Results from a clinical trial showed that ultrasound scans are effective in prostate cancer diagnosis, which would be a cheaper option than MRI for low- and middle income countries. The study is published in Lancet Oncology.
“MRI scans are one of the tests we use to diagnose prostate cancer,” said Professor Hashim Ahmed, lead author of the study and Chair of Urology at Imperial College London. “Although effective, these scans are expensive, take up to 40 minutes to perform and are not easily available to all. Also, there are some patients who are unable to have MRI scans such as those with hip replacements or claustrophobia fears. As cancer waiting lists build as a result of the COVID pandemic, there is a real need to find more efficient and cheaper tests to diagnose prostate cancer.
“Our study is the first to show that a special type of ultrasound scan can be used as a potential test to detect clinically significant cases of prostate cancer. They can detect most cases of prostate cancer with good accuracy, although MRI scans are slightly better.
“We believe that this test can be used in low and middle income settings where access to expensive MRI equipment is difficult and cases of prostate cancer are growing.”
Prostate cancer develops slowly and symptoms such as the blood in the urine do not appear until the disease has developed. It usually affects men over 50 and often men with a family history of the disease. Black men are disproportionately impacted by the disease and prostate cancer deaths now exceed those from breast cancer.
One of the principal means of prostate cancer diagnosis is a multi-parametric MRI (mpMRI) scan. However, the 40-minute scan costs £350–450 (R7000-9000).
This new study tested multiparametric ultrasound (mpUSS) to image the prostate. Elastography examines tissue hardness, doppler and contrast-enhancement with microbubbles measures blood flow. As cancers are denser and have greater blood supply, they show up more clearly.
While mpUSS is more widely available than mpMRI, no large-scale studies have been done thus far to validate its effectiveness as a test to detect prostate cancer cases.
For the trial the team recruited 370 men at risk of prostate cancer. They were identified following initial tests such as a prostate-specific antigen (PSA) test and/or an abnormal digital rectal examination.
The men underwent both mpUSS and mpMRI scans at separate visits. This was then followed by biopsies for 257 patients who had a positive mpUSS or mpMRI test result. Cancer was detected in 133 men, with 83 men diagnosed with clinically significant cancer.
Individually, mpUSS detected 66 cases of clinically significant cancer compared to mpMRI which detected 77 cases.
Although mpUSS detected 4.3% fewer clinically-important prostate cancers compared to mpMRI, this method would lead to 11.1% more patients being biopsied as a result of false positives from the mpUSS.
The researchers believe that mpUSS could be an alternative to mpMRI as a first test for patients at risk of prostate cancer, particularly where mpMRI cannot be carried out. As both imaging tests missed clinically-important cancers detected by the other, using both would increase the detection of clinically-important prostate cancers overall.
Source: Imperial College London
