Does body‐coil magnetic‐resonance imaging have a role in the preoperative staging of patients with clinically localized prostate cancer?

Abstract

OBJECTIVETo investigate the accuracy and use of body‐coil magnetic resonance imaging (MRI) in the local staging of prostate cancer before radical prostatectomy (RP).PATIENTS AND METHODSFifty‐six patients undergoing RP were staged before surgery using body‐coil MRI; none was denied surgery on the basis of their scan results. All scans were reported before RP by one of three consultant radiologists and afterward by a colleague with a special interest in prostate MRI, unaware of the patients’ clinical details.RESULTSThe overall sensitivity of MRI at detecting extracapsular extension was 50% on general reporting and 72% when reported by the specialist radiologist; the respective specificities were 84% and 86%. Of the 55 patients included in the study, 18 (33%) had extracapsular disease on histological analysis. MRI was most accurate in the 17 patients at high‐risk (prostate‐specific antigen, PSA, >10 ng/mL and Gleason score ≥ 8) and eight at intermediate risk (PSA < 10 ng/mL and Gleason score 7). In the former group with specialist analysis, the sensitivity was 100%, although this decreased to 67% with general reporting. Both gave a specificity of 82%. Intermediate risk disease gave a sensitivity and specificity of 75%, irrespective of reporting method. The ability of MRI to detect extraprostatic tumour in the 30 low‐risk patients (PSA < 10 ng/mL and Gleason score 2–6) was poor; the sensitivity was 25% with general and 50% on specialist review, although both methods gave a specificity of >90%.CONCLUSIONBody‐coil MRI is sensitive and specific for identifying extracapsular extension of prostate cancer in patients with high‐ or intermediate‐risk disease. Patients at low risk frequently have microscopic extension which is not detected. Opinion from a radiologist with a special interest in prostate MRI can increase the reporting accuracy even when unaware of the patients’ clinical details.

Update on magnetic resonance imaging, ProstaScint, and novel imaging in prostate cancer*

“…Not surprisingly, the quality of interpretation is dependent on specialty training in the field, with sensitivities between 50 and 60% for those without versus 60 and 72% for those with specific training [9 ]. Interestingly, when comparing endorectal coil MRI with other clinical variables (PSA, Gleason score, clinical stage, percentage of core specimens with cancer, and percentage of cancer in all core specimens), all variables are associated with extracapsular extension on univariate analysis.…”

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

“…Allan and colleagues compared diagnostic accuracy of pelvic MRI between a "specialist" compared with a "general" radiologist and found a significant difference in accuracy. 32 Certainly, the interpretation of the MRI images is subjective and we suspect the expertise of the radiologist to be an important factor in the validity of this diagnostic test. In our series, the radiologist had a special interest in pelvic MRI and no sub-specalized training in prostatic imaging.…”

“…Allen and colleagues reported 100% specificity in detecting SV invasion, however, this study similarly had a low incidence of events (6 cases). 32 Engelbrecht and colleagues performed a meta-analysis on the local staging of prostate using MRI (with and without an endorectal coil) and found a joint maximum sensitivity and specificity of 82% for SV invasion from the summary receiver operating characteristic (ROC) curve. 33 While the performance of surface coil MRI in predicting SV invasion seems favourable, the low incidence of events in all series necessitates caution when interpreting these findings.…”

Does body‐coil magnetic‐resonance imaging have a role in the preoperative staging of patients with clinically localized prostate cancer?

“…We read this paper [1] with interest. It is clear that patients with extracapsular disease need to be identified before radical surgery, but it is also prudent to avoid unnecessary delay with unhelpful investigations between diagnosis and curative treatment.…”