Weakly Supervised MRI Slice-Level Deep Learning Classification of Prostate Cancer Approximates Full Voxel- and Slice-Level Annotation: Effect of Increasing Training Set Size.

BACKGROUND: Weakly supervised learning promises reduced annotation effort while maintaining performance. PURPOSE: To compare weakly supervised training with full slice-wise annotated training of a deep convolutional classification network (CNN) for prostate cancer (PC). STUDY TYPE: Retrospective. SUBJECTS: One thousand four hundred eighty-nine consecutive institutional prostate MRI examinations from men with suspicion for PC (65 ± 8 years) between January 2015 and November 2020 were split into training (N = 794, enriched with 204 PROSTATEx examinations) and test set (N = 695). FIELD STRENGTH/SEQUENCE: 1.5 and 3T, T2-weighted turbo-spin-echo and diffusion-weighted echo-planar imaging. ASSESSMENT: Histopathological ground truth was provided by targeted and extended systematic biopsy. Reference training was performed using slice-level annotation (SLA) and compared to iterative training utilizing patient-level annotations (PLAs) with supervised feedback of CNN estimates into the next training iteration at three incremental training set sizes (N = 200, 500, 998). Model performance was assessed by comparing specificity at fixed sensitivity of 0.97 [254/262] emulating PI-RADS ≥ 3, and 0.88-0.90 [231-236/262] emulating PI-RADS ≥ 4 decisions. STATISTICAL TESTS: Receiver operating characteristic (ROC) and area under the curve (AUC) was compared using DeLong and Obuchowski test. Sensitivity and specificity were compared using McNemar test. Statistical significance threshold was P = 0.05. RESULTS: Test set (N = 695) ROC-AUC performance of SLA (trained with 200/500/998 exams) was 0.75/0.80/0.83, respectively. PLA achieved lower ROC-AUC of 0.64/0.72/0.78. Both increased performance significantly with increasing training set size. ROC-AUC for SLA at 500 exams was comparable to PLA at 998 exams (P = 0.28). ROC-AUC was significantly different between SLA and PLA at same training set sizes, however the ROC-AUC difference decreased significantly from 200 to 998 training exams. Emulating PI-RADS ≥ 3 decisions, difference between PLA specificity of 0.12 [51/433] and SLA specificity of 0.13 [55/433] became undetectable (P = 1.0) at 998 exams. Emulating PI-RADS ≥ 4 decisions, at 998 exams, SLA specificity of 0.51 [221/433] remained higher than PLA specificity at 0.39 [170/433]. However, PLA specificity at 998 exams became comparable to SLA specificity of 0.37 [159/433] at 200 exams (P = 0.70). DATA CONCLUSION: Weakly supervised training of a classification CNN using patient-level-only annotation had lower performance compared to training with slice-wise annotations, but improved significantly faster with additional training data. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

Prostate cancer risk assessment and avoidance of prostate biopsies using fully automatic deep learning in prostate MRI: comparison to PI-RADS and integration with clinical data in nomograms.

OBJECTIVES: Risk calculators (RCs) improve patient selection for prostate biopsy with clinical/demographic information, recently with prostate MRI using the prostate imaging reporting and data system (PI-RADS). Fully-automated deep learning (DL) analyzes MRI data independently, and has been shown to be on par with clinical radiologists, but has yet to be incorporated into RCs. The goal of this study is to re-assess the diagnostic quality of RCs, the impact of replacing PI-RADS with DL predictions, and potential performance gains by adding DL besides PI-RADS. MATERIAL AND METHODS: One thousand six hundred twenty-seven consecutive examinations from 2014 to 2021 were included in this retrospective single-center study, including 517 exams withheld for RC testing. Board-certified radiologists assessed PI-RADS during clinical routine, then systematic and MRI/Ultrasound-fusion biopsies provided histopathological ground truth for significant prostate cancer (sPC). nnUNet-based DL ensembles were trained on biparametric MRI predicting the presence of sPC lesions (UNet-probability) and a PI-RADS-analogous five-point scale (UNet-Likert). Previously published RCs were validated as is; with PI-RADS substituted by UNet-Likert (UNet-Likert-substituted RC); and with both UNet-probability and PI-RADS (UNet-probability-extended RC). Together with a newly fitted RC using clinical data, PI-RADS and UNet-probability, existing RCs were compared by receiver-operating characteristics, calibration, and decision-curve analysis. RESULTS: Diagnostic performance remained stable for UNet-Likert-substituted RCs. DL contained complementary diagnostic information to PI-RADS. The newly-fitted RC spared 49% [252/517] of biopsies while maintaining the negative predictive value (94%), compared to PI-RADS ≥ 4 cut-off which spared 37% [190/517] (p < 0.001). CONCLUSIONS: Incorporating DL as an independent diagnostic marker for RCs can improve patient stratification before biopsy, as there is complementary information in DL features and clinical PI-RADS assessment. CLINICAL RELEVANCE STATEMENT: For patients with positive prostate screening results, a comprehensive diagnostic workup, including prostate MRI, DL analysis, and individual classification using nomograms can identify patients with minimal prostate cancer risk, as they benefit less from the more invasive biopsy procedure. KEY POINTS: The current MRI-based nomograms result in many negative prostate biopsies. The addition of DL to nomograms with clinical data and PI-RADS improves patient stratification before biopsy. Fully automatic DL can be substituted for PI-RADS without sacrificing the quality of nomogram predictions. Prostate nomograms show cancer detection ability comparable to previous validation studies while being suitable for the addition of DL analysis.

