Five‐year trends of bone scan and prostate‐specific membrane antigen positron emission tomography utilization in prostate cancer: A retrospective review in a private centre

Clinical Positron Emission Tomography/Computed Tomography: Quarter-Century Transformation of Prostate Cancer Molecular Imaging

Although positron emission tomography/computed tomography (PET/CT) underwent rapid growth during the last quarter-century, becoming a new standard-of-care for imaging most cancer types, CT and bone scan remained the gold standard for patients with prostate cancer. This occurred as 2-fluorine-18-fluoro-2-deoxy-d-glucose was perceived to have a limited role owing to low sensitivity in many patients. A resurgence of interest occurred with the use of fluorine-18-sodium-fluoride PET/CT as a replacement for bone scintigraphy, and then choline, fluciclovine, and dihydrotestosterone (DHT) PET/CT as prostate "specific" radiotracers. The last decade, however, has seen a true revolution with the meteoric rise of prostate-specific membrane antigen PET/CT.

Meta-analysis of 18 F-PSMA-1007 PET/CT, 18 F-FDG PET/CT, and 68Ga-PSMA PET/CT in diagnostic efficacy of prostate Cancer

OBJECTIVE

To compare 18 F-PSMA-1007 PET/CT, 18 F-FDG PET/CT and 68Ga-PSMA PET/CT in the diagnostic value of prostate cancer.

METHOD

The Chinese and foreign databases, such as Pubmed, Cochrane Library, Embase, CNKI, VIP, Wanfang, etc., were systematically searched within the period from the establishment of the database to June 1, 2022. Clinical studies related to the diagnosis of prostate cancer by methods such as 18 F-PSMA-1007 PET/CT, 18 F-FDG PET/CTCT, 68Ga-PSMA PET/CT, were researched. Two (2) investigators independently screened literatures, extracted data, and assessed the risk of bias when these data were included in the studies with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). Review Manager5.4, Stata 14.0, and Meta-disc 1.4 software were used for meta-analysis to compare the efficacy of different methods in the diagnose of prostate cancer.

RESULTS

Twenty-seven (27) studies, including 2891 subjects were included in our study. Meta-analysis results showed that the pooled sensitivities of 18 F-PSMA-1007 PET/CT, 18 F-FDG PET/CT, and 68Ga-PSMA PET/CT were 0.912 (95%CI: 0.883-0.936), 0.748 (95%CI: 0.698-0.795), and 0.916 (95%CI: 0.896-0.934), respectively; the pooled specification were 0.878 (0.844-0.907), 0.639 (95%CI: 0.589-0.687), and 0.734 (95%CI: 0.685-0.779), respectively; the positive likelihood ratios were 6.335 (95%CI: 4.288-9.357), 2.282 (95%CI: 1.497-3.477), and 3.593 (95%CI: 2.986-4.323), respectively; the negative likelihood ratios were 0.878 (95%CI: 0.844-0.907), 0.374 (95%CI: 0.280-0.499), and 0.110 (95%CI: 0.083-0.144), respectively; the diagnostic odds ratios were 65.125 (95%CI: 34.059-124.53), 7.094 (95%CI: 4.091-12.301), and 29.722 (95%CI: 20.141-43.863), respectively; the positive posterior probability was 64%, 38%, and 62%, respectively; the area under the SPOC curve was 0.95 (95%CI: 0.93-0.97), 0.81 (95%CI: 0.78-0.84), and 0.96 (95%CI: 0.92-0.98), respectively. The funnel plots indicated that there was no significant publication bias in the included literatures.

CONCLUSION

The current evidences showed that 18 F-PSMA-1007 PET/CT and 68Ga-PSMA PET/CT had higher diagnostic efficacy of prostate cancer compared with 18 F-FDG PET/CT, among which 68Ga-PSMA PET/CT was slightly higher in the sensitivity of the diagnosis of prostate cancer, while 18 F-PSMA-1007 PET/CT may have higher efficacy in specificity and confirmed positive rate. Due to the limitations of the quality of the included samples and literatures, the above conclusions should be further validated by expanding the sample size and improving the quality.

