MRI-guided in-bore biopsy for prostate cancer: what does the evidence say? A case series of 554 patients and a review of the current literature.

PURPOSE: To review our experience with MRI-guided in-bore prostate biopsy (MRGB) and present a review of the literature on MRGB. METHODS: A retrospective review of patients presenting for MRGB between 2013 and 2018. Diagnostic and biopsy MRI scans were reviewed to collect data on scan dates, procedure times, characteristics of MRI targets (PI-RADS™ score, target size, ADC value and location). A review of the literature on MRGB for the period 2013-2018 was performed. RESULTS: 607 targets in 554 men were biopsied. Overall and significant cancer detection rate were 80% and 55% at a patient level, and 76 and 59% at the target level, respectively. Prostate cancer (CaP) detection in men with prior negative biopsy was 60% while 50% of men on active surveillance were upgraded to clinically significant disease (CSD). Lesion location did not predict for presence of CaP or CSD. PI-RADS™ score, age and PSAD were predictors of CSD at biopsy on multivariate analysis. Literature review identified 23 reports reporting on MRGB cohorts (~ 4000 patients). Overall cancer detection ranged from 23 to 74% and CSD in 63% overall. CaP detection in PI-RADS™ 3 targets was substantially lower in our series and the literature than for PI-RADS™ 4-5 targets. CONCLUSIONS: MRGB in PI-RADS™ 3-5 targets yields high rates of cancer diagnosis. High detection rates are also seen in men with prior negative biopsy and AS cohorts. PI-RADS™ score, age and PSAD can reliably predict CSD detection. The number of published series is small and the role of MRGB in PI-RADS™ 3 targets needs further study.

The use of 68 Ga-PSMA PET CT in men with biochemical recurrence after definitive treatment of acinar prostate cancer.

INTRODUCTION: Early localisation of disease recurrence after definitive treatment of prostate cancer is vital to determine suitability for salvage treatment. Our aim was to further investigate the relationship between prostate specific antigen (PSA) level and detection of suspected cancer recurrence using 68  Ga-PSMA PET/CT in patients with biochemical recurrence after radical prostatectomy (RP) or radiotherapy, particularly at low PSA levels. METHODS: This retrospective single tertiary referral institution cohort study of men reviewed the results of 68  Ga-PSMA PET/CT scans for investigation of post RP and post radiotherapy PSA recurrence following primary treatment of prostate cancer. We included men with suspected recurrent prostate cancer based on an elevated post treatment PSA level. The data collected analyzed the relationship of the pre-scan PSA level to the probability of a positive scan finding for recurrent prostate cancer. RESULTS: Of the cohort of 532 men, 425 had a previous RP and 107 had prior radiotherapy. The median PSA of the RP group was 0.59 ng/mL and 5.8 ng/mL in the radiotherapy group. In the post RP cohort, the detection rate of 68  Ga-PSMA PET/CT was 11.3% for PSA 0.01 to <0.2 ng/mL, 26.6% for PSA 0.2 to <0.5 ng/mL, 53.3% for PSA 0.5 to <1 ng/mL, 79.1% for PSA 1 to <2 ng/mL and 95.5% for PSA ≥2. Lymph node metastasis post RP was identified in 68% of men with suspected disease recurrence. In the post radiotherapy cohort the detection rate was 33.3% for PSA 0.01 to <0.5 ng/mL, 71.4% for PSA 0.5 to <1 ng/mL, 93.3% for PSA 1 to <2 ng/mL and 100% for PSA ≥2. Local recurrence after radiotherapy was suspected in 71% of the cohort and 40% had suspected lymph node metastasis. CONCLUSIONS: To our knowledge, this is largest cohort study of detection rates of 68  Ga-PSMA PET/CT in patients with biochemical recurrence after definitive treatment of prostate cancer, including patients with PSA <0.5 and in a post radiotherapy cohort. Detection of suspected recurrent disease outside the pelvis at low PSA levels will influence the decision for salvage treatment options.

