Platinum Priority – Prostate CancerEditorial by Kate D. Linton and James W. F. Catto on pp. 76–77 of this issueCan Whole-body Magnetic Resonance Imaging with Diffusion-weighted Imaging Replace Tc 99m Bone Scanning and Computed Tomography for Single-step Detection of Metastases in Patients with High-risk Prostate Cancer?
Introduction
Less than 10% of prostate cancer (PCa) patients are diagnosed with metastases, and another 20–30% develop systemic disease after local treatment preferentially in the pelvic and lumbar lymph nodes and in the skeleton [1], [2]. Nonlymphatic visceral metastases are detected in around 10% of castration-resistant PCa (CRPC) patients [3]. Accordingly, practice guidelines recommend technetium Tc 99m bone scintigraphy (BS) and contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI) of the pelvis and abdomen to define the metastatic status in patients at high risk for metastases, that is, those with a high prostate-specific antigen (PSA) or a high Gleason score at diagnosis or a rapid PSA progression during follow-up [2], [3], [4], [5].
The diagnostic accuracy of BS is poor. Its lack of specificity frequently leads to the indication of second-line examinations, most often plain x-rays [6], [7]. Axial skeleton and whole-body MRI (WBMRI) have better sensitivity and specificity than BS [8], [9]. In addition, MRI allows objective measurement of metastases and assessment of tumour response in bone [10]. The addition of diffusion-weighted imaging (DWI) to WBMRI enables the study of extraskeletal involvement, including lymph nodes and other soft-tissue metastases, without requiring intravenous contrast agents [11], [12], [13]. Therefore, WBMRI/DWI positions itself as a potential single-step alternative to the combination of BS and CT or MRI in patients with high-risk PCa by improving the detection and measurability of metastases with the convenience of a single-step imaging technique.
This study is the first to compare prospectively the diagnostic accuracy of WBMRI/DWI against the standard combination of BS completed with targeted x-rays (BS/TXR) and CT for the detection of skeletal and visceral metastases in high-risk PCa patients.
Section snippets
Patients
Patients were included between March 2007 and March 2010 if they presented at diagnosis with a Gleason score ≥8 and/or a PSA ≥20 ng/ml or with a PSA recurrence with a PSA doubling time (DT) ≤12 mo after radical treatment or when receiving androgen-deprivation therapy (ADT). Patients underwent Tc 99m BS/TXR, contrast-enhanced thoraco-abdomino-pelvic CT, and WBMRI, including DWI, within 60 d of inclusion. The local ethics committee approved the study, and informed consent was obtained from all
Results
Patient characteristics are summarised in Table 1. One hundred patients were prospectively enrolled: 44 at initial diagnosis because of a Gleason score ≥8 and/or a PSA ≥20 ng/ml and 56 with a rapid PSA recurrence (PSA DT ≤12 mo), including 35 receiving ADT. The mean age was 69 yr of age (range: 53–88).
Discussion
Treatment guidelines universally recommend Tc 99m BS/TXR and CT or MRI to assess metastases at diagnosis in patients with a high PSA (>20 ng/ml) and/or high Gleason score (≥8) and in patients progressing after local treatment or ADT in cases of a short PSA DT [2], [3], [4], [5], [17]. Because any universal one-step substitute must be effective across all PCa stages, this study enrolled patients fulfilling one of these descriptions. Based on BVC assessment, 68% of the patients were considered
Conclusions
WBMRI is a promising, sensitive, and specific one-step technique for detecting bone metastases, enlarged lymph nodes, and visceral metastases in patients with high-risk PCa.
Acknowledgment
The authors thank N. deSouza, A. Baur, and F. Cornud for the input in the health-economic issue.
References (32)
- et al.
Prostate cancer screening decreases the absolute risk of being diagnosed with advanced prostate cancer—results from a prospective, population-based randomized controlled trial
Eur Urol
(2007) - et al.
Risk of prostate cancer-specific mortality following biochemical recurrence after radical prostatectomy
JAMA
(2005) - et al.
EAU Guidelines on prostate cancer
Eur Urol
(2008) - et al.
When to perform bone scan in patients with newly diagnosed prostate cancer: external validation of the currently available guidelines and proposal of a novel risk stratification tool
Eur Urol
(2010) Abdominal MRI advances in the detection of liver tumours and characterisation
Lancet Oncol
(2007)- et al.
New response evaluation criteria in solid tumours: revised RECIST guideline (version 1.1)
Eur J Cancer
(2009) - et al.
Potential and limitations of diffusion-weighted magnetic resonance imaging in kidney, prostate, and bladder cancer including pelvic lymph node staging: a critical analysis of the literature
Eur Urol.
(2012) - et al.
The diagnostic accuracy of CT and MRI in the staging of pelvic lymph nodes in patients with prostate cancer: a meta-analysis
Clin Radiol
(2008) - et al.
Prospective evaluation of 11C-choline positron emission tomography/computed tomography and diffusion-weighted magnetic resonance imaging for the nodal staging of prostate cancer with a high risk of lymph node metastases
Eur Urol
(2011) - et al.
Magnetic resonance imaging for the detection, localisation, and characterisation of prostate cancer: recommendations from a European consensus meeting
Eur Urol
(2011)