Clinical Stage T1c Prostate Cancer: Evaluation with Endorectal MR Imaging and MR Spectroscopic Imaging

Abstract

Purpose:To assess the diagnostic accuracy of endorectal magnetic resonance (MR) imaging and MR spectroscopic imaging for prediction of the pathologic stage of prostate cancer and the presence of clinically nonimportant disease in patients with clinical stage T1c prostate cancer. Materials and Methods:The institutional review board approved-and waived the informed patient consent requirement for-this HIPAAcompliant study involving 158 patients (median age, 58 years; age range, 40 -76 years) who had clinical stage T1c prostate cancer, had not been treated preoperatively, and underwent combined 1.5-T endorectal MR imaging-MR spectroscopic imaging between January 2003 and March 2004 before undergoing radical prostatectomy. On the MR images and combined endorectal MR-MR spectroscopic images, two radiologists retrospectively and independently rated the likelihood of cancer in 12 prostate regions and the likelihoods of extracapsular extension (ECE), seminal vesicle invasion (SVI), and adjacent organ invasion by using a five-point scale, and they determined the probability of clinically nonimportant prostate cancer by using a four-point scale. Whole-mount step-section pathology maps were used for imaging-pathologic analysis correlation. Receiver operating characteristic curves were constructed and areas under the curves (AUCs) were estimated nonparametrically for assessment of reader accuracy. Results:At surgical-pathologic analysis, one (0.6%) patient had no cancer; 124 (78%) patients, organ-confined (stage pT2) disease; 29 (18%) patients, ECE (stage pT3a); two (1%) patients, SVI (stage pT3b); and two (1%) patients, bladder neck invasion (stage pT4). Forty-six (29%) patients had a total tumor volume of less than 0.5 cm 3 . With combined MR imaging-MR spectroscopic imaging, the two readers achieved 80% accuracy in disease staging and AUCs of 0.62 and 0.71 for the prediction of clinically nonimportant cancer. Conclusion:Clinical Note: This copy is for your personal, non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, use the Radiology Reprints form at the end of this article.I n American men, prostate cancer continues to be the most common cancer and the second leading cause of noncutaneous cancer-related mortality (1). The American Cancer Society estimated that in 2009, 192 280 new cases of prostate cancer would be diagnosed and 27 360 deaths would occur owing to this disease in the United States (1). Serum prostate-specific antigen (PSA) screening has led to a dramatic decrease in prostate cancer stage at the time of diagnosis, and stage T1c is now the most commonly diagnosed clinical stage (2).According to the TNM classification system, T1c prostate cancers are malignancies identified with needle biopsy (performed, for example, because of an elevated PSA level) that are not detectable at digital rectal examination or imaging (usually transrectal ultrasonography [US]) (3). In a study conducted by Humphrey et al (4), 78 of 100 consecutive patients who underwent rad...

The role of magnetic resonance imaging in the diagnosis and management of prostate cancer

“…Subtle signs of EPE used in standardised reporting systems include: extent of contact of the tumour with the capsule, loss of the recto-prostatic angle, bulging or irregularity of the 'pseudo-capsule' , reduced signal in the peri-prostatic fat and asymmetry of the neurovascular bundle; these signs can increase the accuracy of MRI in detecting EPE to 77%-80% [110,111]. The main limitation of MRI in T-staging is limited sensitivity, due to its inability to detect microscopic EPE.…”

Performance Characteristics of MR Imaging in the Evaluation of Clinically Low-Risk Prostate Cancer: A Prospective Study

“…Researchers in numerous studies have suggested that magnetic resonance (MR) imaging, used alone or in combination with functional or metabolic MR imaging techniques, such as MR spectroscopic imaging, can contribute valuable information to the pretreatment assessment of prostate cancer (4,(11)(12)(13)(14)(15)(16)(17)(18). Therefore, the purpose of our study was to prospectively evaluate the diagnostic performance of T2-weighted MR imaging and MR spectroscopic imaging in detecting lesions stratified by pathologic volume and Gleason score in men with clinically determined low-risk prostate cancer.…”

“…Between December 2005 and November 2009, 358 patients gave informed consent to be enrolled in a prospective Institutional Review Board-approved National Institutes of Health study investigating the use of pretreatment MR imaging and MR spectroscopic imaging for assessing clinically low-risk prostate cancer (clinical stage T1c-T2a, Gleason than expected (3,4). Conversely, many patients with clinically low-risk prostate cancer harbor clinically insignificant disease that may never require treatment (5).…”

Magnetic resonance imaging of localized prostate cancer: coming of age in the psa era

“…4), seminal vesicles, bladder wall, and local lymph nodes ( Fig. 5) (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). It should be noted, however, that MRI generally underestimates nodal involvement because it relies on nodal enlargement.…”