Location of Prostate Cancers Determined by Multiparametric and MRI-Guided Biopsy in Patients With Elevated Prostate-Specific Antigen Level and at Least One Negative Transrectal Ultrasound-Guided Biopsy.

OBJECTIVE: The purpose of this article is to identify histopathologically proven prostate cancer locations using MRI followed by MRI-guided biopsy in patients with elevated prostate-specific antigen (PSA) levels and at least one negative transrectal ultrasound (TRUS)-guided biopsy session. Our hypothesis is that in this patient group most cancers are located in the anterior portion of the prostate. This may have implications for the biopsy strategy regarding the location of sampling. MATERIALS AND METHODS: This retrospective study consisted of 872 consecutive men who had undergone MRI-guided prostate biopsy. Inclusion criteria were PSA level greater than or equal to 4 ng/mL, one or more negative TRUS-guided biopsy session, the presence of suspicious lesions on previous multiparametric MRI, and prostate cancer histopathologically proven by MRI-guided biopsy. Thereafter, the location of intermediate- or high-risk cancers and cancers with a maximum cancer core length of 6 mm or longer were determined. The proportion of cancer locations was compared using a chi-square test. One-way ANOVA analyses were performed to compare patient characteristics. RESULTS: Results were presented on both a patient and lesion basis because a single patient can have multiple lesions. In total, 176 of 872 patients met the inclusion criteria. Prostate cancer was detected in 202 of 277 (73%) suspicious lesions. In total, 76% of patients had cancer of the transition zone and anterior fibromuscular stroma. Peripheral zone cancers were found in 30% of the patients, and 6% had cancers in both zones. In 70% of cases (141/202; 95%, CI, 63-76%), lesions were located anteriorly; this included 75% (132/176; 95%, CI, 69-81%) of patients. Intermediate- or high-risk prostate cancer was found in 93% (128/138; 95%, CI, 88-96%) of patients. Of these patients, 73% (94/128; 95%, CI, 66-81%) had anterior involvement. Cancers with a maximum cancer core length of 6 mm or more were more likely to be located in the anterior part of the prostate than were cancers with a core length of less than 6 mm (66% vs 6%). Most cancers 58% (102/176; 95% CI, 51-65%) were found in the mid prostate. Anterior involvement of prostate cancer detected by MRI-guided biopsy was statistically significantly (p = 0.04) higher in patients with two or more negative TRUS-guided biopsy sessions (79%) than in those with one negative TRUS-guided biopsy session (55%). CONCLUSION: Anterior involvement was high (76%) in patients with an elevated PSA level and one or more negative TRUS-guided biopsy session, and the majority of these cancers (93%) were intermediate or high risk.

Multiparametric MRI in the diagnosis of prostate cancer - a generational change.

BACKGROUND: Whether a general practitioner (GP) should order prostate-specific antigen (PSA) testing for a patient is a question that has been unresolved for 25 years. The authors suggest that the image-based diagnostic pathway, rather than the biopsy-driven diagnostic pathway, will answer this question. OBJECTIVE: This article describes, in non-technical terms, the methodology of prostate imaging with multiparametric magnetic resonance imaging (mpMRI), and targeted biopsies of lesions within the prostate. The benefits and risks of the new technology are discussed. DISCUSSION: Accurate anatomical and functional imaging of the prostate gland, and diagnosis of significant (intermediate- and high-risk) prostate cancer, is now becoming available in Australia. However, there is still a learning curve in the implementation of this technology.

The role of magnetic resonance imaging in the diagnosis and management of prostate cancer.

