USANZ Position Statement on MRI for prostate cancer
Radiological imaging of prostate cancer (PC) until recently has been limited in the local assessment of the primary tumour. However, technological advances, refinement of imaging techniques and a developing understanding of the correlation of imaging with histology has led to the increasing use of magnetic resonance imaging (MRI) in this context. The use of MRI in PC is an evolving field, and this position statement will be updated as new data emerges.
Implementation and reporting of prostate MRI
Although primarily under the jurisdiction of the RANZCR, USANZ supports the following general principles:
- Prostate MRI should be ordered for specific indications as discussed below, and only by specialists managing prostate cancer (i.e. urologists, radiation oncologists and medical oncologists) – its use in primary care is not recommended.
- Prostate MRI should be undertaken in facilities with the appropriate equipment - usually, a 3 Tesla magnet (and suitably trained staff) to provide images appropriate to base clinical decision-making.
- Imaging should encompass multiple sequences (T2, DWI, ADC and DCE with calculated b-values of 1400) according to standards well established worldwide, resulting in a multi-parametric MRI study.
- Reporting should be undertaken by radiologists with appropriate training in reporting prostate MRI. Dual reporting and clinical correlation are known to improve reporting outcomes and are encouraged.
- Reports should utilise a validated and widely accepted format – PIRADs v2 is the most widely accepted standard worldwide.
Assessment of the prostate using MRI
There is evidence to support the use of MRI to assess the prostate in a number of clinical scenarios – most prostate MRIs are currently undertaken for these indications:
- Initial assessment of the prostate in order to base a decision regarding biopsy, and to assist in targeting a lesion if visible on MRI
- Repeat assessment after initial negative biopsy (in men with ongoing suspicion of possible PC).
- Local staging of newly diagnosed PC – may be helpful in some management decisions, e.g. suitability for surgery, suitability for nerve-sparing surgery etc. Also provides staging information for pelvic lymph nodes and bony metastases involving the pelvis.
- Follow-up during active surveillance for low-risk PC – appears to strongly predict risk of progression, and may have utility in supplementing or replacing biopsy in follow-up protocols.
- Reassessment for local recurrence after primary therapy
- MRI detected abnormalities can be targeted for biopsy by 3 techniques
- Cognitively guided biopsies from the region of interest
- Fusion of MRI and US imaging to guide biopsies
- Real-time MRI-guided targeting
Cost-Utility and Cost-Effective analyses are soon to be carried out for mpMRI prostate as well as on each of these biopsy techniques by the health technology assessment group of the Federal Government.
Currently, mpMRI prostate and targeted biopsy using Fusion or “real time” in the MRI machine are not MBS funded although a joint application is currently before Government for their consideration and USANZ is advocating strongly on behalf of our patients to have this valuable test funded and to promote more widespread availability.
4 March 2016