Better Prostate Cancer Diagnosis With Targeted and Systematic Biopsies

The combined use of systematic and targeted magnetic resonance (MR)-ultrasound–guided fusion biopsy was effective in diagnosing clinically significant prostate cancer, according to results of a new study published in Cancer.

“Targeted biopsy using multiparametric magnetic resonance imaging (mpMRI) to guide tissue sampling can improve the detection of prostate cancer,” wrote study authors led by Leonard S. Marks, MD, of the David Geffen School of Medicine at the University of California, Los Angeles. Studies on this have been small, however, and questions remain regarding predictive value of the technique. “The key questions are whether a ‘normal’ mpMRI should preclude immediate biopsy and, if guided biopsy is performed, whether targeting alone can suffice.”

This prospective trial involved 1,042 men with a clinical suspicion of prostate cancer who underwent mpMRI before biopsy. All of the participants underwent systematic biopsy, and a subset then underwent targeted biopsy of “regions of interest.”

A total of 825 men had at least one suspicious region of interest; of those, 289 (35%) were found to have clinically significant prostate cancer (Gleason score ≥ 7). Combining targeted (specific cores from regions of interest) and systematic biopsy (12 cores in all men) yielded the 289 clinically significant cases, while targeted biopsy alone found only 229 cases and systematic biopsy alone found only 199 cases (P < .001).

Further, the combined biopsy approach found more high-risk prostate cancer cases, defined as those with a Gleason score of at least 8; it found 89 such cases, compared with 74 with targeted (P < .001) and 51 with systematic biopsy (P < .001).

In total, adding systematic biopsy to targeted biopsy resulted in 60 additional diagnoses of clinically significant prostate cancer, or 7% of the cohort with at least one region of interest. These cases would have been undiagnosed if only the regions of interest were targeted.

The grade of the regions of interest was directly correlated to the presence of clinically significant disease. About 80% of participants with a grade 5 region of interest were found to have prostate cancer with a Gleason score of 7 or above, compared with only 24% of those with a grade 3 region of interest. Prostate-specific antigen density was also significantly correlated with clinically significant prostate cancer.

The authors noted that about one in eight men with negative mpMRI findings were still found to harbor clinically significant disease. “The concept of using mpMRI to obviate prostate biopsy, if the imaging reveals no targets, should be regarded with caution,” they wrote. “MR-ultrasound fusion biopsy appears to be most accurate when the targeting of specific lesions is combined with systematic biopsy guided by software in the fusion device.”