Novel imaging techniques reshape the landscape in high-risk prostate cancers

Comparison of PET/CT and MRI in the Diagnosis of Bone Metastasis in Prostate Cancer Patients: A Network Analysis of Diagnostic Studies

BACKGROUND

Accurate diagnosis of bone metastasis status of prostate cancer (PCa) is becoming increasingly more important in guiding local and systemic treatment. Positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) have increasingly been utilized globally to assess the bone metastases in PCa. Our meta-analysis was a high-volume series in which the utility of PET/CT with different radioligands was compared to MRI with different parameters in this setting.

MATERIALS AND METHODS

Three databases, including Medline, Embase, and Cochrane Library, were searched to retrieve original trials from their inception to August 31, 2019 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. The methodological quality of the included studies was assessed by two independent investigators utilizing Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). A Bayesian network meta-analysis was performed using an arm-based model. Absolute sensitivity and specificity, relative sensitivity and specificity, diagnostic odds ratio (DOR), and superiority index, and their associated 95% confidence intervals (CI) were used to assess the diagnostic value.

RESULTS

Forty-five studies with 2,843 patients and 4,263 lesions were identified. Network meta-analysis reveals that 68Ga-labeled prostate membrane antigen (68Ga-PSMA) PET/CT has the highest superiority index (7.30) with the sensitivity of 0.91 and specificity of 0.99, followed by 18F-NaF, 11C-choline, 18F-choline, 18F-fludeoxyglucose (FDG), and 18F-fluciclovine PET/CT. The use of high magnetic field strength, multisequence, diffusion-weighted imaging (DWI), and more imaging planes will increase the diagnostic value of MRI for the detection of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT was performed in the detection of bone metastasis on patient-based level (sensitivity, 0.94 vs. 0.91; specificity, 0.94 vs. 0.96; superiority index, 4.43 vs. 4.56).

CONCLUSIONS

68Ga-PSMA PET/CT is recommended for the diagnosis of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT should be performed in the detection of bone metastasis.

Detection and Characterization of Musculoskeletal Cancer Using Whole-Body Magnetic Resonance Imaging

Whole-body magnetic resonance imaging (WB-MRI) is gradually being integrated into clinical pathways for the detection, characterization, and staging of malignant tumors including those arising in the musculoskeletal (MSK) system. Although further developments and research are needed, it is now recognized that WB-MRI enables reliable, sensitive, and specific detection and quantification of disease burden, with clinical applications for a variety of disease types and a particular application for skeletal involvement. Advances in imaging techniques now allow the reliable incorporation of WB-MRI into clinical pathways, and guidelines recommending its use are emerging. This review assesses the benefits, clinical applications, limitations, and future capabilities of WB-MRI in the context of other next-generation imaging modalities, as a qualitative and quantitative tool for the detection and characterization of skeletal and soft tissue MSK malignancies.

Whole Body MRI and oncology: recent major advances

MRI is a very attractive approach for tumour detection and oncological staging with its absence of ionizing radiation, high soft tissue contrast and spatial resolution. Less than 10 years ago the use of Whole Body MRI (WB-MRI) protocols was uncommon due to many limitations, such as the forbidding acquisition times and limited availability. This decade has marked substantial progress in WB-MRI protocols. This very promising technique is rapidly arising from the research world and is becoming a commonly used examination for tumour detection due to recent technological developments and validation of WB-MRI by multiple studies and consensus papers. As a result, WB-MRI is progressively proposed by radiologists as an efficient examination for an expanding range of indications. As the spectrum of its uses becomes wider, radiologists will soon be confronted with the challenges of this technique and be urged to be trained in order to accurately read and report these examinations. The aim of this review is to summarize the validated indications of WB-MRI and present an overview of its most recent advances. This paper will briefly discuss how this examination is performed and which are the recommended sequences along with the future perspectives in the field.

Whole Body MRI and oncology: recent major advances

MRI is a very attractive approach for tumour detection and oncological staging with its absence of ionizing radiation, high soft tissue contrast and spatial resolution. Less than 10 years ago the use of Whole Body MRI (WB-MRI) protocols was uncommon due to many limitations, such as the forbidding acquisition times and limited availability. This decade has marked substantial progress in WB-MRI protocols. This very promising technique is rapidly arising from the research world and is becoming a commonly used examination for tumour detection due to recent technological developments and validation of WB-MRI by multiple studies and consensus papers. As a result, WB-MRI is progressively proposed by radiologists as an efficient examination for an expanding range of indications. As the spectrum of its uses becomes wider, radiologists will soon be confronted with the challenges of this technique and be urged to be trained in order to accurately read and report these examinations. The aim of this review is to summarize the validated indications of WB-MRI and present an overview of its most recent advances. This paper will briefly discuss how this examination is performed and which are the recommended sequences along with the future perspectives in the field.

