MRI could be a valuable asset in certain prostate cancer patient populations

MRI could be of value in the diagnosis of prostate cancer in patients with histories of negative biopsies and elevated levels of prostate-specific antigen (PSA), according to a study published in the May issue of Academic Radiology.

As the incidence of prostate cancer rises amongst men, many are concerned by the way in which the disease is currently diagnosed. Random biopsies are often performed on the prostate with transrectal ultrasound (TRUS). “However, because of the high false-negative rates and very low false-positive rates of initial TRUS-guided biopsy (TRUS-GB), patients may still have cancer despite a negative biopsy,” wrote lead author Zai-Xian Zhang, MD, PhD, of Shanghai Jiao Tong University in China, and colleagues. “Patients with previous negative biopsy results and persistently increasing PSA levels require repeat biopsies, which negatively affect their quality of life.”

MRI offers a potential alternative to TRUS because of its higher sensitivity. Zhang and colleagues sought to synthesize the current bulk of information available in order to assess the diagnostic efficacy of MRI in discovering prostate cancer in patients with previous negative biopsies and persistently elevated PSA levels.

The researchers searched Pubmed, Scopus, and Cochrane Library to identify pertinent studies published between 2001 and 2013. Using a random effect model, they then acquired polled estimation and subgroup analysis data. Overall test performance was then summarized through the utilization of summary receiver operating characteristic curves.

After examining 14 studies that involved 698 patients, Zhang and colleagues discovered the mean prostate cancer detection rate was 37.5 percent. Twelve studies exhibited a pooled sensitivity of 88 percent and a specificity of 69 percent.

Subgroup analysis revealed that MRI spectroscopy offered higher pooled sensitivity and specificity than T2-weighted images, at 91 and 69 percent respectively. Combining MRI spectroscopy (MRSI) with MRI yielded the highest pooled specificity at 73 percent.  The subgroup analysis revealed that MRSI combined with MRI demonstrated higher pooled sensitivity (58 percent) and specificity (93 percent) when compared with T2-weighted images. Diffusion-weighted MRI showed the highest pooled specificity at 95 percent, yet it had the lowest pooled sensitivity at 38 percent.

“On the basis of the results of our study, we confirm that MRSI or MRI/MRSI-directed TRUS-GB has a potential role in the diagnosis of prostate cancer and is more efficient than conventional TRUS-GB for patients who had previous negative biopsy,” wrote the authors. “In addition, there is evidence that the use of MRI/MRSI to plan targeted biopsies may lead to the detection of cancers that would have been missed on systematic biopsies. Results of a recent systematic review also showed the similar situation. We speculate that further improvement of the multiparametric MRI will increase its role in the future,” they surmised.