Microenvironment-Derived FGF-2 Stimulates Renal Cell Carcinoma Cell Proliferation through Modulation of p27Kip1: Implications for Spatial Niche Formation and Functional Intratumoral Heterogeneity.

BACKGROUND/OBJECTIVE: Clear cell renal cell carcinoma (ccRCC) is characterized by a high degree of functional intratumoral heterogeneity (ITH). This is highlighted by the finding that tumor cell proliferation and intracellular signaling occur preferentially in the tumor periphery. The driving forces for such a spatial organization are largely unknown. Herein, we investigate the role of the tumor microenvironment in the control of tumor cell proliferation and functional ITH. METHODS: Conditioned media (CM) derived from nonmalignant peritumoral kidney tissue were used to stimulate RCC cells in vitro. A neutralization assay was used to characterize the role of FGF-2 in the CM. The molecular mechanisms underlying the action of CM on RCC cells were investigated using immunoblotting, flow cytometry and immunofluorescence microscopy. Lastly, a series of ccRCCs were stained for Ki-67 and p27Kip1, and expression was analyzed in both tumor periphery and center. RESULTS: We show that CM derived from nonmalignant kidney cells adjacent to an RCC can downregulate the expression of the CDK inhibitor p27Kip1 through enhanced protein degradation in an FGF-2-dependent fashion. FGF-2 functions mainly through the PI3K/AKT pathway downstream of its receptors, and RCC cells with constitutively high AKT activity show not only an enhanced degradation of p27Kip1 through the Emi1-Skp2 axis, but also a subcellular mislocalization of p27Kip1 to the cytoplasmic compartment. Such a mislocalization was also detected in the tumor periphery in vivo suggesting that p27Kip1 plays an important role in shaping this spatial niche. CONCLUSIONS: Our results suggest that the tumor microenvironment is involved in shaping the tumor peripheral niche by stimulating the enhanced proliferation that is characteristic for this zone.

Retzius-sparing robot-assisted laparoscopic radical prostatectomy: functional and early oncologic results in aggressive and locally advanced prostate cancer.

BACKGROUND: Retzius-sparing robot-assisted laparoscopic radical prostatectomy (rsRARP) allows entire prostatectomy procedure via the pouch of Douglas. In low- and intermediate-risk prostate cancer (PCa) there is level 1 evidence that the Retzius-sparing approach impacts early continence recovery. Since specific data on aggressive and locally advanced cancer is lacking and avoiding rsRARP is presently suggested, we investigated urinary and sexual recovery, perioperative complications and early oncologic outcomes after rsRARP in this particular cohort. METHODS: Prospectively collected data of 50 consecutive men (median age 66 years) with high-risk PCa who underwent rsRARP in a single institution was analysed retrospectively. The follow-up for all patients was 12 months after surgery. RESULTS: 3 vs. 12 months after surgery, 82% vs. 98% of men used no pad or one safety pad and 50% vs. 72% used no pad. 89% of patients did not observe a decline of continence if postoperative radiotherapy was carried out. Considering the 17 preoperatively potent patients who underwent bi- or unilateral nerve-sparing surgery, 41% reported their first sexual intercourse within 1 year after rsRARP. 84% of patients had ≥pT3a disease and 42% positive surgical margins. A lymphadenectomy was done in 94% of patients with a median lymph node removal of 15 and lymph node metastasis in 13%. 34% underwent adjuvant radiotherapy and 22% adjuvant androgen deprivation therapy (ADT). 1-year recurrence-free survival was 96%, including 25% of patients on adjuvant or salvage ADT. CONCLUSIONS: RsRARP in high-risk PCa is feasible and results in excellent continence rates, even after postoperative radiotherapy. The potency rates are promising but need further clarification in larger cohorts. Reliable oncologic outcomes require longterm follow-up and are awaited.

Patients under 4 years old treated with overhead extension for isolated femoral fractures - lessons learned concerning parents' satisfaction.