Impact of five-tiered Gleason grade groups on prognostic prediction in clinical stage T3 prostate cancer undergoing high-dose-rate brachytherapy

BACKGROUND

We evaluated a five-tiered Gleason grade groups arising from the 2014 International Society of Urological Pathology consensus conference on prognostic prediction in clinical stage T3a (extracapsular invasion) and T3b (seminal vesicle involvement) prostate cancer undergoing high-dose-rate brachytherapy (HDR-BT).

METHODS

From November 2003 to December 2012, 283 patients with stage T3 prostate cancer received HDR-BT and external beam radiation therapy (EBRT) with long-term androgen deprivation therapy (ADT). Of these, 203 (72%) and 80 (28%) patients had stage T3a and T3b disease, respectively. The mean dose to 90% of the planning target volume was 7.5 Gy/fraction of HDR-BT. After five fractions, EBRT with 10 fractions of 3 Gy was administered. All patients first underwent ≥6 months of neoadjuvant ADT, and adjuvant ADT continued for 36 months. Median follow-up was 74 months from the start of radiotherapy.

RESULTS

The 10-year biochemical recurrence (BCR) -free rate for stage T3a and T3b disease was 79% and 64%, respectively (P = 0.0083). The 10-year cancer-specific survival (CSS) rate for stage T3a and T3b was 96% and 91%, respectively (P = 0.0305). Although grade groups ≥4 were independent predictors for BCR in cT3a patients (P = 0.0270), they failed to significantly predict prostate cancer-specific mortality (PCSM) among cT3a patients. Among cT3b patients, grade group 5 was a significant predictor of both BCR (P = 0.0017) and PCSM (P = 0.0233). Among stage T3a patients, no significant difference existed in 10-year CSS between grade groups 5 and 4 (94% vs 97%, P = 0.3960). In contrast, grade group 5 had a significantly worse outcome in 10-year CSS than grade group 4 among stage T3b patients (74% vs 100%, P = 0.0350).

CONCLUSIONS

Stage T3a patients with grade groups 4/5 and stage T3b with grade group 4 had fairly low PCSM risk. Approximately one of four patients among stage T3b patients with grade group 5 showed PCSM after combined HDR-BT and EBRT with long-term ADT. Stage T3b patients with grade group 5 may have a greater risk for PCSM.

Whole body MRI (WB-MRI) assessment of metastatic spread in prostate cancer: Therapeutic perspectives on targeted management of oligometastatic disease

OBJECTIVES

To determine the proportion of prostate cancer (PCa) patients with oligometastatic disease (≤3 synchronous lesions) using whole body magnetic resonance imaging with diffusion-weighted imaging (WB-MRI/DWI). To determine the proportion of patients with nodal disease confined within currently accepted target areas for extended lymph node dissection (eLND) and pelvic external beam radiation therapy (EBRT).

SUBJECTS AND METHODS

Two radiologists reviewed WB-MRI/DWI studies in 96 consecutive newly diagnosed metastatic PCa patients; 46 patients with newly diagnosed castration naive PCa (mHNPC) and 50 patients with first appearance of metastasis during monitoring for non-metastatic castration resistant PCa (M0 to mCRPC). The distribution of metastatic deposits was assessed and the proportions of patients with oligometastatic disease and with LN metastases located within eLND and EBRT targets were determined.

RESULTS

Twenty-eight percent of mHNPC and 50% of mCPRC entered the metastatic disease with ≤3 sites. Bone metastases (BM) were identified in 68.8% patients; 71.7% of mHNPC and 66% mCRPC patients. Most commonly involved areas were iliac bones and lumbar spine. Enlarged lymph nodes (LN) were detected in 68.7% of patients; 69.6% of mHNPC and 68.0% of mCRPC. Most commonly involved areas were para-aortic, inter-aortico-cava, and external iliac areas. BM and LN were detected concomitantly in 41% of mHNPC and 34% of mCRPC. Visceral metastases were detected in 6.7%. Metastatic disease was confined to LN located within the accepted boundaries of eLND or pelvic EBRT target areas in only ≤25% and ≤30% of patients, respectively.

