Advances in Imaging and Diagnosis of Prostate Cancer

Tofts models have failed to produce reliable quantitative markers for prostate cancer. We examined the differences between prostate zones and lesion PI-RADS categories and grade group (GG) using regions of interest drawn in tumor and normal-appearing tissue for a two-compartment uptake (2CU) model (including plasma volume (v_p), plasma flow (F_p), permeability surface area product (PS), plasma mean transit time (MTT_p), capillary transit time (T_c), extraction fraction (E), and transfer constant (K_trans)) and exponential (amplitude (A), arrival time (t₀), and enhancement rate (α)), sigmoidal (amplitude (A₀), center time relative to arrival time (A₁ − T₀), and slope (A₂)), and empirical mathematical models, and time to peak (TTP) parameters fitted to high temporal resolution (1.695 s) DCE-MRI data. In 25 patients with 35 PI-RADS category 3 or higher tumors, we found F_p and α differed between peripheral and transition zones. Parameters F_p, MTT_p, T_c, E, α, A₁ − T₀, and A₂ and TTP all showed associations with PI-RADS categories and with GG in the PZ when normal-appearing regions were included in the non-cancer GG. PS and K_trans were not associated with any PI-RADS category or GG. This pilot study suggests early enhancement parameters derived from ultrafast DCE-MRI may become markers of prostate cancer. Full article

Background: Physiological PSMA expression in the cells of the proximal renal tubules and consecutive radiopharmaceutical binding and retention could potentially lead to radioligand-therapy-induced nephrotoxicity. Thus, patients with metastatic castration-resistant prostate cancer undergo ^99mTc-Mercaptoacetyltriglycine (MAG3) renal scintigraphy to assess kidney function and to exclude renal obstruction as part of their workup for PSMA-targeted radioligand therapy (RLT). ^99mTc-MAG-3 renal scintigraphy often requires an additional visit to the nuclear medicine department and patients spend 30–90 min in the department, which is inconvenient and takes up camera time. In addition, the patients are subjected to a baseline ⁶⁸Ga-PSMA PET/CT to assess for PSMA-positive disease prior to targeted radioligand therapy. The aim of this retrospective cross-sectional study was to compare ^99mTc-MAG-3-based split renal function (SRF) with ⁶⁸Ga-PSMA-derived SRF. Methods: This retrospective cross-sectional study included 28 patients with histologically proven metastatic castration-resistant prostate cancer (mCRPC) who received 177Lu-PSMA617. A comparison between the split renal function using ⁶⁸Ga-PSMA PET/CT and the ^99mTc-MAG-3-derived split renal function was carried out in 56 kidneys (n = 56). The SRF on ⁶⁸Ga-PSMA was calculated using the volume and the average standard uptake value (SUVmean) within each VOI calculated as previously described by Roser et al.: SRF = (VOLUME_right) ∗ SUVmean_right/(VOLUME_right ∗ SUVmean_right + VOLUME_left ∗ SUVmean_left). Paired tests and correlation coefficients were used to compare ⁶⁸Ga-PSMA and ^99mTc-MAG-3. A visual comparison of kidney morphology on both studies was also performed. Results: The median SRF of the right kidney was 49.9% (range: 3–91%) using ⁶⁸Ga-PSMA PET/CT and 50.5% (range: 0–94%) with ^99mTc-MAG3 scintigraphy. Notably, there was a strong correlation between SRF measurements obtained from PSMA and ^99mTcMAG3, with a Pearson correlation coefficient of 0.957 (p < 0.001). Both ^99mTc-MAG3 and ⁶⁸Ga-PSMA PET/CT studies identified morphological renal abnormalities; there were nine hydronephrotic kidneys, four shrunken kidneys and one obstructed kidney, and there was a strong positive correlation between ⁶⁸Ga-PSMA kidney morphology and ^99mTcMAG3 renal scintigraphy kidney morphology, with a correlation coefficient of 0.93. Conclusions: PSMA-derived split function demonstrated a high correlation with renal function assessed on diuretic ^99mTc-MAG3 renograms. PET-derived split renal function may, therefore, be considered an alternative to diuretic renogram-based split function. Furthermore, both ^99mTc-MAG3 and ⁶⁸Ga-PSMA PET/CT studies identified morphological renal abnormalities such as hydronephrosis, shrunken and obstructed kidneys. This correlation underscores the potential utility of ⁶⁸Ga-PSMA imaging as a valuable tool for assessing kidney morphology as an alternative to renogram split function in clinical practice. Full article

