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Objective: To compare different stereotactic body techniques—intensity-modulated radiotherapy with photons and protons, applied to radiotherapy of prostatic cancer—with simultaneous integrated boost (SIB) on the dominant intraprostatic lesion (DIL).Methods: Ten patients were selected for this planning study. Dosimetric results were compared between volumetric modulated arc therapy, intensity-modulated radiation therapy (IMRT), and intensity-modulated proton therapy both with two (IMPT 2F) and five fields (IMPT 5F) planning while applying the prescription schemes of 7.25 Gy/fraction to the prostate gland and 7.5 Gy/fraction to the DIL in 5 fractions.Results: Comparison of the coverages of the planning target volumes showed that small differences exist. The IMPT-2F-5F techniques allowed higher doses in the targets; conformal indexes resulted similar; homogeneity was better in the photon techniques (2%–5%). Regarding the organs at risk, all the techniques were able to maintain the dose well below the prescribed constraints: in the rectum, the IMPT-2F-5F and IMRT were more efficient in lowering the intermediate doses; in the bladder, the median dose was significantly better in the case of IMPT (2F–5F). In the urethra, the best sparing was achieved only by IMPT-5F.Conclusions: Stereotactic radiotherapy with SIB for localized prostate cancer is feasible with all the investigated techniques. Concerning IMPT, the two-beam technique does not seem to have a greater advantage compared to the standard techniques; the 5-beam technique seems more promising also accounting for the range uncertainty.

Background: To test clinically significant prostate cancer (csPCa) rates during follow-up in biopsy naïve patients that underwent two different diagnostic pathways: (1) SB GROUP (n= 354): systematic random biopsies (SB) vs. (2) TB GROUP (n= 264): multiparametric magnetic resonance imaging (mpMRI) and only targeted biopsies (TB) of PI-RADS ≥ 3 lesions. Patients with PI-RADS ≤ 2 score avoided prostate biopsies. Methods: Retrospective single centre study of 618 biopsy naive patients (2015–2018). Two different definitions of csPCa were used: (1) csPCa ISUP GG ≥ 2 (ISUP grade group [GG] ≥ 2) and (2) csPCa ISUP GG ≥ 3. Kaplan–Meier plots and univariable Cox regression models tested rates over time of csPCa ISUP GG ≥ 2 and caPCa ISUP GG ≥ 3 in SB GROUP vs. TB GROUP. Results: At initial biopsy, TB achieved higher rates of csPCa ISUP GG ≥ 2 (35.3 vs. 18.9%; p< 0.001) and csPCa ISUP GG ≥ 3 (12.6 vs. 6.2%; p= 0.04), relative to SB. After a median time follow-up of 36 months, the rates of csPCa ISUP GG ≥ 2 (6.1 vs. 4.4%; p= 0.6) and csPCa ISUP GG ≥ 3 (3.3 vs. 1.1%; p= 0.2) were similar in SB GROUP vs. TB GROUP. Moreover, in TB GROUP patients that avoided prostate biopsies because of negative baseline mpMRI (n= 145), only 4.1% exhibited csPCa ISUP GG ≥ 2 during follow-up. Moreover, none of these patients (PI-RADS ≤ 2) had csPCa ISUP GG ≥ 3. Conclusions: In biopsy naïve setting, a diagnostic pathway including pre-biopsy mpMRI and TB of only PCa suspicious lesions is not associated with higher rates of csPCa during follow-up, relative to a diagnostic pathway of SB. Moreover, patients with negative baseline mpMRI could safely avoid prostate biopsies and could be followed with repeated PSA testing, since only a small proportion of them would harbor csPCa.