BACKGROUND: Conservative options are the standard for treatment of femoral fractures for patients under the age of 4 years. We investigated possible factors influencing the satisfaction of the parents in order to improve their experience. PATIENTS: We analyzed 42 cases of children under the age of 4 years treated with overhead extension therapy (OHE) for femoral fracture. METHODS: Our protocol requires transition to spica cast treatment (SCT) and discharge from the hospital after the initial 10-day OHE. X-rays were analyzed for fracture healing. A pseudonymized questionnaire was sent to the parents in order to evaluate their experiences during the treatment. RESULTS: The nature of the fracture was explained to 73.3% of the parents in a way that was "understandable and in detail". However, 23.3% stated that "many questions were not answered". Seventy percent of parents noticed behavioral abnormalities during treatment, and 63.3% reported treatment-specific problems. Additionally, 86.7% of parents were satisfied with the therapy outcome, 80% were content with the type of therapy, and 73.3% would choose OHE again. We found a high Spearman correlation between general satisfaction and parents who felt well informed. There was also a strong correlation between high general satisfaction and the opportunity for any problems to be discussed and addressed during the medical rounds. DISCUSSION: The reasons for nonsatisfaction were primarily due to communication problems. CONCLUSION: Thorough evaluation during medical rounds, communication with healthcare professionals and care provided by the nurses affects the contentment of the families significantly.

Multiparametric MRI fusion-guided biopsy for the diagnosis of prostate cancer.

PURPOSE OF REVIEW: To discuss the timing, benefits, limitations and current controversies of multiparametric magnet resonance imaging (mpMRI) combined with fusion-guided biopsy and consider how additional incorporation of multivariable risk stratification might further improve prostate cancer diagnosis. RECENT FINDINGS: MpMRI has been proven advantageous over standard practice for biopsy-naïve men and men with previous biopsy in large prospective studies providing level 1b evidence. Upfront multivariable risk stratification followed by or combined with mpMRI further improves diagnostic accuracy. Regarding active surveillance, mpMRI in combination with fusion biopsy can support initial candidate selection and may help to monitor disease progression. mpMRI and fusion biopsy, however, do not spare failure and conflicting data exists to what extend (systematic) biopsies can be omitted. SUMMARY: Integration of mpMRI into the diagnostic pathway for prostate cancer is beneficial; yet more prospective and randomized data is needed to establish reliable procedure standards after mpMRI acquisition.

Multiparametric MRI and MRI/TRUS Fusion Guided Biopsy for the Diagnosis of Prostate Cancer.

Purpose of this chapter To demonstrate the timing, benefits, limitations and current controversies of multiparametric magnet resonance imaging (mpMRI) combined with fusion guided biopsy and consider how additional incorporation of multivariable risk stratification might further improve prostate cancer (PC) diagnosis. Recent findings MpMRI has been shown to add important information to the diagnostic pathway for prostate cancer. Fusion biopsy has also shown advantages in comparison to standard practice for biopsy-naïve men and men with previous biopsy in large prospective studies providing level 1b evidence. Adding upfront multivariable risk stratification followed by or combined with mpMRI diagnostic accuracy can further be improved. Regarding active surveillance (AS), mpMRI in combination with fusion biopsy can support initial candidate selection and may help to monitor disease progression. However, mpMRI and fusion biopsy are not without failure and conflicting data exists to what extend (systematic) biopsies can be omitted. Summary The integration of mpMRI into the diagnostic pathway for PC can add important information for further decision making, yet more prospective and randomized data is needed to establish reliable procedure standards after mpMRI acquisition.

PD-L1 as a Urine Biomarker in Renal Cell Carcinoma-A Case Series and Proof-of-Concept Study.

BACKGROUND: Renal cell carcinoma (RCC) is among the most lethal urologic malignancies once metastatic. Current treatment approaches for metastatic RCC (mRCC) involve immune checkpoint inhibitors (ICIs) that target the PD-L1/PD-1 axis. High PD-L1 expression in tumor tissue has been identified as a negative prognostic factor in RCC. However, the role of PD-L1 as a liquid biomarker has not yet been fully explored. Herein, we analyze urine levels of PD-L1 in mRCC patients before and after either ICI therapy or surgical intervention, as well as in a series of patients with treatment-naïve RCC. PATIENTS AND METHODS: The mid-stream urine of patients with mRCC (n = 4) or treatment-naïve RCC, i.e., prior to surgery from two centers (cohort I, n = 49: cohort II, n = 29) was analyzed for PD-L1 by ELISA. The results from cohort I were compared to a control group consisting of patients treated for non-malignant urologic diseases (n = 31). In the mRCC group, urine PD-L1 levels were measured before and after tumor nephrectomy (n = 1) or before and after ICI therapy (n = 3). Exosomal PD-L1 in the urine was analyzed in selected patients by immunoblotting. RESULTS: A strong decrease in urine PD-L1 levels was found after tumor nephrectomy or following systemic treatment with ICIs. In patients with treatment-naïve RCC (cohort I), urine PD-L1 levels were significantly elevated in the RCC group in comparison to the control group (median 59 pg/mL vs. 25.7 pg/mL, p = 0.011). PD-L1 urine levels were found to be elevated, in particular, in low-grade RCCs in cohorts I and II. Exosomal PD-L1 was detected in the urine of a subset of patients. CONCLUSION: In this proof-of-concept study, we show that PD-L1 can be detected in the urine of RCC patients. Urine PD-L1 levels were found to correlate with the treatment response in mRCC patients and were significantly elevated in treatment-naïve RCC patients.

