Advances In Accuracy And Equity In Prostate Cancer
A PARADIGM SHIFT
THE CURRENT STANDARD OF CARE IN NEW ZEALAND IS TO PERFORM A BLIND, NON-GUIDED BIOPSY BASED ON AGE AND PSA LEVELS.
25% of cases: Biopsy misses the tumour
Fortuitous reaching of non-significant cancer
Underestimation of tumour's size
Images by Koelis.com
The diagnostic Pathway for prostate cancer in New Zealand is inefficient, expensive, and inequitable. In the public health system, the main approach to prostate cancer diagnosis involves a clinical assessment by a urologist, followed by a blind untargeted biopsy. We do not screen for prostate cancer wisely or equitably. When we do screeen we are good at identifying older men with untreatable metastatic disease and younger men with treatable but insignificant disease (because we do not know the size or location of the tumours). We fall short in identifying younger men with significant, but treatable disease.
Other major shortcomings of this system include (1) Low rates of screening in both the most vulnerable populations as well as in the populations most likely to benefit. (2) Limitations of non-targeted biopsy to adequately sample the prostate, characterise tumours, and facilitate treatment planning.
Mātai proposes a new diagnostic pathway using pre-biopsy MRI and targeted biopsies. Internationally, MRI is often used as the first step in diagnosis. Partnering with GE Healthcare, Mātai scientists have implemented a 10-15 minute MRI scan protocol. The current standard scan time is 45minutes. Faster scan time results in lower cost and enables more prolific use. In addition, MRI performed prior to biopsy identifies approximately 30% of men who can avoid invasive biopsies.
By using one of the worlds most advanced MRI protocols and guided MRI/Ultrasound fusion biopsy, we aim to significantly reduce the inequity in access to prostate cancer diagnosis, treatment, and management.
Performing a targeted biopsy allows for correlation between the biopsy sample and imaging so that the size, grade, and location of prostate cancers can be correlated. Without this correlation, one does not know if the edge of a large tumour or the center of a small tumour was sampled. it is also possible that the biopsies have missed the tumour. Radiology / pathology correlation allows for increased risk stratification and personalised treatment planning.
Prostate cancer is the most commonly diagnosed cancer in New Zealand, accounting for 1 in 6 of all cancers diagnosed. Approximately 30,000 New Zealand men are living with prostate cancer that requires surveillance, and every year around 650 New Zealand men die from prostate cancer.
Early and accurate diagnosis of prostate cancer is essential, especially in young men. The 5 year survival rate is 98% with early diagnosis and <20% if diagnosed late.
Māori men, especially living in rural locations, are twice as likely to die from prostate cancer, have lower screening rates, less intensive diagnostics, longer wait times, later diagnosis, and differences in treatment. Because Māori make up approximately 40% of the male population in Tairāwhiti, the known inequities are magnified.
This research project by Mātai will provide an evidence based rationale to encourage the New Zealand Health system, in particular, rural health providers, to change the process by which prostate cancer is diagnosed by making MRI the first step and using guided biopsy. This would provide faster and local access to more accurate prostate biopsy and treatment across a broader group of the population, including at risk younger men, and allow urology staff to see more patients with copnditions other than suspected prostate cancer. However, an investment in guided biopsy machines by healthcare providers would be required.