All men with suspected prostate cancer should be offered a specialist MRI scan when they’re referred

All men with suspected prostate cancer should be offered a specialist MRI scan when they’re referred to the hospital in England, before a biopsy.

That’s the current recommendation from the National Institute for Health and Care Excellence (NICE) in its latest guidelines.

This special type of imaging, called multiparametric (mp)MRI, combines three different scans to help build a clearer picture of what’s going on in the prostate. The principle being that it can help to rule out or guide follow-up biopsies.

Using mpMRI should mean that fewer prostate cancers will be missed. And it should help to reduce the diagnosis of prostate cancers that would never have caused harm, so called overdiagnosis.

While the use of mpMRI is highly positive, not all hospitals are in a position to carry out this specialist methodology, with estimates suggesting that around only half of hospitals have their MRI optimised for this type of scan.

This raises questions over the optimal follow up for those men who do require further investigative treatment, ie. a prostate biopsy.

There have historically been two types of prostate biopsy. The most common method of prostate biopsy as of 2014 was transrectal ultrasound-guided prostate (TRUS) biopsy, whereby extended biopsy schemes take cores from the prostate gland through a thin needle in a systematic fashion from different regions of the prostate. The introduction of mpMRI has latterly introduced the concept of MRI-guided targeted biopsy, where the biopsy is concentrated on the findings of the MRI image.

In fact, a side-by-side comparison of TRUS versus MRI-guided targeted biopsy that was conducted as a prospective, investigator-blinded study[i] demonstrated that MRI-guided biopsy improved detection of significant prostate cancer by 17.7%, and decreased the diagnosis of insignificant or low-risk disease by 89.4%.

However, a new study recently published suggests that there is an alternative method that delivers greater detection of clinically significant prostate cancer. The Prospective Assessment of Image Registration in the Diagnosis of Prostate Cancer (PAIREDCAP) study is a comparison of targeted vs systematic prostate biopsy in men who are biopsy naïve – ie have had no previous prostate biopsy. The paired-cohort trial was conducted in an academic medical centre from January 2015 to April 2018. 300 men took part, of whom 248 had MRI-visible lesions. Clinically significant prostate cancer was diagnosed in 70%.

The study found that the targeted biopsy approach was marginally more sensitive than the systematic biopsy approach, but the 2 approaches combined detected 11% to 33% more cancers than either method alone, leading to the conclusion that “the addition of systematic sampling to targeting of magnetic resonance imaging–visible lesions resulted in a sensitivity for detection of clinically significant prostate cancer beyond that of either method alone”.