Immune landscape of renal cell carcinoma with metastasis to the pancreas.

INTRODUCTION: Clear cell Renal Cell Carcinoma (ccRCC) has a poor prognosis once metastatic. However, certain metastatic sites have been reported to have a different impact on the patient prognosis. For example, patients with pancreatic metastases have a much more favorable prognosis than those with metastases to other organs. The biological basis for this observation remains poorly understood. The aim of this study was to characterize the immune landscape of pancreatic metastases and the corresponding primary tumors in order to identify possible immunological features that correlate with disease biology. PATIENTS AND METHODS: A detailed assessment of immune cell populations was performed using a total of 1,700 microscopic images from ccRCCs from 11 patients, their corresponding pancreatic metastases and ccRCCs from 10 patients without pancreatic metastases. Tumor specimens were stained for CD45, CD8, CD163 and FOXP3 and the densities of the respective immune cells were assessed semiquantitatively in the intratumoral and extratumoral compartment. Multispectral imaging was performed in selected tumors. RESULTS: We found that pancreatic metastases show the lowest intratumoral infiltration with CD8+ cytotoxic T lymphocytes of all tumor specimens analyzed. The frequency of CD8+ lymphocytes was on 1.9 fold lower in pancreatic metastases (median density 8.3 cells per field of view [FOV] = 1.23 mm2) when compared to the corresponding primary tumor (15.6 cells per FOV, P = 0.0002) and more than 3-fold lower when compared to ccRCCs without pancreatic metastases (27.2 cells per FOV, P = 0.0012). There was also a significantly reduced intratumoral infiltration with immunosuppressive FOXP3+ lymphocytes in pancreatic metastases (2.6 cells per FOV, P = 0.009) and corresponding primary tumors (2 cells per FOV, P = 0.028) when compared to ccRCCs without pancreatic metastases (5.6 cells per FOV). CONCLUSIONS: In this proof-of-concept study, we show that pancreatic metastases of ccRCC present with unique immunological features including a low intratumoral density of CD8+ and FOXP3+ lymphocytes. The low counts of CD8+ and FOXP3+ lymphocytes may reflect less aggressive features of ccRCC with pancreatic metastasis that may result in a more favorable patient prognosis.

Long-Term Survival of Patients with Stage T1N0M1 Renal Cell Carcinoma.

Metastatic renal cell carcinoma (RCC) is among the most lethal urological malignancies. However, small, localized RCCs (≤7 cm, stage T1) have an excellent prognosis. There is a rare patient subgroup diagnosed with synchronous distant metastasis (T1N0M1), of which very little is known in terms of survival outcomes and underlying disease biology. Herein, we examined the long-term survival of 27 patients with clear cell RCC (ccRCC) stage T1N0M1 in comparison to 18 patients without metastases (T1N0M0). Tumor tissue was stained by immunohistochemistry for CD8+ tumor infiltrating lymphocytes (TILs). As expected, patients with stage T1N0M1 showed a significantly worse median cancer specific survival (CSS; 2.8 years) than patients with stage T1N0M0 (17.7 years; HR 0.077; 95% CI, 0.022-0.262). However, eight patients (29.6%) with ccRCC stage T1N0M1 survived over five years, and three of those patients (11.1%) survived over a decade. Some of these patients benefitted from an intensified, multimodal treatment including metastasis-directed therapy. The number of CD8+ TILs was substantially higher in stage T1N0M1 ccRCCs than in stage T1N0M0 ccRCCs, suggesting a more aggressive tumor biology. In conclusion, long-term survival is possible in patients with ccRCC stage T1N0M1, with some patients benefitting from an intensified, multimodal treatment approach.

Same-day repeatability and Between-Sequence reproducibility of Mean ADC in PI-RADS lesions.

PURPOSE: This study aimed to assess repeatability after repositioning (inter-scan), intra-rater, inter-rater and inter-sequence variability of mean apparent diffusion coefficient (ADC) measurements in MRI-detected prostate lesions. METHOD: Forty-three patients with suspicion for prostate cancer were included and received a clinical prostate bi-/multiparametric MRI examination with repeat scans of the T2-weighted and two DWI-weighted sequences (ssEPI and rsEPI). Two raters (R1 and R2) performed single-slice, 2D regions of interest (2D-ROIs) and 3D-segmentation-ROIs (3D-ROIs). Mean bias, corresponding limits of agreement (LoA), mean absolute difference, within-subject coefficient of variation (CoV) and repeatability/reproducibility coefficient (RC/RDC) were calculated. Bradley & Blackwood test was used for variance comparison. Linear mixed models (LMM) were used to account for multiple lesions per patient. RESULTS: Inter-scan repeatability, intra-rater and inter-sequence reproducibility analysis of ADC showed no significant bias. 3D-ROIs demonstrated significantly less variability than 2D-ROIs (p < 0.01). Inter-rater comparison demonstrated small significant systematic bias of 57 × 10-6 mm2/s for 3D-ROIs (p < 0.001). Intra-rater RC, with the lowest variation, was 145 and 189 × 10-6 mm2/s for 3D- and 2D-ROIs, respectively. For 3D-ROIs of ssEPI, RCs and RDCs were 190-198 × 10-6 mm2/s for inter-scan, inter-rater and inter-sequence variation. No significant differences were found for inter-scan, inter-rater and inter-sequence variability. CONCLUSIONS: In a single-scanner setting, single-slice ADC measurements showed considerable variation, which may be lowered using 3D-ROIs. For 3D-ROIs, we propose a cut-off of âˆ¼ 200 × 10-6 mm2/s for differences introduced by repositioning, rater or sequence effects. The results suggest that follow-up measurements should be possible by different raters or sequences.

