Ultrasound scans can detect prostate cancer with close to same accuracy as MRI, finds UK-based study

MRI scan is considered to be gold standards for diagnosis of structural abnormalities without using a non-invasive tool. But often when doctor’s asks to go for an MRI scan it rings a bell in everyone’s mind of cancer is suspected. But since ultra sound is used for primary imaging to locate the source of the problem and MRI gives a more detailed analysis, the later often over rules the former.

New research now underscores the importance of good old ultrasound that is available in detecting cancer. Researchers at Imperial College, University College London and Imperial College Healthcare NHS Trust have used a new kind of ultrasound technique to detect cases of prostate cancer with good accuracy.

The trial involved 370 men. The scan technique missed only 4.3 per cent more clinically important prostate cancer cases compared to MRI scans

This study makes detecting prostate cancer that needs to be treated rather than monitored easier, less expensive and not time-consuming. The study further establishes why low- and middle-income countries should take ultra sound as the first test in community healthcare settings.

Professor Hashim Ahmed, lead author of the study finds that the findings of the study help in maximizing detection of prostate cancer, the most commonly diagnosed cancer in the UK. One in six men are diagnosed with prostate cancer in the UK and the number is expected to grow, he said.

Dr Ahmed further said that the study is first of its kind to show that a special type of ultrasound scan can be used as a potential test to detect clinically significant cases of prostate cancer and can be used by patients who are unable to get MRI scans due to hip replacements or are claustrophobic.

Around 52,300 cases of prostate cancer are diagnosed in the UK every year. It is developed when cells grow in an uncontrolled way. Symptoms once disease has fully developed include blood in urine. Black men over 50 and with a family history of the disease are most affected by prostate cancer.  A special type of MRI scan is conducted called multi-parametric MRI for doctors to find out if the cancer is inside the prostate and how quickly it will grow.

The new study used multi-parametric ultrasound technique where sound waves are used. A transducer is used to make images of the prostate. The transducer is placed in the rectum and it sends out sound waves that bounce off organs and other structures making images.

The doctor used special types of ultrasound imaging to understand how stiff the tissue is and how much blood supply the tissue through elastography, contrast-enhancement etc. The tissues with greater blood supply appear more clearly.

The study took place at seven hospitals in the UK between March2016 and November 2019.  370 subjects at risk of prostate cancer first went through initial tests like  blood test, prostate specific antigen test and abnormal digital rectal examination. The subjects were then given both MRI and ultrasound scans. This was followed by biopsies for 257 patients with positive MRI and Ultrasound reports. Cancer was detected in 133 men, 83 had clinically insignificant cancer.

The special ultrasound technique accurately detected cancer in 66 cases while MRI in 77 cases. Even with 4.3 per cent lesser detection rate than MRI, researchers said this method will lead to 11.1 per cent increase in diagnosis in patients. Hence, they underscore the use of the technique as an alternative to mpMRI as a primary test for patients at risk. But using both can increase accuracy in detection of clinically important prostate cancer cases compared to taking any one of the tests.