Background: To understand the value of multiparametric magnetic resonance imaging (mpMRI) and targeted biopsies at recruitment on active surveillance (AS) outcomes. Materials and methods: This retrospective single-center study enrolled two cohorts of 206 and 310 patients in AS. The latter group was submitted to mpMRI and targeted biopsies at recruitment. Kaplan–meier curves quantified progression-free survival (PFS) and Bioptic-PFS (B-PFS: no upgrading or >3 positive cores) in the two cohorts. Cox-regression analyses tested independent predictors of PFS and B-PFS. In patients submitted to radical prostatectomy (RP) after AS, significant cancer (csPCa) was defined as: GS ≥ 4 + 3 and/or pT ≥ 3a and/or pN+ . Logistic-regression analyses predicted csPCa at RP. Results and limitations: Median time follow-up and median time of persistence in AS were 46 (24–70) and 36 (23–58) months, respectively. Patients submitted to mpMRI at AS begin, showed greater PFS at 1- (98% vs. 91%), 3- (80% vs. 57%), and 5-years (70% vs. 35%) follow-up, respectively (all p< 0.01). At Cox-regression analysis only confirmatory mpMRI± targeted biopsy (HR: 0.3; 95% CI 0.2–0.5; p< 0.01) at AS begin was an independent predictor of PFS. Globally, 50 (16%) vs. 128 (62%) and 26 (8.5%) vs. 64 (31%) [all p< 0.01] men in the two groups experienced any-cause and bioptic AS discontinuation, respectively. Patients submitted to confirmatory mpMRI experienced greater 1-(98% vs. 93%), 3-(90% vs. 75%), and 5-years (83% vs. 56%) B-PFS, respectively (all p< 0.01). At Cox-regression analysis, mpMRI±-targeted biopsy at AS begin was associated with B-PFS (HR: 0.3; 95% CI 0.2–0.6; p< 0.01). No differences were recorded in csPCa rates between the two groups (22% vs. 28%; p= 0.47). Limitations of the study are the single-center retrospective nature and the absence of long-term follow-up. Conclusions: Confirmatory mpMRI±-targeted biopsies are associated with higher PFS and B-PFS during AS. However, a non-negligible percentage of patients experience csPCa after switching to active treatment.

To understand the multiparametric magnetic resonance imaging (mpMRI) interreader agreement between radiologists of peripheral and academic centers and the possibility to avoid prostate biopsies according to magnetic resonance imaging second opinion.

: To investigate the use of apparent diffusion coefficient (ADC) values and other MRI features for the prediction of positive surgical margins (PSMs) in patients undergoing radical prostatectomy.

Background: The METastasis Reporting and Data System for Prostate Cancer (MET-RADS-P) guidelines are designed to enable reproducible assessment in detecting and quantifying metastatic disease response using whole-body magnetic resonance imaging (WB-MRI) in patients with advanced prostate cancer (APC). Methods: Fifty consecutive paired WB-MRI examinations, performed from December 2016 to February 2018 on 31 patients, were retrospectively examined to compare reports by a Senior Radiologist (9 years of experience in WB-MRI) and Resident Radiologist (after a 6-months training) using MET-RADS-P guidelines, for detection and for primary/dominant and secondary response assessment categories (RAC) scores assigned to metastatic disease in 14 body regions. Inter-observer agreement regarding RAC score was evaluated for each region by using weighted-Cohen’s Kappa statistics (K). Results: The number of metastatic regions reported by the Senior Radiologist (249) and Resident Radiologist (251) was comparable. For the primary/dominant RAC pattern, the agreement between readers was excellent for the metastatic findings in cervical, dorsal, and lumbosacral spine, pelvis, limbs, lungs and other sites (K:0.81–1.0), substantial for thorax, retroperitoneal nodes, other nodes and liver (K:0.61–0.80), moderate for pelvic nodes (K:0.56), fair for primary soft tissue and not assessable for skull due to the absence of findings. For the secondary RAC pattern, agreement between readers was excellent for the metastatic findings in cervical spine (K:0.93) and retroperitoneal nodes (K:0.89), substantial for those in dorsal spine, pelvis, thorax, limbs and pelvic nodes (K:0.61–0.80), and moderate for lumbosacral spine (K:0.44). Conclusions: We found inter-observer agreement between two readers of different expertise levels to be excellent in bone, but mixed in other body regions. Considering the importance of bone metastases in patients with APC, our results favor the use of MET-RADS-P in response to the growing clinical need for monitoring of metastasis in these patients.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.