Use of endorectal MR imaging to predict prostate carcinoma recurrence after radical prostatectomy

Prediction of prostate cancer extracapsular extension with high spatial resolution dynamic contrast-enhanced 3-T MRI

OBJECTIVES

To assess the value of dynamic contrast-enhanced (DCE) combined with T2-weighted (T2W) endorectal coil (ERC) magnetic resonance imaging (MRI) at 3 T for determining extracapsular extension (ECE) of prostate cancer.

METHODS

In this IRB-approved study, ERC 3-T MRI of the prostate was performed in 108 patients before radical prostatectomy. T2W fast spin-echo and DCE 3D gradient echo images were acquired. The interpretations of readers with varied experience were analysed. MRI-based staging results were compared with radical prostatectomy histology. Descriptive statistics were generated for prediction of ECE and staging accuracies were determined by the area under the receiver-operating characteristic curve.

RESULTS

The overall sensitivity, specificity, positive predictive value and negative predictive value for ECE were 75 %, 92 %, 79 % and 91 %, respectively. Diagnostic accuracy for staging was 86 %, 80 % and 91 % for all readers, experienced and less experienced readers, respectively.

CONCLUSIONS

ERC 3-T MRI of the prostate combining DCE and T2W imaging is an accurate pretherapeutic staging tool for assessment of ECE in clinical practice across varying levels of reader experience.

KEY POINTS

• Endorectal coil (ERC) magnetic resonance imaging is widely used for imaging prostatic disease. • ERC 3-T MRI is reasonably accurate for local prostate cancer staging. • High diagnostic accuracy is achievable across different levels of reader experience. • MRI facilitates therapeutic decisions in patients with prostate cancer.

Incremental value of T2-weighted and diffusion-weighted MRI for prediction of biochemical recurrence after radical prostatectomy in clinically localized prostate cancer

BACKGROUND

For men with clinically localized prostate cancer and candidates to receive radical prostatectomy (RP) a main concern is a cancer recurrence after treatment. Although previous studies have demonstrated the diagnostic utility of diffusion-weighted imaging (DWI) for prostate cancer, the prognostic value of pretreatment DWI has not been investigated yet.

PURPOSE

To investigate the incremental value of MRI-based T staging using DWI and T2-weighted imaging (T2WI) as compared with the clinical parameters in prediction of biochemical recurrence (BCR) after RP for clinically localized prostate cancer.

MATERIAL AND METHODS

Sixty MR examinations, obtained before RP between April 2002 and March 2009, were retrospectively reviewed using T2WI alone, DWI alone, or T2WI + DWI for T staging according to the 2002 American Joint Committee on Cancer guidelines. The relationship between MRI stage and BCR was evaluated using Kaplan-Meier survival estimates. Multivariate analysis and receiver operating characteristics (ROC) curve analysis were used to investigate the incremental value over the standard clinical variables in prediction of BCR.

RESULTS

As of August 2009, 12 (20%) patients had BCR. Based on T2WI + DWI, both T3a (compared to OC disease) and T2 (compared to T1c) showed significantly higher BCR rates (p=0.047 and 0.025, respectively). Multivariate analysis and area under ROC curve analysis confirmed the additional value of MRI staging to the conventional clinical variables in prediction of BCR.

CONCLUSION

The combination of T2WI and DWI on performing pretreatment MRI helped predict BCR after RP in clinically localized prostate cancer.

Is endorectal coil necessary for the staging of clinically localized prostate cancer? Comparison of non-endorectal versus endorectal MR imaging

PURPOSE

The goal of this study was to compare the diagnostic use and safety of endorectal coil (ERC) MRI with those of phased-array coil MRI.

METHODS

We retrospectively included 91 consecutive patients who had undergone 1.5-T MRI with ERC or with phased-array coil MRI before radical prostatectomy at our institution. We compared 47 patients' phased-array coil MRI and 44 patients' ERC-MRI with histologic findings. We also evaluated adverse events following the MRI procedure.

RESULTS

The serum PSA levels ranged from 2.85 to 33.51 ng/mL (10.72 ± 1.9), and the median Gleason score was 7 (range 4-9). The mean interval between diagnostic prostate biopsy and staging MRI was 18.4 days (range 2-37). In assessing organ-confined disease, extracapsular extension and seminal vesicle invasion by MRI, there were no significant differences between ERC-MR group and phased-array coil MR group. The AUC values were 0.671 (95% CI 0.530-0.813) for ERC-MR and 0.657 (95% CI 0.503-0.811) for phased-array coil MR. No significant differences were found between the two groups (p = 0.24). Five patients (11.4%) developed rectal complications after ERC-MRI. However, no complications were found in phased-array coil MRI group.

CONCLUSIONS

In terms of diagnostic accuracy and comfort of patients, the use of ERC-MRI did not significantly improve the staging of prostate cancer and presented several complications. Therefore, phased-array coil MRI is a better alternative considering comorbidity.