Background: Currently, there are no studies evaluating the feasibility of a prostate biopsy approach in men undergoing a kidney transplant (KT). Owing to this evidence, we planned a retrospective population-based study to evaluate our experience of a transrectal prostate biopsy (TR-PB) approach and studied the impact on the complication rate and outcomes in patients undergoing KT with suspected prostate cancer (PCa). Methods: We collected data from KT patients who underwent PB with a transrectal approach. One week and two weeks after the PB, patients’ information was collected regarding possible complications during the post-biopsy period. Results: A total of 121 patients were included in this study. Among them, Group 1 was composed of 59 patients undergoing TR-PB with an ultrasound (US) standard technique, and Group 2 consisted of 62 patients undergoing TR-PB with an MRI-US cognitive technique. We observed a 28.9% Clavien–Dindo grade ≤ 2 of early side effect rates (mostly rectal bleeding and other minor hematuria), with a very low rate of hospital re-admission for acute urinary retention (3.3%); only one man required hospitalization for rectal bleeding, and there were no major complications. Conclusions: We can affirm that TR-PB can be a safe procedure with a low risk of severe complications when performed by skilled specialists with a standardized procedural pathway. Full article

This study aimed to investigate the association between the ⁶⁸Ga- or ¹⁸F-radiolabeled prostate-specific membrane antigen (PSMA) tracer expression, represented by the maximum standardised uptake value (SUV_max) of the dominant intraprostatic lesion, and biochemical recurrence (BCR) in primary prostate cancer (PCa) patients prior to robot-assisted radical prostatectomy (RARP). This was a retrospective, multi-centre cohort study of 446 patients who underwent [⁶⁸Ga]Ga-PSMA-11 (n = 238) or [¹⁸F]DCFPyL (n = 206) Positron Emission Tomography/Computed Tomography (PET/CT) imaging prior to RARP. SUV_max was measured in the dominant intraprostatic PCa lesions. [¹⁸F]DCFPyL patients were scanned 60 ([¹⁸F]DCFPyL-60; n = 106) or 120 ([¹⁸F]DCFPyL-120; n = 120) minutes post-injection of a radiotracer and were analysed separately. To normalise the data, SUV_max was log transformed for further analyses. During a median follow-up of 24 months, 141 (30.4%) patients experienced BCR. Log₂SUV_max was a significant predictor for BCR (p < 0.001). In the multivariable analysis accounting for these preoperative variables: initial prostate-specific antigen (PSA), radiologic tumour stage (mT), the biopsy International Society of Urological Pathology grade group (bISUP) and the prostate imaging and reporting data system (PI-RADS), Log₂SUV_max was found to be an independent predictor for BCR in [⁶⁸Ga]Ga-PSMA-11 (HR 1.32, p = 0.04) and [¹⁸F]DCFPyL-120 PET/CT scans (HR 1.55, p = 0.04), but not in [¹⁸F]DCFPyL-60 ones (HR 0.92, p = 0.72). The PSMA expression of the dominant intraprostatic lesion proved to be an independent predictor for BCR in patients with primary PCa who underwent [⁶⁸Ga]Ga-PSMA-11 or [¹⁸F]DCFPyL-120 PET/CT scans, but not in those who underwent [¹⁸F]DCFPyL-60 PET/CT scans. Full article

