Purpose:To prospectively evaluate diagnostic performance of T2-weighted magnetic resonance (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.
Materials and Methods: The institutional review board approved this prospective, HIPAA-compliant study. Written informed consent was obtained from 183 men with clinically low-risk prostate cancer (cT1-cT2a, Gleason score ≤ 6 at biopsy, prostate-specific antigen [PSA] level < 10 ng/mL [10 μg/L]) undergoing MR imaging before prostatectomy. By using a scale of 1-5 (score 1, definitely no tumor; score 5, definitely tumor), two radiologists independently scored likelihood of tumor per sextant on T2-weighted images. Two spectroscopists jointly recorded locations of lesions with metabolic features consistent with tumor on MR spectroscopic images. Whole-mount step-section histopathologic analysis constituted the reference standard. Diagnostic performance at sextant level (T2-weighted imaging) and detection sensitivities (T2-weighted imaging and MR spectroscopic imaging) for lesions of 0.5 cm3or larger were calculated.
Results: For T2-weighted imaging, areas under the receiver operating characteristic curves for sextant-level detection were 0.77 (reader 1) and 0.82 (reader 2). For lesions of ≥0.5 cm3 and < 1 cm3, sensitivities were significantly lower when the lesion Gleason score was ≤ 6 (0.44 [reader 1] and 0.61 [reader 2]) rather than when the Gleason score was ≥7 (0.73, P = .02 [reader 1]; and 0.84, P = .05 [reader 2]). For lesions of ≥1 cm3, lesion Gleason score did not significantly affect sensitivity (0.83 [reader 1] and 1.00 [reader 2] for Gleason score ≤ 6 vs 0.82 and 0.92 for Gleason score ≥ 7; P ≥ .07). MR spectroscopic imaging sensitivity was low and was not significantly affected by pathologic lesion volume or Gleason score.
Conclusion: In men with clinically low-risk prostate cancer, detection of lesions of < 1 cm3 with T2-weighted imaging is significantly dependent on lesion Gleason score; detection of lesions of ≥1 cm3 is significantly better than detection of smaller lesions and is not affected by lesion Gleason score. The role of MR spectroscopic imaging alone in this population is limited.
Written by:
Vargas HA, Akin O, Shukla-Dave A, Zhang J, Zakian KL, Zheng J, Kanao K, Goldman DA, Moskowitz CS, Reuter VE, Eastham JA, Scardino PT, Hricak H. Are you the author?
Departments of Radiology, Medical Physics, Epidemiology and Biostatistics, Pathology, and Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, Room C-278, New York, NY 10065.
Reference: Radiology. 2012 Sep 5. Epub ahead of print.
doi: 10.1148/radiol.12120041
PubMed Abstract
PMID: 22952382
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