CONCLUSIONS

Non-invasive mapping of metastatic landing sites in PCa using WB-MRI/DWI shows that 28% of the mHNPC patients, and 52% of the mCRPC can be classified as oligometastatic, thus challenging the concept of metastatic targeted therapy. More than two thirds of metastatic patients have LN located outside the usually recommended targets of eLND and pelvic EBRT. Prophylactic or salvage treatments of these sole areas in patients with high-risk prostate cancer may not prevent the emergence of subsequent metastases. Prostate 76:1024-1033, 2016. © 2016 Wiley Periodicals, Inc.

Apparent diffusion coefficient measurement by diffusion weighted magnetic resonance imaging is a useful tool in differentiating renal tumors

BACKGROUND

To determine the clinical value of apparent diffusion coefficient (ADC) measurement by diffusion weighted magnetic resonance imaging (DW-MRI) in differentiating renal tumors.

METHODS

Electronic databases were searched using combinations of keywords and free words relating to renal tumor, ADC and DW-MRI. Based on carefully selected inclusion and exclusion criteria, relevant case-control studies were identified and the related clinical data was acquired. Statistical analyses were performed using STATA 12.0 (Stata Corporation, College station, TX).

RESULTS

Sixteen case-control studies were ultimately included in the present meta-analysis. These 16 high quality studies contained a combined total of 438 normal renal tissues and 832 renal tumor lesions (597 malignant and 235 benign). The results revealed that ADC values of malignant renal tumor tissues were markedly lower than normal renal tissues and benign renal tumor tissues. ADC values of benign renal tumor tissues were also significantly lower than normal renal tissue.

CONCLUSIONS

ADC measurement by DW-MRI provided clinically useful information on the internal structure of renal tumors and could be an important radiographic index for differentiation of malignant renal tumors from benign renal tumors.

Prognostic Utility of PET in Prostate Cancer

Many standard nonimaging-based prediction tools exist for prostate cancer. However, these tools may be limited in individual cases and need updating based on the improved understanding of the underlying complex biology of the disease and the emergence of the novel targeted molecular imaging methods. A new platform of automated predictive tools that combines the independent molecular, imaging, and clinical information can contribute significantly to patient care. Such a platform will also be of interest to regulatory agencies and payers as more emphasis is placed on supporting those interventions that have quantifiable and significant beneficial impact on patient outcome.

Positron emission tomography image-guided drug delivery: current status and future perspectives

Positron emission tomography (PET) is an important modality in the field of molecular imaging, which is gradually impacting patient care by providing safe, fast, and reliable techniques that help to alter the course of patient care by revealing invasive, de facto procedures to be unnecessary or rendering them obsolete. Also, PET provides a key connection between the molecular mechanisms involved in the pathophysiology of disease and the according targeted therapies. Recently, PET imaging is also gaining ground in the field of drug delivery. Current drug delivery research is focused on developing novel drug delivery systems with emphasis on precise targeting, accurate dose delivery, and minimal toxicity in order to achieve maximum therapeutic efficacy. At the intersection between PET imaging and controlled drug delivery, interest has grown in combining both these paradigms into clinically effective formulations. PET image-guided drug delivery has great potential to revolutionize patient care by in vivo assessment of drug biodistribution and accumulation at the target site and real-time monitoring of the therapeutic outcome. The expected end point of this approach is to provide fundamental support for the optimization of innovative diagnostic and therapeutic strategies that could contribute to emerging concepts in the field of “personalized medicine”. This review focuses on the recent developments in PET image-guided drug delivery and discusses intriguing opportunities for future development. The preclinical data reported to date are quite promising, and it is evident that such strategies in cancer management hold promise for clinically translatable advances that can positively impact the overall diagnostic and therapeutic processes and result in enhanced quality of life for cancer patients.

One-step TNM staging of high-risk prostate cancer using magnetic resonance imaging (MRI): toward an upfront simplified "all-in-one" imaging approach?

BACKGROUND

Multiparametric magnetic resonance imaging (mpMRI) is the standard for local prostate cancer (PCa) staging. Whole-body MRI (wbMRI) has shown capabilities for metastatic screening. This study assesses the feasibility and value of an all-in-one AJCC TNM staging of PCa during a unique MRI session combining mpMRI and wbMRI.

