predictive value of erMRI to assess for ECE and SVI is 50% in both, with a negative predictive value of 61% and 63%, respectively. • erMRIs performed at academic centres compared to non-academic locations demonstrated similar rates of sensitivity at 67% vs 77% and specificity at 39% vs 54%, respectively (P = 0.33). • In the setting of the present study, which was designed to be more reflective of current practice patterns in the USA, erMRI has limited clinical value in preoperatively detecting ECE and SVI. • The accuracy of detecting T3 disease did not improve in academic centres or in high-risk patients.

Diagnostic accuracy of surface coil magnetic resonance imaging at 1.5 T for local staging of elevated risk prostate cancer

Preoperative prostate cancer stage predicts prognosis and affects treatment decisions. The purpose of this study was to estimate the sensitivity and specificity of surface coil magnetic resonance imaging (MRI) for prostate cancer stage using surgical pathologic data as the reference standard. High-risk patients (>/=cT3 or PSA >/=20 ng/mL or Gleason >/=8) and selected intermediate-risk patients (clinically bulky disease on exam or biopsy, cT2b/c, or Gleason 7 with >/=3 of 5 biopsy cores positive in a lobe) routinely received a pelvic MRI at our institution. The images of identified patients were reviewed by one radiologist who was blinded to clinical information. The radiologist reported presence or absence of tumour within each lobe of the prostate. Extraprostatic extension (EPE), seminal vesicle (SV) invasion and pelvic lymph node (PLN) metastasis were also reported. Radiological findings were compared with prostatectomy pathology reports. During the study period, about 320 radical prostatectomies were performed. Of these, 32 had a preoperative surface coil pelvic MRI adequate for analysis. Pathologically, 53 of 64 (82.8%) prostate lobes contained tumour, 17 (26.6%) lobes had associated EPE, 12 (18.8%) had SV involvement and 7 (10.9%) sets of PLNs contained cancer. Magnetic resonance imaging sensitivity and specificity were, respectively, 94.3% and 81.8% for tumour location, 82.4% and 87.2% for EPE, 83.3% and 92.3% for SV invasion and 71.4% and 94.7% for PLN involvement. Surface coil MRI accurately stages many prostate cancer patients with elevated risk of extraprostatic disease. This mode of imaging may be reasonable at centres that do not have endorectal coil MRI.