Accurate early diagnosis of prostate cancers
Posted on 22 November 2016
For more targeted prostate biopsies and to determine the stage of cancer more accurately, Mediclinic Cape Town together with urologist Dr Werner Botha have introduced the innovative BioJet MRI fusion-guided system.
By overlaying real-time ultrasound images with MRI-identified regions of interest, the new BioJet fusion-guided system at Mediclinic Cape Town reduces incidences of under-diagnosis or over-intervention. The biggest advantage of including MRI in the biopsy, compared with the standard 12-core method, is that urologists are diagnosing 40% more aggressive prostate cancers in very early stages, according to Dr Werner Botha, the urologist who is implementing the system.
What is the Biojet system?
The Biojet MRI-ultrasound fusion system is a high-resolution graphic software system developed by the physicist Peter Klews. A multi-parametric MRI of a patient’s prostate is performed and a radiologist specialising in prostate MRIs then maps out abnormal areas with the urologist. The following day, the patient is taken to theatre for the biopsy, where a real-time transrectal ultrasound is performed. The MRI and ultrasound images are fused by the program, minutely targeting problem areas and pinpointing where to biopsy. The urologist places the cursor on the targeted area, which provides a coordinate that indicates where to position the needle in the metal grid placed over the patient’s perineal area.
‘In 2000, transrectal ultrasounds for prostate biopsies were a major revelation, and the views of the prostate with ultrasounds have improved tremendously in the last 16 years since,’ reveals Dr Botha. ‘It is not adequate, however, to see tiny lesions of the prostate. MRIs of the prostate have also evolved since the eighties. The 3-Tesla magnet currently employed is perfect to give us clear imaging of the prostate.’
On Tuesday 8 November 2016, Dr Botha tested the Biojet system on two patients and reported that every biopsy tested positive for cancer, giving anecdotal proof of its accuracy.
‘In the past, using the standard 12-core method, 50-80% of significant cancers were missed, while at the same time insignificant or low-risk cancers – cancers that don’t require treatment – were overdiagnosed, leading to overtreatment,’ he says. ‘The prostate cancers we diagnose with the Biojet system are those that really need to be treated.’
Dr Botha points out that because tiny lesions that previously wouldn’t have been picked up can be identified using the MRI-ultrasound fusion system, it ensures that no cancer is missed. It also helps to determine the stage of prostate cancer and ensures that the healthy parts of a prostate are not biopsied. The Biojet system limits repeat biopsies, which limits scarring.
Who should be referred for this procedure?
Not all patients will be referred for the MRI fusion biopsy, partly because the MRI is an expensive investigation, although some funders will cover the cost.
Dr Botha lists ideal candidates:
- Men who have never undergone a biopsy but whose prostate-specific antigen (PSA) levels are rising.
- Men who have previously had a negative biopsy but whose PSA levels are still rising. ‘This is a very big group that we need to target because you can clearly see if there is a lesion that needs to be biopsied with the system,’ Dr Botha says.
- Men who have been diagnosed with prostate cancer and where active surveillance (watchful waiting) is recommended. Repeat MRIs and biopsies are utilised to monitor the cancer.
‘The Biojet allows us to keep a digital record of the locations in the prostate that have already been biopsied,’ Dr Botha notes.
How the Biojet stands apart from competitive systems
The Biojet system is relatively simple, requiring only the ultrasound machine, a laptop and a small metal grid placed on the patient that works with the coordinates on the screen. ‘This means that a suitably trained urologist can do the biopsy on their own, without a team of technicians in theatre,’ says Dr Botha.
The Biojet system also lowers the risk of infection during a biopsy. ‘While there are other systems that do this, they are more cumbersome and usually require a transrectal biopsy,’ he says. ‘The Biojet system allows the biopsy to be done transperineally – between the scrotum and the anus – which means there is a lower chance of infection.’
However, Dr Botha says that the MRI-ultrasound fusion system the urologist decides to use is a personal choice and dependant on the needs of the hospital, practice and patients. Currently, there are about six versions of these systems available internationally.
Dr Botha, a partner in Cape Urology Associates, introduced the system into Mediclinic Cape Town. He is working together with a team of eight urologists in the southern suburbs of Cape Town to ensure that targeted MRI-fusion transperineal biopsies have a wider patient reach.