Use of prostate systematic and targeted biopsy on the basis of multiparametric MRI in biopsy-naive patients (MRI-FIRST): a prospective, multicentre, paired diagnostic study

Summary Background Whether multiparametric MRIimproves the detection of clinically significant prostate cancer and avoids the need for systematic biopsyin biopsy-naive patients remains controversial. We aimed to investigate whether using this approach before biopsywould improve detection of clinically significant prostate cancer in biopsy-naive patients. Methods In this prospective, multicentre, paired diagnostic study, done at 16 centres in France, we enrolled patients aged 18–75 years with prostate-specific antigen concentrations of 20 ng/mL or less, and with stage T2c or lower prostate cancer. Eligible patients had been referred for prostate multiparametric MRIbefore a first set of prostate biopsies, with a planned interval of less than 3 months between MRI and biopsies. An operator masked to multiparametric MRIresults did a systematic biopsyby obtaining 12 systematiccores and up to two cores targeting hypoechoic lesions. In the same patient, another operator targeted up to two lesions seen on MRI with a Likert score of 3 or higher (three cores per lesion) using targeted biopsybased on multiparametric MRIfindings. Patients with negative multiparametric MRI(Likert score ≤2) had systematic biopsyonly. The primary outcome was the detection of clinically significant prostate cancer of International Society of Urological Pathology grade group 2 or higher (csPCa-A), analysed in all patients who received both systematicand targeted biopsiesand whose results from both were available for pathological central review, including patients who had protocol deviations. This study is registered with ClinicalTrials.gov, number NCT02485379, and is closed to new participants. Findings Between July 15, 2015, and Aug 11, 2016, we enrolled 275 patients. 24 (9%) were excluded from the analysis. 53 (21%) of 251 analysed patients had negative (Likert ≤2) multiparametric MRI. csPCa-A was detected in 94 (37%) of 251 patients. 13 (14%) of these 94 patients were diagnosed by systematic biopsyonly, 19 (20%) by targeted biopsyonly, and 62 (66%) by both techniques. Detection of csPCa-A by systematic biopsy(29·9%, 95% CI 24·3–36·0) and targeted biopsy(32·3%, 26·5–38·4) did not differ significantly (p=0·38). csPCa-A would have been missed in 5·2% (95% CI 2·8–8·7) of patients had systematic biopsynot been done, and in 7·6% (4·6–11·6) of patients had targeted biopsynot been done. Four grade 3 post- biopsyadverse events were reported (3 cases of prostatitis, and 1 case of urinary retentionwith haematuria). Interpretation There was no difference between systematic biopsyand targeted biopsyin the detection of ISUP grade group 2 or higher prostate cancer; however, this detection was improved by combining both techniques and both techniques showed substantial added value. Thus, obtaining a multiparametric MRIbefore biopsyin biopsy-naive patients can improve the detection of clinically significant prostate cancer but does not seem to avoid the need for systematic biopsy. Funding French National Cancer Institute.