A brave new world in prostate imaging

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It’s one of those things men don’t like to talk about – but prostate cancer is too important to ignore. ADIA President Dr Christian Wriedt examines the diagnostic capabilities in prostate cancer imaging.

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Rated as the second most common cancer in Australian men ¹, it claims more than 3,000 lives in this country each year. This represents more than 13% of all our male-related cancer deaths.² Approximately one in seven men will be diagnosed with prostate cancer during their lifetime ³ and it is estimated that by 2020 there will be more than 25,000 newly diagnosed cases of prostate cancer in Australia.⁴
Unfortunately a patient’s journey to prostate cancer diagnosis has often been an uncomfortable and unsettling one. In the past prostate biopsies, which are a vital part of diagnosis, were performed in a semi-random fashion hoping to ‘hit’ any potential area of cancerous change. This often resulted in a missed diagnosis or in many cases underestimating the seriousness of a cancer. These challenges often led to many men putting off a potentially life-saving check-up until it was too late.
The early detection of this disease is essential because, if confined to the prostate gland, it is often curable.⁵ Thankfully, new diagnostic imaging technologies are changing the status quo, giving patients a chance to detect prostate cancer earlier and with significantly less discomfort.
The ‘Gold Standard’ of Prostate Cancer Diagnosis
In previous years diagnostic imaging had a limited ability to assist with prostate cancer diagnosis and treatment.
Dr Darren Ault, is a clinical radiologist and sub-specialist in prostate cancer imaging.
“Generally the path to diagnosis would be a digital rectal examination and a blood test to measure the level of prostate-specific antigen (PSA) in the patient’s bloodstream. Many patients with high PSA blood levels would then be offered needle biopsy of the prostate to look for evidence of cancer, despite the fact that more than 50% of patients with an elevated PSA do not have prostate cancer,” Dr Ault said.
Non-targeted needle biopsy of the prostate has several limitations in that it can miss a significant cancer or may underestimate the significance of a cancer by not sampling the most serious part of a lesion. The patient may end up with an incorrect or inaccurate diagnosis and neither the patient nor the treating doctor could be certain that a negative biopsy meant no cancer was present. On the flip side, this approach also has the risk of over-diagnosis of non-significant prostate cancer - cancer which will not cause a problem to the patient in their lifetime. Over treating this type of cancer has associated cost and risks.
There are also specific issues with different procedures.
“There are two main types of biopsies for prostate cancer – the trans-rectal ultrasound guided biopsy (TRUS) or the trans-perineal template biopsy,” Dr Ault said.
“With the trans-perineal biopsy, patients require an anaesthetic and a day stay admission. The risk of infection with TRUS biopsy can also be a source of concern for patients, particularly in the current era of multi-resistant bacteria.”
So it is no wonder that many men are put off by the prospect of going through the process of a prostate cancer diagnosis – however, new advances in diagnostic imaging are fundamentally changing the patient experience and providing better clinical outcomes.
[caption id="attachment_14844" align="alignright" width="300"] Dr Christian Wriedt
President of the Australian Diagnostic Imaging Association[/caption]
ADIA represents medical imaging practices throughout Australia, both in the community and in hospitals, and promotes ongoing development of quality practice standards so doctors and their patients can have certainty of quality, access and delivery of medical imaging services.
Visit our website www.adia.asn.au
The ‘New Standard’ in Prostate Cancer Diagnosis
Today two major advances are revolutionising prostate cancer detection and monitoring.
“Previously there wasn’t an imaging modality that could show you focal abnormalities in the prostate - now the latest technology allows that to happen,” Dr Ault said.
Multi-parametric Magnetic Resonance Imaging (ProstateMRI) is drastically changing the way prostate cancer is diagnosed. Prostate MRI combines anatomical and functional imaging to give a more complete evaluation of the prostate. This allows radiologists to alert clinicians as to the likelihood of a significant prostate cancer being present.
“Using MRI we can now produce exquisitely detailed images that allow radiologists to define suspicious lesions within the prostate and allow targeted biopsies to confirm a diagnosis of cancer. We can also be pretty confident that a normal MRI scan means that a patient does not have significant cancer.”
An Australian study into the effectiveness of Prostate MRI performed at the Wesley Hospital in Brisbane found that approximately half of the patients who presented with an elevated PSA didn’t need a biopsy once they had an MRI.
”You can effectively rule out half of the patients who would normally need to undergo a biopsy. Of the remaining 50%, if you conduct an MRI-guided biopsy, patients will only need two-to-three biopsies as opposed to over a dozen which, in theory, can drastically reduce the risk of infection,” Dr Ault said.
Another advance that is revolutionising prostate cancer monitoring and treatment is called prostate-specific membrane antigen positron emission tomography (PSMA-PET).
With most cancer patients, a radioactive agent called FDG is used when performing a PET scan. Unfortunately with prostate cancer, FDG-PET has been shown to not be accurate. Enter PSMA-PET, which uses a tracer designed specifically for prostate cancer.
“PSMA-PET is a hot topic – it provides information in addition to what we get from MRI. It’s early days but PSMA-PET seems to have a dual role: to more accurately stage people who have high risk prostate cancers and to detect recurrent prostate cancer,” Dr Ault said.
While the exact place of PSMA-PET imaging in the diagnostic pathway is still being defined it is already making a significant impact on the management of prostate cancer by increasing the accuracy in the identification of cancer within surrounding areas such as lymph nodes and bones. This is great news for patients who in the future may be able to avoid unnecessary additional surgery such as lymph node removal.
Unfortunately - despite the significant improvements to the patient experience, diagnostic accuracy and overall clinical outcome - prostate MRI, MRI-guided biopsy and PSMA-PET are not eligible for Medicare funding.
While there has been an application for prostate MRI and MRI-guided biopsy to be included in the Medicare Benefits Schedule, an outcome to this application will not be finalised for some time.⁷ Worse still, PSMA-PET is not even being considered for Medicare funding. Without Medicare funding for these services, many patients are left facing significant out of pocket expenses (in the hundreds or thousands of dollars) in order to access the best prostate cancer diagnostic techniques. It’s a cost which many Australian men simply can’t afford.
The Importance of Access
Access to these technologies must be a priority for improving Australian men’s health.The use of prostate MRI, MRI-guided biopsy and PSMA-PET is revolutionising how prostate cancer is detected and treated, providing safer and more efficient care for patients.
”At the moment you know that if you go to have your PSA test done and it comes back with an elevated result that you will probably end up having a biopsy. This discourages many men from getting a check-up,” Dr Ault said.
[caption id="attachment_14843" align="alignright" width="300"] Dr Darren Ault
Diagnostic Radiologist, Wesley Medical Imaging Brisbane[/caption]
”Advances like Prostate MRI reduce the chance of needing to have a biopsy by at least 50%. Those patients who still require a biopsy after MRI can now have a targeted procedure requiring only a couple of needles precisely aimed into the area of concern identified by the radiologist on the MRI images. Now that patients can have imaging to show whether they actually do have cancer or not, it is more likely that men will get that potentially life-saving check-up.”
The significant cost of these new radiology services is a major barrier to patients accessing what is currently the most accurate way to diagnose prostate cancer. Accurate diagnosis also means the most appropriate management options can be recommended by a patient’s treating doctor.
Appropriate Medicare funding is essential to ensure that these services are made available for all patients – not just those who can afford it.