3-T MRI with phased-array coil in local staging of prostatic cancer

RATIONALE AND OBJECTIVES

To evaluate the diagnostic accuracy of a 3-T magnetic resonance imaging (MRI) system with a phased-array coil (3T MRI) in the local staging of prostatic cancer.

MATERIALS AND METHODS

Between July 2004 and September 2007, 59 patients (mean age 66 years) with a histologic diagnosis of prostatic cancer underwent 3-T MRI with a phased-array coil. A total of 42/59 patients underwent a radical prostatectomy within 3 weeks of the MRI examination. Two radiologists with differing experience in the interpretation of prostatic imaging used a 1-5 scale score to assess extracapsular spread, seminal vesicle and neurovascular bundle infiltration, and prostatic apex involvement. The anatomopathologic examination conducted on histologic macrosections was the reference test used to evaluate the results of 3-T MRI. Interobserver reliability was assessed using the k value.

RESULTS

The sensitivity, specificity, and accuracy values obtained by the expert radiologist were 68%, 92%, and 83%, respectively, compared to 50%, 85%, and 71% for the identification of extracapsular spread and 81%, 62%, and 84% compared to 63%, 50%, and 55% for apex involvement. Interobserver reliability was good (k=0.71). Seminal vesicle infiltration was correctly identified in four of five cases and neurovascular bundle infiltration was identified in four of four cases.

CONCLUSIONS

Despite presenting diagnostic accuracy values lower than those reported in literature using 1.5-T endorectal coil MRI, the use of 3-T MRI with a phased-array coil could constitute a valid alternative to MRI techniques using endorectal coils in selected patients. Direct comparative studies between the two methods on large caseloads are required to confirm this hypothesis.

Imaging in Oncology from The University of Texas M. D. Anderson Cancer Center: Diagnosis, Staging, and Surveillance of Prostate Cancer

OBJECTIVE

The purpose of this article is to discuss the epidemiology, risk factors, and presentation of prostate cancer. After reviewing the prostate anatomy, the article will show how imaging plays an important role in establishing the diagnosis, staging, and monitoring the therapeutic response in prostate cancer, with a focus on adenocarcinomas.

CONCLUSION

Imaging studies, in the appropriate laboratory and clinical context, contribute essential information that enhances the capacity to provide individualized risk stratification, a suitable treatment strategy, and monitoring for the patient with prostate cancer.

Role of endorectal coil magnetic resonance imaging in treatment of patients with prostate cancer and in determining radical prostatectomy surgical margin status: report of a single surgeon's practice

OBJECTIVES

To evaluate the role of the combination of endorectal coil and external multicoil array magnetic resonance imaging (MRI) in the management of prostate cancer and predicting the surgical margin status in a single-surgeon practice.

METHODS

We reviewed all patients referred by a single surgeon from January 1993 to May 2002 for staging prostate MRI before selecting treatment. All MRI examinations were performed using 1.5T (Signa, GE Medical Systems) with a combination of endorectal and pelvic multicoil array. The tumor size, stage, and total gland volume on MRI, prostate-specific antigen (PSA) level, and Gleason score were all compared with the pathologic stage and diagnosis of positive surgical margins (PSMs).

RESULTS

A total of 232 patients were evaluated, of whom 110 underwent radical prostatectomy, all performed by one surgeon (group 1), and 122 did not (group 2). The results showed that MRI stage, PSA level, and age were all significantly different (P <0.001). In group 1, the results showed a high specificity (99%) and accuracy (91%) for MRI staging of T3 cancer. The postoperative follow-up (median 4.5 years) revealed that 90% of men had PSA levels of less than 0.1 ng/mL. The PSM rate was 16%. No significant difference was found on MRI between the PSM group and non-PSM group. A single tumor length greater than 1.8 cm was the cutpoint above which PSMs were found (P = 0.002).

CONCLUSIONS

The results of our study have shown that the combined use of clinical data and endorectal MRI can help optimize patient treatment and selection for surgery and, in a single surgeon's practice, lead to successful outcomes.

Tumour staging using magnetic resonance imaging in clinically localised prostate cancer: relationship to biochemical outcome after neo-adjuvant androgen deprivation and radical radiotherapy

AIMS

To evaluate the prognostic significance of magnetic resonance imaging (MRI) tumour stage in clinically localised prostate cancer.

MATERIALS AND METHODS

Between 1988 and 1999, 199 men with clinically localised prostate cancer (T -T4, N0/Nx, M0) were treated with neo-adjuvant androgen deprivation and radical radiotherapy, and were staged using MRI. Concordance between clinical tumour (cT) stage, as determined by digital rectal examination, and MRI tumour (mT) stage was assessed. Univariate and multivariate analyses using the Cox proportional hazards model were used to study the prognostic role of cT stage and mT stage in addition to established prognostic factors.

