The best way to catch prostate cancer early could be entirely noninvasive, radiation-free, and low in cost. Multiparametric magnetic resonance imaging (MRI) with a targeted biopsy is more effective than the current standard — transrectal ultrasonography–guided biopsy — in detecting prostate cancer.
That’s according to a study in the New England Journal of Medicine. The authors caution that comparative evidence is limited, but the surprising results could change the way doctors approach suspected prostate cancer.
So what exactly is a multiparametric MRI scan? Well, MRI scans can be programmed to target different tissue behaviors; these pre-programmed pulse sequences are called “parameters.” For instance, technicians might scan for the movement of water or blood, or they might simply capture a broad-view image of the body. When a procedure involves more than one of these parameters, doctors call it “multiparametric.”
The researchers in the latest study conducted a randomized, noninferiority trial.
The multicenter study included 500 men who had a clinical suspicion of prostate cancer due to elevated prostate-specific antigen (PSA) level or an abnormal digital rectal examination. None had undergone a previous biopsy.
Half the men were given noninvasive MRI scans and half were given standard transrectal ultrasound–guided biopsies. Men in the first group whose scans did not suggest prostate cancer did not receive a biopsy. Those whose scans showed possible signs of the illness went on to receive a biopsy for confirmation.
Researchers found clinically significant cancer in 95 men (38 percent) in the MRI-targeted biopsy group compared to 64 (26 percent) of the men in the standard biopsy group. The authors concluded that “use of risk assessment with MRI before biopsy and MRI-targeted biopsy was superior to standard transrectal ultrasonography–guided biopsy in men at clinical risk for prostate cancer who had not undergone biopsy previously.”
In the last 10 years, standardization in conducting and reporting of multiparametric MRI has improved.
This has led to more accurate diagnosis of clinically significant cancer and reduction of overdiagnosis of low-grade cancers. The findings are significant because prostate cancer is the second leading cause of cancer death for men. Each year, there are about 165,000 new cases of and almost 30,000 deaths from prostate cancer. An even more startling statistic is that one in nine men will be diagnosed with the disease at some point in his lifetime.
A noninvasive method for detection could save a large number of lives by accurately assessing between clinically significant and non-significant prostate cancer. Survival rates for the disease are high, especially when patients receive treatment early in the cancer’s progression.
As the authors of the study note, “The ideal test for prostate cancer would be minimally invasive, have few side effects, identify a high proportion of men who would benefit from treatment, and minimize the identification of men with clinically insignificant cancer in order to prevent overtreatment.” While more testing is needed, multiparametric MRI seems to be that ideal test.
MRI scans show promising signs of replacing invasive diagnostic procedures.
The latest study is yet another that demonstrates how non-invasive detection of cancers is improving. A recent UT Southwestern study found that MRI scans could identify clear cell kidney carcinoma as accurately as biopsies. The impetus for that advancement was a similar improvement in conducting and reporting standards for MRI scans.
Taken together, these studies suggest that MRI scans are capable of capturing more information than we can currently decode. As techniques are refined and standardized, MRI scans may one day replace biopsies altogether.