Digital Spatial Profiling Identifies the Tumor Periphery as a Highly Active Biological Niche in Clear Cell Renal Cell Carcinoma.

Clear cell renal cell carcinoma (ccRCC) is characterized by a high degree of intratumoral heterogeneity (ITH). Besides genomic ITH, there is considerable functional ITH, which encompasses spatial niches with distinct proliferative and signaling activities. The full extent of functional spatial heterogeneity in ccRCC is incompletely understood. In the present study, a total of 17 ccRCC tissue specimens from different sites (primary tumor, n = 11; local recurrence, n = 1; distant metastasis, n = 5) were analyzed using digital spatial profiling (DSP) of protein expression. A total of 128 regions of interest from the tumor periphery and tumor center were analyzed for the expression of 46 proteins, comprising three major signaling pathways as well as immune cell markers. Results were correlated to clinico-pathological variables. The differential expression of granzyme B was validated using conventional immunohistochemistry and was correlated to the cancer-specific patient survival. We found that a total of 37 proteins were differentially expressed between the tumor periphery and tumor center. Thirty-five of the proteins were upregulated in the tumor periphery compared to the center. These included proteins involved in cell proliferation, MAPK and PI3K/AKT signaling, apoptosis regulation, epithelial-to-mesenchymal transition, as well as immune cell markers. Among the most significantly upregulated proteins in the tumor periphery was granzyme B. Granzyme B upregulation in the tumor periphery correlated with a significantly reduced cancer-specific patient survival. In conclusion, this study highlights the unique cellular contexture of the tumor periphery in ccRCC. The correlation between granzyme B upregulation in the tumor periphery and patient survival suggests local selection pressure for aggressive tumor growth and disease progression. Our results underscore the potential of spatial biology for biomarker discovery in ccRCC and cancer in general.

Impact of Surgeon's Experience in Rigid versus Elastic MRI/TRUS-Fusion Biopsy to Detect Significant Prostate Cancer Using Targeted and Systematic Cores.

Multiparametric magnetic resonance imaging (mpMRI) and MRI/ultrasound fusion-targeted prostate biopsy (FB) have excellent sensitivity in detecting significant prostate cancer (sPC). FB platforms can be distinguished by rigid (RTB) or elastic image registration (ETB). We compared RTB and ETB by analyzing sPC detection rates of both RTB and ETB at different stages of the surgeons' learning curve. Patients undergoing RTB between 2015-2017 (n = 502) were compared to patients undergoing ETB from 2017-2019 (n = 437). SPC detection rates were compared by Chi-square-test on patient-basis. Combination of transperineal systematic biopsy and each TB served as reference and sub-analyses were performed for different grades of surgeon's experience. In the RTB subgroup, 233 men (46%) had sPC, compared to 201 (46%) in the ETB subgroup. RTB alone detected 94% of men with sPC and ETB 87% (p = 0.02). However, for at least intermediate-experienced surgeons (>100 FB), no differences occurred between RTB and ETB. In the total cohort, at least intermediate-experienced surgeons detected significantly more sPC (10%, p = 0.008) than novices. Thus, targeted transperineal MRI/TRUS-FB with a RTB registration system showed a similar sPC detection rate to ETB in experienced surgeons but a superior sPC detection rate to ETB in the total cohort. Low-experienced surgeons seem to benefit from RTB.

Pseudoprospective Paraclinical Interaction of Radiology Residents With a Deep Learning System for Prostate Cancer Detection: Experience, Performance, and Identification of the Need for Intermittent Recalibration.

