Transition to personalized software mpMR/US fusion prostate biopsy: a stratified retrospective analysis of 322 patients with development of a CHAID model

Petov V.S., Mursalov I.A., Rodionova V.K., Fokin I.V., Danilov S.P., Ganzha T.M., Kiriukhina M.A., Petrovsky V.F., Gerasimova P.M., Rzaev R.T., Enikeev M.E., Krupinov G.E., Amosov A.V.

1) Institute of Urology and Human Reproductive Health, Sechenov University, Moscow, Russia; 2) Institute of Clinical Medicine named after N.V. Sklifosovsky, Sechenov University, Moscow, Russia; 3) Institute of Clinical Medicine, Pirogov University, Moscow, Russia; 4) Department of Radiology, University Clinical Hospital No. 2, Sechenov University, Moscow, Russia

Introduction. MRI-targeted biopsy is the standard method for prostate cancer diagnosis; however, it is typically supplemented with perilesional or systematic biopsy to minimize the risk of false-negative results. Nevertheless, several studies have demonstrated the feasibility of performing MRI-targeted biopsy alone in carefully selected patients.
Objective. To identify factors allowing MRI-targeted biopsy to be performed alone without compromising the detection of clinically significant prostate cancer (csPCa).
Materials and Methods. A retrospective analysis was conducted in patients who underwent transperineal software mpMR/US fusion and saturation biopsy. Inclusion criteria were PSA ≥2 ng/ml and/or the presence of a suspicious lesion on digital rectal examination (DRE) and/or transrectal ultrasound (TRUS), as well as a PI-RADS v2.1 score ≥3. Factors included in the stratified analysis were: type of biopsy, PI-RADS score, suspicious lesion on TRUS or DRE, PSA level, PSA density, and lesion size. To formulate clinical rules, a CHAID decision tree algorithm was developed with the following variables: detection of csPCa on software mpMR/US fusion biopsy, PI-RADS score, PSA density, lesion size, age, and type of biopsy. CsPCa was defined as ISUP grade ≥2.
Results. A total of 322 patients were included (median age 63 years, PSA 6.7 ng/ml, prostate volume 48 cm³). Primary biopsy was performed in 241 patients (74.8%) and repeat biopsy in 81 patients (25.2%). The detection rate of csPCa did not differ significantly between software mpMR/US fusion and combined biopsy (23.6% vs 30.4%; p=0.051). The additional diagnostic value of saturation biopsy for csPCa was 6.8% (range 0–28.6%). Stratified analysis showed no added value of saturation biopsy in primary biopsy patients with PI-RADS 5 lesions, PI-RADS 3–4 lesions with adverse factors, and in repeat biopsy patients with PI-RADS 5 lesions and adverse factors. The developed CHAID model demonstrated an accuracy of 80.2%, sensitivity of 100%, and specificity of 60.7%. According to the model, saturation biopsy was considered unnecessary in patients with PI-RADS 5 lesions with adverse factors, as well as in patients with PI-RADS ≤4 lesions combined with PSA density ≤0.20 ng/ml/cm³ and lesion size ≤10–12 mm. Application of the CHAID algorithm could reduce the number of saturation biopsies by 60.5% with a missed csPCa risk of ≤3.3%.
Conclusion. The presented results indicate that combined biopsy can be safely replaced by only MRI-targeted approaches in carefully selected patients without a substantial risk of missing csPCa, thereby creating a basis for the implementation of personalized prostate biopsy strategies.

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About the Authors

Corresponding author: V.S. Petov – Urologist, PhD (Cand. Med. Sci.), Assistant Professor, Institute of Urology and Human Reproductive Health, Sechenov University, Moscow, Russia; e-mail: pettow@mail.ru

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