A variation of ultrasound imaging, called shear wave elastography (SWE), may help detect signs of prostate cancer with higher accuracy and reliability than current methods, according to new research.
The study, “Performance characteristics of transrectal shear wave elastography (SWE) imaging in the evaluation of clinically localised prostate cancer: a prospective study,” was published in the Journal of Urology.
Prostate cancer diagnosis now relies on a blood test that measures the amount of a marker, called prostate specific antigen (PSA), along with physical examination of the prostate, known as a digital rectal examination.
These methods, however, are far from perfect: PSA test results may be unreliable, and the physical examination is unable to distinguish a benign from a malignant tumor. As a result, patients often undergo magnetic resonance imaging (MRI) scans — which is expensive and not always readily available — and ultimately a biopsy of the prostate tissue — an invasive and expensive surgical procedure.
“Prostate cancer is one of the most difficult to pinpoint. We are still in a position where our diagnosis of prostate cancer is extremely inefficient, leading to unnecessary treatments for many patients,” Ghulam Nabi, professor of Surgical Uro-oncology at the University of Dundee in Scotland and the study’s lead author, said in a press release.
“The new method we have developed shows we can achieve much greater levels of diagnosis, including identifying the difference between cancerous and benign tissue without the need for invasive surgery,” he said.
Their method relies on shear wave elastography (SWE), a noninvasive imaging strategy that uses ultrasound waves targeted at the prostate tissue to assess tissue stiffness. Cancer tissues are generally stiffer than healthy tissues, meaning the shear waves will slow down as they pass a tumor.
By measuring the speed of the waves, researchers are able to create images of the area being scanned more accurately than those obtained using an MRI scan.
Although researchers had previously shown the technique’s potential for improving prostate cancer diagnosis, it lacked testing on a larger scale.
To address this, they recruited 212 men with a localized prostate tumor, who were undergoing surgery for prostate removal. Before surgery, patients underwent transrectal ultrasound SWE scanning of the prostate gland.
Results showed that SWE detected 89% of the prostate cancers and was able to distinguish more aggressive tumors from low-risk ones.
“We have been able to show a stark difference in results between existing techniques such as MRI and SWE,” Nabi said. “We have had cases where the SWE technique has picked up cancers which MRI did not reveal.
“It is like someone has turned the lights on in a darkened room. We can now see with much greater accuracy what tissue is cancerous, where it is and what level of treatment it needs.”
“This research has shown the potential of a novel form of ultrasound called shear wave elastography in detecting clinically significant prostate cancer,” said Simon Grieveson, head of research funding at Prostate Cancer UK, which helped to fund the project. “If proven to be effective, this could lead to a more accurate and cost effective option than current diagnostic tests.”
“This promising new technique now needs to be tested in a much larger number of men to confirm just how well it can detect the aggressive cancers, whilst also ruling out those who do not have prostate cancer. We look forward to further results in this area,” he said.