OBJECTIVES: The aim of this study was to estimate the prospective utility of a previously retrospectively validated convolutional neural network (CNN) for prostate cancer (PC) detection on prostate magnetic resonance imaging (MRI). MATERIALS AND METHODS: The biparametric (T2-weighted and diffusion-weighted) portion of clinical multiparametric prostate MRI from consecutive men included between November 2019 and September 2020 was fully automatically and individually analyzed by a CNN briefly after image acquisition (pseudoprospective design). Radiology residents performed 2 research Prostate Imaging Reporting and Data System (PI-RADS) assessments of the multiparametric dataset independent from clinical reporting (paraclinical design) before and after review of the CNN results and completed a survey. Presence of clinically significant PC was determined by the presence of an International Society of Urological Pathology grade 2 or higher PC on combined targeted and extended systematic transperineal MRI/transrectal ultrasound fusion biopsy. Sensitivities and specificities on a patient and prostate sextant basis were compared using the McNemar test and compared with the receiver operating characteristic (ROC) curve of CNN. Survey results were summarized as absolute counts and percentages. RESULTS: A total of 201 men were included. The CNN achieved an ROC area under the curve of 0.77 on a patient basis. Using PI-RADS ≥3-emulating probability threshold (c3), CNN had a patient-based sensitivity of 81.8% and specificity of 54.8%, not statistically different from the current clinical routine PI-RADS ≥4 assessment at 90.9% and 54.8%, respectively ( P = 0.30/ P = 1.0). In general, residents achieved similar sensitivity and specificity before and after CNN review. On a prostate sextant basis, clinical assessment possessed the highest ROC area under the curve of 0.82, higher than CNN (AUC = 0.76, P = 0.21) and significantly higher than resident performance before and after CNN review (AUC = 0.76 / 0.76, P ≤ 0.03). The resident survey indicated CNN to be helpful and clinically useful. CONCLUSIONS: Pseudoprospective paraclinical integration of fully automated CNN-based detection of suspicious lesions on prostate multiparametric MRI was demonstrated and showed good acceptance among residents, whereas no significant improvement in resident performance was found. General CNN performance was preserved despite an observed shift in CNN calibration, identifying the requirement for continuous quality control and recalibration.

A Platform and Multisided Market for Translational, Software-Defined Medical Procedures in the Operating Room (OP 4.1): Proof-of-Concept Study.

BACKGROUND: Although digital and data-based technologies are widespread in various industries in the context of Industry 4.0, the use of smart connected devices in health care is still in its infancy. Innovative solutions for the medical environment are affected by difficult access to medical device data and high barriers to market entry because of proprietary systems. OBJECTIVE: In the proof-of-concept project OP 4.1, we show the business viability of connecting and augmenting medical devices and data through software add-ons by giving companies a technical and commercial platform for the development, implementation, distribution, and billing of innovative software solutions. METHODS: The creation of a central platform prototype requires the collaboration of several independent market contenders, including medical users, software developers, medical device manufacturers, and platform providers. A dedicated consortium of clinical and scientific partners as well as industry partners was set up. RESULTS: We demonstrate the successful development of the prototype of a user-centric, open, and extensible platform for the intelligent support of processes starting with the operating room. By connecting heterogeneous data sources and medical devices from different manufacturers and making them accessible for software developers and medical users, the cloud-based platform OP 4.1 enables the augmentation of medical devices and procedures through software-based solutions. The platform also allows for the demand-oriented billing of apps and medical devices, thus permitting software-based solutions to fast-track their economic development and become commercially successful. CONCLUSIONS: The technology and business platform OP 4.1 creates a multisided market for the successful development, implementation, distribution, and billing of new software solutions in the operating room and in the health care sector in general. Consequently, software-based medical innovation can be translated into clinical routine quickly, efficiently, and cost-effectively, optimizing the treatment of patients through smartly assisted procedures.

Mutations in TP53 or DNA damage repair genes define poor prognostic subgroups in primary prostate cancer.

BACKGROUND: Mutations in DNA damage repair genes, in particular genes involved in homology-directed repair, define a subgroup of men with prostate cancer with a more unfavorable prognosis but a therapeutic vulnerability to PARP inhibition. In current practice, mutational testing of prostate cancer patients is commonly done late i.e., when the tumor is castration resistant. In addition, most sequencing panels do not include TP53, one of the most crucial tumor suppressor genes in human cancer. In this proof-of-concept study, we sought to extend the clinical use of these molecular markers by exploring the early prognostic impact of mutations in TP53 and DNA damage repair genes in men with primary, nonmetastatic prostate cancer undergoing radical prostatectomy (RPX). METHODS: Tumor specimens from a cohort of 68 RPX patients with intermediate (n = 11, 16.2%) or high-risk (n = 57, 83.8%) disease were analyzed by targeted next generation sequencing using a 37 DNA damage repair and checkpoint gene panel including TP53. Sequencing results were correlated to clinicopathologic variables as well as PSA persistence or time to PSA failure. In addition, the distribution of TP53 and DNA damage repair gene mutations was analyzed in three large publicly available datasets (TCGA, MSKCC and SU2C). RESULTS: Of 68 primary prostate cancers analyzed, 23 (33.8%) were found to harbor a mutation in either TP53 (n = 12, 17.6%) or a DNA damage repair gene (n = 11, 16.2%). The vast majority of these mutations (22 of 23, 95.7%) were detected in primary tumors from patients with high-risk features. These mutations were mutually exclusive in our cohort and additional data mining suggests an enrichment of DNA damage repair gene mutations in TP53 wild-type tumors. Mutations in either TP53 or a DNA damage repair gene were associated with a significantly worse prognosis after RPX. Importantly, the presence of TP53/DNA damage repair gene mutations was an independent risk factor for PSA failure or PSA persistence in multivariate Cox regression models. CONCLUSION: TP53 or DNA damage repair gene mutations are frequently detected in primary prostate cancer with high-risk features and define a subgroup of patients with an increased risk for PSA failure or persistence after RPX. The significant adverse impact of these alterations on patient prognosis may be exploited to identify men with prostate cancer who may benefit from a more intensified treatment.

