MRI-Guided Targeted and Systematic Prostate Biopsies as Prognostic Indicators for Prostate Cancer Treatment Decisions

SIMPLE SUMMARY: The term “clinically relevant prostate carcinoma” (csPCa) is used to differentiate the types of prostate carcinoma (PCa) that can lead to the death of the affected patient from those tumor types that usually do not. Targeted biopsies (TBx) of visible lesions in an MRI of the prostate has increased the detection of csPCa. The aim of this prospective study is to assess the extent to which the collection of TBx alone was sufficient for the correct diagnosis of therapy-relevant PCa and how often the results of systematic biopsies (SBx) were crucial for the treatment decisions. Depending on the definition of a csPCa, 80–90% of therapy-relevant tumors were detected with TBx alone. ABSTRACT: The standard procedure for the diagnosis of prostate carcinoma involves the collection of 10–12 systematic biopsies (SBx) from both lobes. MRI-guided targeted biopsies (TBx) from suspicious foci increase the detection rates of clinically significant (cs) PCa. We investigated the extent to which the results of the TBx predicted the tumor board treatment decisions. SBx and TBx were acquired from 150 patients. Risk stratifications and recommendations for interventional therapy (prostatectomy and radiotherapy) or active surveillance were established by interdisciplinary tumor boards. We analyzed how often TBx alone were enough to correctly classify the tumors as well as to indicate interventional therapy and how often the findings of SBx were crucial for therapy decisions. A total of 28/39 (72%) favorable risk tumors were detected in TBx, of which 11/26 (42%) very-low-risk tumors were not detected and 8/13 (62%) low-risk tumors were undergraded. A total of 36/44 (82%) intermediate-risk PCa were present in TBx, of which 4 (9%) were underdiagnosed as a favorable risk tumor. A total of 12/13 (92%) high-risk carcinomas were detected and correctly grouped in TBx. The majority of csPCa were identified by the sampling of TBx alone. The tumor size was underestimated in a proportion of ISUP grade 1 tumors. Systematic biopsy sampling is therefore indicated for the next AS follow-up in these cases.