Diffusion-weighted images of the prostate can suffer from a “hazy” background in low signal-intensity areas. We hypothesize that enhanced image processing (EIP) using complex averaging reduces artifacts, noise, and distortion in conventionally acquired diffusion-weighted images and synthesized high b-value images, thus leading to higher image quality and better detection of potentially malignant lesions. Conventional DWI trace images with a b-value of 1000 s/mm² (b1000), calculated images with a b-value of 2000 s/mm² (cb2000), and ADC maps of 3T multiparametric prostate MRIs in 53 patients (age 68.8 ± 10 years) were retrospectively evaluated. Standard images were compared to images using EIP. In the standard images, 36 lesions were detected in the peripheral zone and 20 in the transition zone. In 13 patients, EIP led to the detection of 8 additional lesions and the upgrading of 6 lesions; 6 of these patients were diagnosed with prostate carcinoma Gleason 7 or 8. EIP improved qualitative ratings for overall image quality and lesion detectability. Artifacts were significantly reduced in the cb2000 images. Quantitative measurements for lesion detectability expressed as an SI ratio were significantly improved. EIP using complex averaging led to image quality improvements in acquired and synthesized DWI, potentially resulting in elevated diagnostic accuracy and management changes. Full article

A negative multiparametric magnetic resonance imaging (mpMRI)-guided prostate biopsy in patients with suspected prostate cancer (PC) results in clinical uncertainty, as the biopsy can be false negative. The clinical challenge is to determine the optimal follow-up and to select patients who will benefit from repeat biopsy. In this study, we evaluated the rate of significant PC (sPC, Gleason score ≥7) and PC detection in patients who received a follow-up mpMRI/ultrasound-guided biopsy for persistent PC suspicion after a negative mpMRI/ultrasound-guided biopsy. We identified 58 patients at our institution that underwent repeat targeted biopsy in case of PI-RADS lesions and systematic saturation biopsy between 2014 and 2022. At the initial biopsy, the median age was 59 years, and the median prostate specific antigen level was 6.7 ng/mL. Repeat biopsy after a median of 18 months detected sPC in 3/58 (5%) patients and Gleason score 6 PC in 11/58 (19%). Among 19 patients with a downgraded PI-RADS score at the follow-up mpMRI, none had sPC. In conclusion, men with an initial negative mpMRI/ultrasound-guided biopsy had a high likelihood of not harboring sPC at repeat biopsy (95%). Due to the small size of the study, further research is recommended. Full article

Purpose: Surgical margin status in radical prostatectomy (RP) specimens is an established predictive indicator for determining biochemical prostate cancer recurrence and disease progression. Predicting positive surgical margins (PSMs) is of utmost importance. We sought to perform a meta-analysis evaluating the diagnostic utility of a high clinical tumor stage (≥3) on magnetic resonance imaging (MRI) for predicting PSMs. Method: A systematic search of the PubMed, Embase databases, and Cochrane Library was performed, covering the interval from 1 January 2000 to 31 December 2022, to identify relevant studies. The Quality Assessment of Diagnostic Accuracy Studies 2 method was used to evaluate the studies’ quality. A hierarchical summary receiver operating characteristic plot was created depicting sensitivity and specificity data. Analyses of subgroups and meta-regression were used to investigate heterogeneity. Results: This meta-analysis comprised 13 studies with 3924 individuals in total. The pooled sensitivity and specificity values were 0.40 (95% CI, 0.32–0.49) and 0.75 (95% CI, 0.69–0.80), respectively, with an area under the receiver operating characteristic curve of 0.63 (95% CI, 0.59–0.67). The Higgins I2 statistics indicated moderate heterogeneity in sensitivity (I2 = 75.59%) and substantial heterogeneity in specificity (I2 = 86.77%). Area, prevalence of high Gleason scores (≥7), laparoscopic or robot-assisted techniques, field strength, functional technology, endorectal coil usage, and number of radiologists were significant factors responsible for heterogeneity (p ≤ 0.01). Conclusions: T stage on MRI has moderate diagnostic accuracy for predicting PSMs. When determining the treatment modality, clinicians should consider the factors contributing to heterogeneity for this purpose. Full article