Imaging of Prostate Cancer.

BACKGROUND: Prostate cancer is the most common type of solid tumor in men and the second most common cause of cancer-related death in males in Germany. The conventional strategy for its primary detection, i.e., systematic ultrasound-guided prostate biopsy in men who have elevated PSA levels and/or positive findings on digital rectal examination, fails to reveal all cases. The same is true of the use of conventional computed tomography (CT), magnetic resonance imaging (MRI), and skeletal scintigraphy for the early detection of recurrences and distant metastases. METHODS: This review is based on pertinent publications retrieved by a selective search, including the German clinical practice guideline on prostate cancer and systematic review articles. RESULTS: Prospective multicenter trials have shown that the detection of clinically significant prostate cancer is markedly improved with multiparametric MRI (mpMRI) and MR/TRUS fusion biopsy (TRUS = transrectal ultrasonography), compared to conventional systematic biopsy. A recent Cochrane review showed that the rate of overdiagnosis of low-risk prostate cancer was reduced with mpMRI and MR/TRUS fusion biopsy compared with conventional systematic biopsy (95/1000 vs. 139/1000), and that clinically significant prostate cancer was more reliably detected (sensitivity 72% vs. 63%), albeit with slightly lower specificity (96% vs. 100%). Prostate- specific membrane antigen (PSMA) hybrid imaging improves the detection of lymphogenic and bony metastases in patients with high-risk prostate cancer. PSMA hybrid imaging is most commonly used to detect biochemical recurrences. A metaanalysis showed that the detection rate depends on the PSA concentration: 74.1% overall, 33.7% with PSA <0.2 ng/mL, and 91.7% with PSA ≥= 2.0 ng/mL. CONCLUSION: The appropriate use of mpMRI and MR/TRUS fusion biopsy improves the initial detection of prostate cancer as well as the assessment of the prognosis. PSMA hybrid imaging is useful for the staging of high-risk patients and for the detection of recurrences. These methods are now recommended in the German clinical practice guideline on prostate cancer as well as in guidelines from other countries.

Comparison of single-scanner single-protocol quantitative ADC measurements to ADC ratios to detect clinically significant prostate cancer.

BACKGROUND: Mean ADC has high predictive value for the presence of clinically significant prostate cancer (sPC). Measurement variability is introduced by different scanners, protocols, intra-and inter-patient variation. Internal calibration by ADC ratios can address such fluctuations however can potentially lower the biological value of quantitative ADC determination by being sensitive to deviations in reference tissue signal. PURPOSE: To better understand the predictive value of quantitative ADC measurements in comparison to internal reference ratios when measured in a single scanner, single protocol setup. MATERIALS AND METHODS: 284 consecutive patients who underwent 3 T MRI on a single scanner followed by MRI-transrectal ultrasound fusion biopsy were included. A board-certified radiologist retrospectively reviewed all MRIs blinded to clinical information and placed regions of interest (ROI) on all focal lesions and the following reference regions: normal-appearing peripheral zone (PZNL) and transition zone (TZNL), the urinary bladder (BLA), and right and left internal obturator muscle (RIOM, LIOM). ROI-based mean ADC and ADC ratios to the reference regions were compared regarding their ability to predict the aggressiveness of prostate cancer. Spearman's rank correlation coefficient was used to estimate the correlation between ADC parameters, Gleason score (GS) and ADC ratios. The primary endpoint was presence of sPC, defined as a GS ≥ 3 + 4. Univariable and multivariable logistic regression models were constructed to predict sPC. Receiver operating characteristics curves (ROC) were used for visualization; DeLong test was used to evaluate the differences of the area under the curve (AUC). Bias-corrected AUC values and corresponding 95 %-CI were calculated using bootstrapping with 100 bootstrap samples. RESULTS: After exclusion of patients who received prior treatment, 259 patients were included in the final cohort of which 220 harbored 351 MR lesions. Mean ADC and ADC ratios demonstrated a negative correlation with the GS. Mean ADC had the strongest correlation with ρ of -0.34, followed by ADCratioPZNL (ρ=-0.32). All ADC parameters except ADCratioLIOM (p = 0.07) were associated with sPC p<0.05). Mean ADC and ADCratioPZNL had the highest ROC AUC of all parameters (0.68). Multivariable models with mean ADC improve predictive performance. CONCLUSIONS: A highly standardized single-scanner mean ADC measurement could not be improved upon using any of the single ADC ratio parameters or combinations of these parameters in predicting the aggressiveness of prostate cancer.

