The diagnostic utility of the flare phenomenon on bone scintigraphy in staging prostate cancer.

PURPOSE: Bone scintigraphy (BS) lacks sensitivity for detecting very early skeletal metastases (SM) in prostate cancer (PC) and is often limited by poor specificity. Also scintigraphic flare of SM can occur following effective treatment and mislead an early response assessment. We hypothesised that a flare reaction might amplify the signal from subclinical SM, increasing the sensitivity of BS and that the phenomenon may be specific for metastases. METHODS: We conducted a prospective study to determine the frequency of the flare phenomenon in patients with metastatic PC starting hormone therapy and to explore its utility in patients with negative staging scans but considered at high risk of SM and in those with equivocal baseline BS abnormalities. Ninety-nine patients commencing first-line hormone therapy had repeat BS at 6 weeks to score a flare reaction. RESULTS: Of 22 patients with unequivocal SM on the baseline scan, a flare occurred in 9 (41%). Of 36 high-risk localised prostate cancer patients with normal BS pre-treatment, the scan became positive for metastases at 6 weeks in 4 (11%). Of 41 patients with pre-treatment scintigraphic abnormalities of uncertain aetiology, a flare occurred in 8 cases (20%). All eight were confirmed to have SM by follow-up and imaging. Of the 33 remaining patients without a flare, 2 developed SM at 14 months and the remainder did not develop SM in a median follow-up period of 36 months. CONCLUSION: The flare phenomenon following initial hormone therapy can be used to improve both sensitivity and specificity of BS in PC.

What Burden of Prostate Cancer Can Radiologists Rule Out on Multiparametric Magnetic Resonance Imaging? A Sensitivity Analysis Based on Varying the Target Condition in Template Prostate Mapping Biopsies.

OBJECTIVE: To evaluate the minimum disease burden of prostate cancer at which multiparametric magnetic resonance imaging (MRI) optimally performs. METHODS: Between 2006 and 2008, 64 men underwent multiparametric MRI imaging (index test) followed by template prostate mapping biopsy (reference test). Three radiologists independently reported each quadrant of every prostate on a scale of 1 to 5: highly likely benign, likely benign, equivocal, likely malignant, highly likely malignant (≥3 or ≥4 was considered positive). There were 256 prostate sectors; bootstrapping adjustment was used to account for nonindependence. The target condition indicating cancer on biopsies was varied by changing the maximum cancer core length (MCCL) and total cancer core length (TCCL) within each sector from 1 mm to 10 mm. The sensitivity, specificity, and positive (PPVs) and negative predictive values (PPVs) were calculated for each MCCL and TCCL. Gleason ≤3+3 and Gleason ≥3+4 cancers were analyzed separately. RESULTS: Mean age was 62 years (range, 40-76 years), and mean prostate-specific antigen level was 8.2 µg/L (range, 2.1-43 µg/L). Fifty percent of quadrants (127 of 256) had prostate cancer, of which 65% (83 of 127) were Gleason ≤3+3. For Gleason ≤3+3, multiparametric MRI had an NPV of ≥95% at an MCCL of ≥5 mm and at a TCCL of ≥7 mm (MRI score ≥3). For Gleason ≥3+4, an NPV of ≥95% was seen at an MCCL of ≥5 mm (MRI score ≥3) and TCCL ≥6 mm. CONCLUSION: Multiparametric MRI may allow areas of the prostate which test negative to avoid biopsy. Whether multiparametric MRI can be used as a "triage" test before the first biopsy requires results from ongoing prospective validating cohort studies.

Magnetic resonance imaging for the detection, localisation, and characterisation of prostate cancer: recommendations from a European consensus meeting.

BACKGROUND: Multiparametric magnetic resonance imaging (mpMRI) may have a role in detecting clinically significant prostate cancer in men with raised serum prostate-specific antigen levels. Variations in technique and the interpretation of images have contributed to inconsistency in its reported performance characteristics. OBJECTIVE: Our aim was to make recommendations on a standardised method for the conduct, interpretation, and reporting of prostate mpMRI for prostate cancer detection and localisation. DESIGN, SETTING, AND PARTICIPANTS: A consensus meeting of 16 European prostate cancer experts was held that followed the UCLA-RAND Appropriateness Method and facilitated by an independent chair. MEASUREMENT: Before the meeting, 520 items were scored for "appropriateness" by panel members, discussed face to face, and rescored. RESULTS AND LIMITATIONS: Agreement was reached in 67% of 260 items related to imaging sequence parameters. T2-weighted, dynamic contrast-enhanced, and diffusion-weighted MRI were the key sequences incorporated into the minimum requirements. Consensus was also reached on 54% of 260 items related to image interpretation and reporting, including features of malignancy on individual sequences. A 5-point scale was agreed on for communicating the probability of malignancy, with a minimum of 16 prostatic regions of interest, to include a pictorial representation of suspicious foci. Limitations relate to consensus methodology. Dominant personalities are known to affect the opinions of the group and were countered by a neutral chairperson. CONCLUSIONS: Consensus was reached on a number of areas related to the conduct, interpretation, and reporting of mpMRI for the detection, localisation, and characterisation of prostate cancer. Before optimal dissemination of this technology, these outcomes will require formal validation in prospective trials.