Prostate Cancer

Research Details

Accuracy & equity in prostate cancer diagnosis in New Zealand
Gisborne, NZ

A new approach to prostate cancer diagnosis

Prostate cancer is the most commonly diagnosed cancer in New Zealand, and there are significant disparities in terms of diagnosis, treatment, and outcomes. Our project at Mātai aims to change this.

We are using advanced MRI techniques to improve how prostate cancer is diagnosed. This approach helps doctors decide whether a biopsy is needed and assists in performing targeted biopsies. Not only does this method help diagnose more serious prostate cancers, it also reduces the diagnosis of less serious cases and reduces the overall need for biopsies.

Thanks to support by the Hugh Green Foundation, the Prostate Cancer Foundation of New Zealand, Perpetual Guardian Cooper Legacies, and the Calvin Chua Philanthropic Trust, this diagnostic pathway is available as a free service to men in Tairāwhiti.

Men aged 50 and over should discuss prostate screening with their doctor. If you have a family history of prostate cancer, it is recommended that you begin this discussion from age 40.

The current scenario

At present, the standard practice in New Zealand is to perform a non-guided biopsy based on age and PSA levels. This method has several drawbacks:

It often misses the tumour (in about 25% of cases)
It can lead to an underestimation of the tumour’s size
It may unintentionally detect non-significant cancer

This current approach falls short in identifying younger men with significant but treatable disease. It also has a low screening rate in the most vulnerable populations and in those most likely to benefit.

OUR APPROACH

MRI & targeted biopsies

Our new diagnostic pathway uses MRI before a biopsy, which helps identify about 30% of men who can avoid invasive biopsies. We’ve worked with GE Healthcare to develop a 10-15 minute MRI scan protocol, much faster than the standard scan time of up to 45 minutes. This reduction in time lowers costs and enables more widespread use.

Furthermore, performing a targeted biopsy allows for a better understanding of the size, grade, and location of prostate cancers. This information is essential for personalised treatment planning.

Prostate cancer in New Zealand

Prostate cancer is a major health concern in New Zealand, with about 30,000 men living with prostate cancer that requires surveillance. Every year, around 650 New Zealand men die from prostate cancer. The 5-year survival rate is 98% with early diagnosis and drops to less than 20% if diagnosed late.

Inequalities in Prostate Cancer Outcomes

Men living in rural locations face higher mortality rates from prostate cancer and have lower screening rates, less intensive diagnostics, longer wait times, and later diagnoses. Our new diagnostic pathway aims to provide an equitable service which will improve prostate outcomes for all men in Tairāwhiti.

MRI Guided Prostate Ablation Treatment

COMING SOON

Papa Moana - Indigenous Care

COMING SOON

Current prostate diagnostic pathway results summary for Tairāwhiti

268 men with PSA greater than 4 have had a pre-biopsy MRI on the hospital 1.5T scanner.

25.0% of these men had an MRI that suggests biopsy can be avoided and that continued PSA monitoring with possible followup MRI can be performed.

220 men with PSA greater than 3.5 have had a pre-biopsy MRI on the Mātai 3T scanner.

43.6% of these men had an an MRI that suggests biopsy can be avoided and that continued PSA monitoring with possible followup MRI can be performed.

160 men have had a biopsy using the transperineal biopsy system at the hospital which allows targeted biopsies of any suspicious findings seen on the pre-biopsy MRI.

70.0% of men undergoing biopsy received a diagnosis of significant prostate cancer. These men need to have a discussion with their urologist regarding additional tests such as CT or PSMA PET. Most of these cancers will require treatment. Some can be closely watched.

14.4% percent of men undergoing biopsy received a diagnosis of low grade prostate cancer. Only a small number of these cancers require treatment. Most of these low grade cancers can be followed and are not thought to be life threatening.

The decision to treat versus followup as well as the best way to treat is made based on conversations with the urologist.

Of the 125 moderately suspicious findings on MRI that were targeted for biopsy, 55.2% of these turned out to be a significant cancer. 22.4% of these turned out to be a low grade cancer.

Of the 63 highly suspicious findings on MRI that were targeted for biopsy, 71.4% of these turned out to be a significant cancer. 17.5% of these turned out to be a low grade cancer.

Only 16 significant cancers were detected away from suspicious MRI findings. This happened in 12.7% of men undergoing biopsy.

We think these number are pretty good. If the MRI finds something abnormal, there is a good chance it is cancer.

81.4% of the targeted biopsy results were felt to be concordant – meaning that even if the biopsy result is something other than cancer – the MRI appearance is still felt, even in retrospect, to have warranted a biopsy. We would like this number to be close to 100% – but there will always be findings on the MRI that look like cancer but are actually not cancer.

A good target for this number is 75%.

Summary

Pre-biopsy MRI has allowed 33.2% of men being able to potentially defer biopsy. 84.4% of men undergoing biopsy were found to have prostate cancer. This suggests that the risk of a man with PSA over 3.5 having an unnecessary biopsy is low.

14.4% of men had low-grade prostate cancer. There is always the risk of over-treating these low-grade cancers so we would like to reduce the number of low-grade cancers that we detect.

With MRI and targeted biopsy after regular screening, we’re minimising the intervention cascade after PSA tests. You can use the numbers on this web-page as a starting point for discussing if having a PSA test is right for you.