The Value of Prostate-specific Antigen Density for Prostate Imaging-Reporting and Data System 3 Lesions on Multiparametric Magnetic Resonance Imaging: A Strategy to Avoid Unnecessary Prostate Biopsies.

BACKGROUND: Multiparametric magnetic resonance imaging (mpMRI) has excellent sensitivity in detecting significant prostate cancer (sPC). Nevertheless, uncertainty exists regarding the management of Prostate Imaging-Reporting and Data System (PI-RADS) 3 lesions. OBJECTIVE: To investigate whether PI-RADS 3 lesions in combination with clinical parameters, especially prostate-specific antigen density (PSAD), can be used to exclude sPC. DESIGN, SETTING, AND PARTICIPANTS: A total of 455 consecutive biopsy-naïve men underwent MRI-guided transperineal prostate fusion biopsy at our department between 2017 and 2018. We identified 101 patients who had exclusively one or more PI-RADS 3 lesions on mpMRI. sPC was defined as intermediate- and high-risk PC (according to the D'Amico risk classification). OUTCOME MEASURES AND STATISTICAL ANALYSIS: Univariate logistic regression analysis was performed to test different clinical factors as predictors of sPC in men with PI-RADS 3 lesions. The probability of sPC prediction was calculated for different PSAD thresholds. RESULTS AND LIMITATIONS: Among patients with PI-RADS 3 lesions, PSAD was a significant predictor of sPC (p = 0.005). For a PI-RADS score of 3 the probability of excluding sPC was 85% (86/101), which increased to 98% (42/43) when combined with PSAD <0.1 ng/ml/ml. CONCLUSIONS: Inclusion of PSAD < 0.1 ng/ml/ml in the strategy for biopsy-naïve patients with equivocal mpMRI findings would allow a reduction in prostate biopsies in 43% (43/101) of cases at the cost of missing a very small number (2%, 1/43) of intermediate-risk PCs. PATIENT SUMMARY: At high-volume tertiary care centers with significant experience in prostate multiparametric magnetic resonance imaging, immediate biopsies could be safely omitted for men with lesions with a Prostate Imaging-Reporting and Data System score of 3 and prostate-specific antigen density of PSAD < 0.1 ng/ml/ml. Any decision to omit an immediate biopsy should be associated with close monitoring.

Measured Multipoint Ultra-High b-Value Diffusion MRI in the Assessment of MRI-Detected Prostate Lesions.

OBJECTIVES: The aim of this study was to assess quantitative ultra-high b-value (UHB) diffusion magnetic resonance imaging (MRI)-derived parameters in comparison to standard clinical apparent diffusion coefficient (SD-ADC-2b-1000, SD-ADC-2b-1500) for the prediction of clinically significant prostate cancer, defined as Gleason Grade Group greater than or equal to 2. MATERIALS AND METHODS: Seventy-three patients who underwent 3-T prostate MRI with diffusion-weighted imaging acquired at b = 50/500/1000/1500s/mm2 and b = 100/500/1000/1500/2250/3000/4000 s/mm2 were included. Magnetic resonance lesions were segmented manually on individual sequences, then matched to targeted transrectal ultrasonography/MRI fusion biopsies. Monoexponential 2-point and multipoint fits of standard diffusion and of UHB diffusion were calculated with incremental b-values. Furthermore, a kurtosis fit with parameters Dapp and Kapp with incremental b-values was obtained. Each parameter was examined for prediction of clinically significant prostate cancer using bootstrapped receiver operating characteristics and decision curve analysis. Parameter models were compared using Vuong test. RESULTS: Fifty of 73 men (age, 66 years [interquartile range, 61-72]; prostate-specific antigen, 6.6 ng/mL [interquartile range, 5-9.7]) had 64 MRI-detected lesions. The performance of SD-ADC-2b-1000 (area under the curve, 0.82) and SD-ADC-2b-1500 (area under the curve, 0.82) was not statistically different (P = 0.99), with SD-ADC-2b-1500 selected as reference. Compared with the reference model, none of the 19 tested logistic regression parameter models including multipoint and 2-point UHB-ADC, Dapp, and Kapp with incremental b-values of up to 4000 s/mm2 outperformed SD-ADC-2b-1500 (all P's > 0.05). Decision curve analysis confirmed these results indicating no higher net benefit for UHB parameters in comparison to SD-ADC-2b-1500 in the clinically important range from 3% to 20% of cancer threshold probability. Net reduction analysis showed no reduction of MR lesions requiring biopsy. CONCLUSIONS: Despite evaluation of a large b-value range and inclusion of 2-point, multipoint, and kurtosis models, none of the parameters provided better predictive performance than standard 2-point ADC measurements using b-values 50/1000 or 50/1500. Our results suggest that most of the diagnostic benefits available in diffusion MRI are already represented in an ADC composed of one low and one 1000 to 1500 s/mm2 b-value.