MP56-06: Should we target all visible areas at mpMRI suspicious for clinically significant prostate cancer in addition to the index lesion? Results from a two-institution series

Armando Stabile, Jeffrey Karnes, Giovanni Motterle, Giorgio Gandaglia, Vito Cucchiara, Simone Scuderi, Francesco Barletta, Elio Mazzone, Daniele Robesti, Donato Cannoletta, Elio Zito, Pierre I Karakiewicz, Filippo Scalvi, Luigi Nocera, Emanuele Zaffuto, Paolo Dell'Oglio, Matteo Menean, Andrea Salonia, Francesco Montorsi, Francesco De Cobelli, Alberto Briganti

Introduction: It is well standardized to report detailed MRI characteristics of the so-called index lesion (IL) defined as the lesion with either the highest PI-RADS score or the largest size in men who received mpMRI of the prostate. However, little is known about the clinical significance of other MRI-visible areas suspicious for clinically significant prostate cancer (csPCa) in addition to the IL. We hypothesized that smaller, lower PI-RADS score lesions are of no clinical significance in these patients

Methods: We relied on 1760 men who underwent mp-MRI of the prostate with subsequent fusion targeted (TBx) and concomitant systematic biopsy at two tertiary referral centres between 2013 and 2019. For the study purposes, we identified 347 men with at least one suspicious lower PI-RADS lesion (secondary lesion) at mp-MRI in addition to the IL, defined as the lesion with the highest PI-RADS score. The study outcome was the added value of secondary lesions in the detection of csPCa (defined as Gleason score=7). For this aim, we included number and PI-RADS (<4 vs =4) of all secondary lesions and number of targeted cores to these secondary lesions in multivariable models predicting the presence of csPCa at TBx. All analyses were adjusted for age, PSA, prostate volume, PI-RADS (<4 vs =4) and number of targeted cores of the IL

Results: Overall, 43% of men had csPCa at TBx of all lesions. Of all 347 men, 91%, 8% and 1% had 1, 2 and 3 secondary lesions at prostate MRI in addition to the IL. Moreover, 37% and 22% of men had csPCa in the IL and in the secondary lesions, respectively. However, only 4% of men had csPCa found only in secondary lesions and not in the IL. The median volume of the IL and secondary lesions was 0.52 cc and 0.27 cc, respectively (p<0.001). At MVA, neither the number, nor the PI-RADS of secondary lesions, nor the number of cores targeting the secondary lesions was associated with the detection of csPCa (all p>0.3). Conversely, age (OR: 1.06), PSA (OR: 1.08), prostate volume (OR: 0.97), the number of IL targeted cores (OR: 1.04) and PI-RADS of the IL (OR: 2.57) were independently associated with csPCa detection at TBx (all p<0.009)

Conclusions: In this study including men with multiple lesions at mp-MRI, we demonstrated that the number, the PI-RADS and the number of targeted cores of secondary lesions did not improve the ability to detect csPCa at targeted biopsy. Therefore, for diagnostic purposes, biopsy of these lesions can be avoided and only the IL should be targeted and taken into account Source of

Funding: none