Robotic Transperineal Prostatic Fusion Biopsy
I am proud to introduce Queensland’s first robotic transperineal prostatic biopsy system – the Mona Lisa BioBot. The service is provided in conjunction with The Sunshine Coast Private Hospital, Buderim.
Robotic targeting provides unsurpassed accuracy during transperineal biopsy of MRI identified prostatic lesions, with extremely low infection risk. The Mona Lisa BioBot imports CAD segmented MRI images and targets, then fuses these with real-time 3-D ultrasound to give accurate lesion positioning. After biopsy planning, the robotic system then gives precise control of the direction and depth of each biopsy core. Biopsies are taken through only two transperineal puncture sites, dramatically reducing the incidence of infective complica ons compared to classical transrectal biopsy.
MRI-informed robotic targeted transperineal biopsy provides an optimised diagnostic pathway, with more accurate diagnosis and patient risk-stratification. Better diagnosis, grading and staging allows for better treatment choices for patients with clinically significant prostate cancer, while reducing overdiagnosis and overtreatment of insignificant disease.
What about MRI Prostate?
The prostate cancer diagnostics service is supported by world-class Radiology. Sunshine Coast Medical Imaging works in conjunc on with Wesley Medical Imaging - one of the highest volume units in the world. The group boasts a highly experienced team of radiologists that introduced advanced prostatic MRI to Australia, and were involved in a world-first clinical trial for prostate cancer diagnosis. This published trial has become one of the highest cited papers in all urological literature in the last 2 years.
MRI is a game-changer in prostate cancer diagnostics, with better detection of significant cancers. When combined with alterations in biopsy techniques, it may also reduce identification of insignificant cancers. Mul -parametric MRI of the prostate (mpMRI) is very difficult to perform and interpret correctly. It requires specialised MRI techniques, specific radiologist training, and urologist clinical input. Even in the best of hands, 10-20% of significant prostate cancers are still MRI invisible. Given the potential for misinterpretation and misunderstanding of this important diagnostic aid, the general radiological and urological view is to refer any patient of concern to a Urologist before performing prostate MRI.
Why Offer PSA Testing?
Level 1 evidence shows PSA tes ng saves lives for men 50-69 (Consensus statement, Prostate Cancer World Congress, Melbourne, 2013), with numbers needed to screen and treat per life saved be er than for breast or colon cancer. The main concerns with PSA testing relate to potential downsides of overdiagnosis and overtreatment of insignificant cancer. Recent advances in MRI and biopsy diagnostics, improvements in radical therapies, and surveillance of low-risk cases are working to mitigate these issues. It is important to discuss the pros and cons of reduced death rates and rates of presenta ons with metastatic disease vs. potential overdiagnosis and overtreatment with patients before embarking on PSA testing.
When to start? 50 years of age. High-risk patients 40-45yo. Men up to 70 years of age are those most likely to benefit from early detection.
HIGH RISK - Family history prostate cancer (especially if <60yo), BRACA or Lynch Syndrome, African ancestry.
When to refer? PSA >3 (PSA >2 in 40’s) (NCCN Guidelines Version 1.2014 Prostate Cancer Early Detec on). Given the complexities and the pros and cons of prostate cancer diagnostics, Urologists are then best placed to further assess and advise pa ents whether further evaluation is indicated.
Prostate multi-parametric MRI – an update
The goal of the Urological community is to better find and characterise important prostate cancers (reduced under-diagnosis and under-treatment), while also finding less focal low-grade cancer (reducing over-diagnosis and potential over-treatment). Prostatic multi-parametric MRI (mpMRI) is a game-changer in the diagnostic pathway of significant prostate cancer, as it can visualise many significant prostate cancers, while tending to not see small-volume low-grade disease. Nevertheless, prostate MRI performance and interpretation is fraught with many pitfalls, and its role in the prostate cancer diagnostic pathway is yet to be fully defined.
Historically, prostate cancer has been poorly visualised on imaging. Therefore, ultrasound-guided biopsies follow a template-mapping pattern, which is essentially random sampling. Accordingly, clinically significant disease may be missed or under-graded, while clinically insignificant small volume, low-grade disease may be inadvertently detected.
Attempts to utilise just T2 MRI imaging of the prostate proved fruitless. Recognition of the value of the simultaneous assessment and scoring of other MRI parameters (“multi-parametric”) was a breakthrough.
T2 imaging shows the prostatic anatomy nicely, but is not specific and so not particularly useful in the peripheral zone where most prostate cancers occur, as cancer is indistinguishable from many benign changes on T2 images in this area. It is however useful in identifying infiltrating lesions in the transition zone i.e. in the central adenoma.
Diffusion-weighted imaging (DWI) looks at the molecular movement of water molecules in tissues – the “harder” the tissue, the less the water can vibrate. It is analogous to an MRI “finger” feeling a lump that is often imperceptible to a human finger. This is very useful in the peripheral zone, but not so useful with the central nodular prostatic adenoma. Dynamic contrast enhancement (DCE) assesses vascularity - prostate cancer often demonstrates early contrast enhancement with rapid washout. This is useful in stratifying equivocal findings on T2 and DWI. An overall score is given on a scale from the likelihood of significant cancer being “highly unlikely” to “highly likely”.