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“Advances like Prostate MRI reduce the chance of needing to have a biopsy by at least 50%.”

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References
1 Australian Cancer Incidence and Mortality (ACIM) Books – Prostate cancer for Australia (ICD10 C61). http://www.aihw.gov.au/acim-books/ [Accessed July 2014].
2 Australian Cancer Incidence and Mortality (ACIM) Books – Prostate cancer for Australia (ICD10 C61). http://www.aihw.gov.au/acim-books/ [Accessed July 2014].
3 Australian Institute of Health and Welfare 2012. Cancer incidence projections: Australia, 2011 to 2020. Cancer Series no. 66. Cat. No. CAN 62. Canberra: AIHW
4 Ibid.
5 Gallipoli Medical Research Foundation, ‘Cyril Gilbert Testimonial Fund- prostate cancer study’ http://www.gallipoliresearch.com.au/Careers-and-Students/CGTFPProstateCancerStudy.aspx
6 Pokorny et al, (2014) ‘Prospective Study of Diagnostic Accuracy Comparing Prostate Cancer Detection by Transrectal Ultrasound–Guided Biopsy Versus Magnetic Resonance (MR) Imaging with Subsequent MR-guided Biopsy in Men Without Previous Prostate Biopsies’, European Urology 66(1), pp22-29.
7 See Department of Health http://www.msac.gov.au/internet/msac/publishing.nsf/Content/1397-public.