RESULTS

Of these 199 patients, 103 (52%) were upstaged on MRI, seven (3%) were downstaged, and in 89 (45%) cT and mT stages were concordant. With median follow-up of 3.8 years, 5-year freedom from prostate-specific antigen (PSA) failure was 48% (95% confidence interval (CI) 39-56%). On univariate analysis, freedom from PSA failure was associated with mT stage (P = 0.009) as well as Gleason score (P < 0.001) and initial PSA (P < 0.001), but not cT stage (P = 0.449). On multivariate analysis, Gleason score (P = 0.001), initial PSA (P < 0.001), but not mT stage (P = 0.112) remained independent determinants of freedom from PSA failure. For the subgroup of 149 patients with cT1-2 disease, mT stage was a significant predictor of increased risk of PSA failure on univariate analysis (P = 0.005), but not multivariate analysis (P = 0.19).

CONCLUSION

Freedom from PSA failure was more closely associated with mT stage than cT stage. Future studies are warranted to determine whether mT stage is an independent determinant of treatment outcome.

Complications of Prostate Cancer Treatment: Spectrum of Imaging Findings

The imaging appearances of prostate cancer are well described in the radiology literature, but little has been written about the detection and appearance of the complications of therapy for this disease. The most frequently used treatments for prostate cancer are surgical therapy (eg, radical retropubic prostatectomy, radical perineal prostatectomy), radiation therapy (eg, brachytherapy, external-beam radiation therapy, three-dimensional conformal radiation therapy, intensity-modulated radiation therapy), and cryoablative therapy, each of which may lead to complications with characteristic imaging appearances. Possible complications include lymphocele formation; injuries to the ureter, rectum, and urethra; prostatic necrosis; vesicourethral anastomotic leak and stricture; urethral stricture, necrosis, and fistula; radiation proctitis; transient bladder outlet obstruction; radiation-induced urethritis; urinary incontinence; and erectile dysfunction. With improvements in surgical techniques and advances in technology, complications of therapy for prostate cancer are decreasing but still occur with sufficient frequency to warrant familiarity on the part of radiologists. Knowledge of the diverse spectrum of these complications and their characteristic radiologic features facilitates prompt diagnosis and treatment.

Salvage radiotherapy for PSA failure after radical prostatectomy

BACKGROUND AND PURPOSE

Prostate-specific antigen (PSA) failure after radical prostatectomy is a common clinical scenario, and there is no consensus on how it should be managed. Salvage radiation to the prostatic bed is a potentially curative treatment option, and is the subject of this review. Patient selection, and the efficacy and toxicity of treatment will be discussed, and recommendations made for current practice and future studies.

METHODS

An English language MEDLINE search was performed, limited to the years 1989-2000, using the MeSH headings 'prostatic neoplasms' and 'radiotherapy'. The 660 abstracts identified were reviewed, and articles concerning patient selection for, or outcome of, post-operative radiation to the prostatic bed selected. After exclusion of articles concerning adjuvant, rather than salvage, radiation, this left a total of 22 case series, including 1062 patients for the review of treatment efficacy.

RESULTS AND CONCLUSIONS

The quality of the evidence makes it difficult to form a judgment regarding the efficacy of salvage radiation following radical prostatectomy, particularly in men with a PSA level in the range 0.01-0.2 ng/ml. Salvage radiation may be more effective given earlier rather than later. These considerations have important consequences for the interpretation of current trials of adjuvant radiation following radical prostatectomy.

The role of imaging studies and molecular markers for selecting candidates for radical prostatectomy

For the typical patient who has newly diagnosed prostate cancer, clinically organ-confined disease of moderate grade, and a PSA less than 10 ng/mL, the current role of imaging studies and molecular biomarkers is limited. Bone scans are not necessary for newly diagnosed men with a PSA less than 10 ng/mL in the absence of bone pain. Similarly, abdominal and pelvic CT scanning rarely provides any useful diagnostic or staging information when the PSA is less the 20 ng/mL and is indicated rarely. Endorectal coil MR imaging adds staging information for patients with a PSA between 10 and 20 ng/mL, a Gleason score of 7 or less, and 50% or more positive biopsies on a sextant sampling. Indium 111 capromab pendetide scanning (ProstaScint) is FDA-approved to evaluate newly diagnosed patients at high risk for metastases. These patients have a Gleason score of 7 or greater and a PSA greater than 20 ng/mL, a Gleason score of 8 to 10 regardless of the PSA value, or clinical stage T3 disease and a Gleason score of 6 or greater. RT-PCR testing of blood or bone marrow for prostate-specific or prostate cancer-specific gene expression, or "molecular staging," is a promising technique whose current use is still investigational. Much useful information may be gained by careful study of prostate needle biopsy material. Aside from current Gleason grading and the number or percentage of cores involved with cancer, no molecular biomarker is approved for clinical use. p27, p53, bcl-2, Ki-67 (MIB-1), and the assessment of neovascularity hold promise, but prospective multicenter studies are needed. In the long-term, multiple gene expression profiling of biopsy material using gene chips may revolutionize the care of patients with prostate cancer and those who elect radical prostatectomy.