BACKGROUND: The diagnosis of prostate cancer has long been plagued by the absence of an imaging tool that reliably detects and localises significant tumours. Recent evidence suggests that multi-parametric MRI could improve the accuracy of diagnostic assessment in prostate cancer. This review serves as a background to a recent USANZ position statement. It aims to provide an overview of MRI techniques and to critically review the published literature on the clinical application of MRI in prostate cancer. TECHNICAL ASPECTS: The combination of anatomical (T2-weighted) MRI with at least two of the three functional MRI parameters - which include diffusion-weighted imaging, dynamic contrast-enhanced imaging and spectroscopy - will detect greater than 90% of significant (moderate to high risk) tumours; however MRI is less reliable at detecting tumours that are small (<0.5 cc), low grade (Gleason score 6) or in the transitional zone. The higher anatomical resolution provided by 3-Tesla magnets and endorectal coils may improve the accuracy, particularly in primary tumour staging. SCREENING: The use of mpMRI to determine which men with an elevated PSA should undergo biopsy is currently the subject of two large clinical trials in Australia. MRI should be used with caution in this setting and then only in centres with established uro-radiological expertise and quality control mechanisms in place. There is sufficient evidence to justify using MRI to determine the need for repeat biopsy and to guide areas in which to focus repeat biopsy. IMAGE-DIRECTED BIOPSY: MRI-directed biopsy is an exciting concept supported by promising early results, but none of the three proposed techniques have so far been proven superior to standard biopsy protocols. Further evidence of superior accuracy and core-efficiency over standard biopsy is required, before their costs and complexities in use can be justified. TREATMENT SELECTION AND PLANNING: When used for primary-tumour staging (T-staging), MRI has limited sensitivity for T3 disease, but its specificity of greater than 95% may be useful in men with intermediate-high risk disease to identify those with advanced T3 disease not suitable for nerve sparing or for surgery at all. MRI appears to be of value in planning dosimetry in men undergoing radiotherapy, and in guiding selection for and monitoring on active surveillance.

Why and Where do We Miss Significant Prostate Cancer with Multi-parametric Magnetic Resonance Imaging followed by Magnetic Resonance-guided and Transrectal Ultrasound-guided Biopsy in Biopsy-naïve Men?

BACKGROUND: Knowledge of significant prostate (sPCa) locations being missed with magnetic resonance (MR)- and transrectal ultrasound (TRUS)-guided biopsy (Bx) may help to improve these techniques. OBJECTIVE: To identify the location of sPCa lesions being missed with MR- and TRUS-Bx. DESIGN, SETTING, AND PARTICIPANTS: In a referral center, 223 consecutive Bx-naive men with elevated prostate specific antigen level and/or abnormal digital rectal examination were included. Histopathologically-proven cancer locations, Gleason score, and tumor length were determined. INTERVENTION: All patients underwent multi-parametric MRI and 12-core systematic TRUS-Bx. MR-Bx was performed in all patients with suspicion of PCa on multi-parametric MRI (n=142). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Cancer locations were compared between MR- and TRUS-Bx. Proportions were expressed as percentages, and the corresponding 95% confidence intervals were calculated. RESULTS AND LIMITATIONS: In total, 191 lesions were found in 108 patients with sPCa. From these lesion 74% (141/191) were defined as sPCa on either MR- or TRUS-Bx. MR-Bx detected 74% (105/141) of these lesions and 61% (86/141) with TRUS-Bx. TRUS-Bx detected more lesions compared with MR-Bx (140 vs 109). However, these lesions were often low risk (39%). Significant lesions missed with MR-Bx most often had involvement of dorsolateral (58%) and apical (37%) segments and missed segments with TRUS-Bx were located anteriorly (79%), anterior midprostate (50%), and anterior apex (23%). CONCLUSIONS: Both techniques have difficulties in detecting apical lesions. MR-Bx most often missed cancer with involvement of the dorsolateral part (58%) and TRUS-Bx with involvement of the anterior part (79%). PATIENT SUMMARY: Both biopsy techniques miss cancer in specific locations within the prostate. Identification of these lesions may help to improve these techniques.