Both performance of, and interpretation of prostate mpMRI has a steep learning curve. It must be performed on good quality machines with properly set-up software and sequencing protocols. Even with good quality imaging, radiologists usually need to read 200 supervised cases before considered competent, with ongoing co-reading recommended, still with access to a reference centre of excellence. Therefore it is important that mpMRI is performed at an experienced centre, or one with supervised up-skilling programme with quality assurance protocols in place. In addition, I still personally co-read every mpMRI I order with the radiologists involved, and review relevant cases at second-weekly Uro-Radiology team meetings with a specific focus on prostate cancer and prostate mpMRI.
From a diagnostic perspective I currently offer mpMRI to any man for whom I am recommending a prostate biopsy based on his PSA parameters, prostate examination findings and clinical context. In those considered at relatively low risk where observation without biopsy is being considered, I also offer it to double-check there is nothing obvious being missed. A negative mpMRI in a low-risk patient may then act as a useful baseline for future reference.
mpMRI may at times influence the decision as to whether to biopsy or not. A given patient’s pre-MRI probability of having prostate cancer (as judged by multiple factors including PSA, PSA velocity, PSA density, family history, and rectal examination) affects the likely significance of a given result. A negative mpMRI does not mean the patient definitely does not have significant prostate cancer. mpMRI’s main role in the diagnostic process is to influence how biopsy is performed. A positive mpMRI informs which areas are to be particularly targeted at biopsy, with less chance of missing a significant tumour than mapping biopsy alone.
Conclusion: Prostate mpMRI is emerging as a promising tool in prostate cancer diagnosis. Its exact role is yet to be clearly defined, though it may well become a standard of care. As yet, mpMRI prostate does not have a Medicare rebate and typically costs around $550. There is an ongoing MSAC application with the federal government so that prostate mpMRI may become rebatable.
Quality mpMRI prostate is hard to do, and even harder to interpret. Even in the best of hands, a negative mpMRI can still miss significant tumours. Given the potential for misinterpretation and misunderstanding of this emerging diagnostic aid, the general radiological and urological view is to refer any patient of concern to a Urologist for any decision about mpMRI.
Dr Tony Gianduzzo 29.7.15
Level 1 evidence shows PSA testing saves lives, with numbers needed to screen and treat per life saved better than for breast or colon cancer. Carefully done, it probably halves death rates. The issues with PSA testing relate to downsides of potential over-diagnosis and overtreatment of insignificant cancer. Recent advances in MRI diagnostics, improvements in radical therapies, and surveillance of low-risk cases are gradually mitigating these issues. It is important to discuss the pros and cons of reduced death rates vs. potential over-diagnosis and overtreatment with patients before embarking on PSA testing.
Men 40-70 years of age are those most likely to benefit from early detection.
WHEN TO START
FIRST PSA at 40-45yo to risk-stratify (i.e. before BPH develops to confound the result)
½ of all men dying of prostate cancer had a baseline PSA >1.5 in early 40’s. PSA <0.6 at this age confers a very low risk.
Recommendations vary. The following is my personal interpretation of “smart screening”.
PSA <1.0 - once every 5 years
PSA >1.0 or high risk once/ year (watch especially carefully if >1.5)
PSA <1.0 - once every 5 years
PSA 1.0 to 2.0 - every 2-3 years
PSA >2.0 or high risk - once/ year
HIGH RISK - Family History Ca Prostate (especially if <60yo), BRACA, or Lynch Syndrome
nb Lower urinary tract symptoms are not associated with early Ca Prostate (but can be with advanced disease)
WHEN TO REFER?
- Recommendations vary.
a) 40’s - PSA >2
>50 - PSA >3 (more aggressive approach)
b) use lab reference ranges (less aggressive approach)
PSA’s can bounce quite a bit – if there is an odd jump in a PSA (and there is no hard prostatic nodule), a repeat reading 6-8 weeks later is reasonable. Even if the repeat reading is lower, still consider referral if the level remains abnormal.
Do a PR to check for a nodule if thinking of just “seeing what the PSA does”
Palpable hard nodule, irrespective of PSA
WHEN TO STOP?
Elderly or infirm with <10 year anticipated survival
75 yo with PSA <3.0 (mortality from prostate cancer approaches zero)
A routine annual PR in the elderly/infirm to screen for locally advanced disease is reasonable.
Other PSA tips
- There is no need to order a routine U/S urinary tract if the only issue is an elevated screening PSA
- Don’t order a PSA in acute cystitis, acute retention, or acute symptoms of uncertain etiology as the result will usually be high, uninterpretable, and cause a lot of anxiety.
What about MRI Prostate?
This is a game-changer in prostate cancer diagnostics, with better detection of significant cancers. When combined with alterations in biopsy techniques, it may also reduce identification of insignificant cancers, and hence reduce over-diagnosis and overtreatment. mpMRI prostate is very difficult to perform and interpret correctly. It requires specialised MRI techniques, specific radiologist training, and urologist clinical input. Even in the best of hands, some significant cancers are still MRI invisible.
Given the potential for misinterpretation and misunderstanding of this emerging diagnostic aid, the general radiological and urological view is to refer any patient of concern to a Urologist before performing prostate MRI.