METHODS

Thirty consecutive patients with "high-risk" PCa prospectively underwent mpMRI of the prostate and wbMRI, in addition to (99m) Tc bone scan (BS), completed with standard X-rays (±TXR) and contrast enhanced CT for distant staging. For the statistical analysis, a "best valuable comparator" (BVC) combining a panel review of all available baseline and follow-up imaging, biological, and clinical data was used to adjudicate lymph node and bone metastatic status.

RESULTS

Prostate mpMRI was analyzed using ESUR guidelines. Sensitivity of BS ± TXR combined with CT and of wbMRI for detecting metastases (bones or nodes) was 85% and 100%, respectively, and specificity was 88% and 100%, respectively. For the overall staging of the patients as being either N0M0 or having disease extension beyond the prostate, wbMRI was superior to the combination of BS and CT (improvement in all ROC characteristics and of AUC by 13.6% (95% CI: +0.7% to +26.5%, P = 0.039)). The main limitation is the limited number of patients.

CONCLUSIONS

AJCC M and N staging using wbMRI is feasible during the same imaging session as mpMRI performed for T staging, in less then one hour. wbMRI outperforms BS ± TXR and abdomino-pelvic CT work up for discriminating subsets of patients with or without distant spread of the cancer.

[Potential of PET/MRI for diagnosis of prostate cancer]

CLINICAL/METHODICAL ISSUE

A present goal is to improve detection and staging of prostate cancer using innovative imaging technology such as PET/MRI.

STANDARD RADIOLOGICAL METHODS

The modality of choice for detection of prostate cancer is multiparametric MRI. Furthermore, PET/CT is used, in particular, for the detection and staging of distant metastases and recurrent disease. For assessment of bone metastases, the method most commonly used is bone scintigraphy.

METHODICAL INNOVATIONS

The development of a simultaneous hybrid PET/MRI system is the last great "fusion" of the known cross-sectional image modalities. In addition, synthesis of new, innovative tracers such as (18)F-FACBC or (68)Ga-PSMA allows more specific detection of prostate cancer.

PERFORMANCE

Hybrid PET/MRI imaging has the potential to replace conventional imaging techniques in the future.

ACHIEVEMENTS

The method is just starting the broad application. Clinical studies must be expanded in order to substantiate the additional value of the method.

PRACTICAL RECOMMENDATIONS

Currently, there is still a low distribution situation, since it is a new and cost-intensive method. At the same time, there is still no consistent solution for reimbursement. The importance in practice first rises by clarifying the payment situation and further demonstration of the method's benefit by larger studies.

Impact of 18F-fluoride PET in patients with known prostate cancer: initial results from the National Oncologic PET Registry

Under Medicare's Coverage with Evidence Development policy, PET using (18)F-sodium fluoride (NaF PET) to identify osseous metastasis became a covered service if prospective registry data were collected. The National Oncologic PET Registry (NOPR) developed a NaF PET registry built on the foundation of its prior registry for PET with (18)F-FDG. Men with prostate cancer represented 72% of the cases.

METHODS

Prospective data before and after NaF PET were collected from referring and interpreting physicians. The analysis set consisted of consenting men age 65 y or older with prostate cancer undergoing NaF PET for initial staging (IS, n = 1,024), suspected first osseous metastasis (FOM, n = 1,997), or suspected progression of osseous metastasis (POM, n = 510).

RESULTS

Referring physicians indicated that if NaF PET were not available, other advanced imaging (body CT, MR imaging, or (18)F-FDG PET) would be their plan in about half of the cases. After NaF PET, the postimaging plan was revised to treatment in 77%, 52%, and 71% for IS, FOM, and POM, respectively. When intended management was classified as either treatment or nontreatment, the overall change in intended management ranged from 44% to 52% and from 12% to 16% if no effect was assumed for those cases with pre-PET plans for other imaging (imaging-adjusted impact). Interpreting physicians recorded definite findings of bone metastasis in 14%, 29%, and 76% for IS, FOM, and POM, respectively. The intended care patterns varied widely across indication and scan abnormality category combinations.

CONCLUSION

NaF PET has high overall impact, principally related to its effect on replacing intended use of other advanced imaging. Its imaging-adjusted impact was similar to that observed with (18)F-FDG PET for restaging or suspected recurrence in other cancer types.