ACR Appropriateness Criteria® Pretreatment Detection, Surveillance, and Staging of Prostate Cancer: 2022 Update

Prostate cancer is second leading cause of death from malignancy after lung cancer in American men. The primary goal during pretreatment evaluation of prostate cancer is disease detection, localization, establishing disease extent (both local and distant), and evaluating aggressiveness, which are the driving factors of patient outcomes such as recurrence and survival. Prostate cancer is typically diagnosed after the recognizing elevated serum prostate-specific antigen level or abnormal digital rectal examination. Tissue diagnosis is obtained by transrectal ultrasound-guided biopsy or MRI-targeted biopsy, commonly with multiparametric MRI without or with intravenous contrast, which has recently been established as standard of care for detecting, localizing, and assessing local extent of prostate cancer. Although bone scintigraphy and CT are still typically used to detect bone and nodal metastases in patients with intermediate- or high-risk prostate cancer, novel advanced imaging modalities including prostatespecific membrane antigen PET/CT and whole-body MRI are being more frequently utilized for this purpose with improved detection rates. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Head-to-Head Comparison of 68Ga-PSMA-11 PET/CT and 99mTc-MDP Bone Scintigraphy for the Detection of Bone Metastases in Patients With Prostate Cancer: A Meta-Analysis

Background: Bone scintigraphy (BS) using 99mTc-MDP remains the recommended imaging modality for the detection of bone metastases in patients with prostate cancer (PCa). However, PET/CT using prostate-specific membrane antigen (PSMA) ligands is increasingly recognized for evaluating disease extent in patients with PCa, including as a possible standalone test in high-risk patients. Objective: To compare the diagnostic performance of 68Ga-PSMA-PET/CT and 99mTc-MDP BS for the detection of bone metastases in patients with PCa. Evidence Acquisition: PubMed, Embase, and Cochrane Library databases were searched through October 2021 for studies reporting a head-to-head comparison of 68Ga-PSMA-PET/CT and 99mTc-MDP BS for the detection of bone metastases in patients with PCa. Only studies with a well-defined reference standard (including various combinations of imaging and/or clinical follow-up) were included. Pooled diagnostic performance was calculated using bivariate random-effects model, and AUC was derived for each test from hierarchical summary ROC analysis. The two tests' complementary roles in identifying bone metastases in patients in whom the other test was negative were summarized. Evidence Synthesis: Six studies with 546 patients were included. The pooled sensitivity and specificity were 98% (95% CI: 94%-99%) and 97% (95% CI: 91%-99%) for 68Ga-PSMA-11 PET/CT versus 83% (95% CI: 69%-91%) and 68% (95% CI: 41%-87%) for 99mTc-MDP BS. The AUC was 0.99 (95% CI: 0.96-1.00) for 68Ga-PSMA-11 PET/CT and 0.85 (95% CI: 0.81-0.87) for 99mTc-MDP BS. In 408 patients from five included studies, 68Ga-PSMA-11 PET/CT correctly identified bone metastases in 43 (22.3%) of 193 patients with negative 99mTc-MDP BS results, whereas 99mTc-MDP BS correctly identified bone metastases in 4 (1.9%) of 210 patients with negative 68Ga-PSMA-11 PET/CT results. Conclusion: On a per-patient basis, 68Ga-PSMA-11 PET/CT has superior diagnostic performance than 99mTc-MDP BS for the detection of prostate cancer bone metastases. Furthermore, 99mTc-MDP BS offers limited additional information in patients with negative 68Ga-PSMA-11 PET/CT results. Clinical impact: According to current evidence, 99mTc-MDP BS is highly unlikely to be additive to 68Ga-PSMA-11 PET/CT in identifying bone metastases in patients with prostate cancer.

Establishing a Provincial Registry for Recurrent Prostate Cancer: Providing Access to PSMA PET/CT in Ontario, Canada

Prostate Specific Membrane Antigen (PSMA) positron emission tomography/computed tomography (PET/CT) is becoming established as a standard of care for the (re)staging of high-risk primary and prostate cancer recurrence after primary therapy. Despite the favorable performance of this imaging modality with high accuracy in disease detection, the availability of PSMA PET/CT varies across jurisdictions worldwide due to variability in the selection of PSMA PET/CT agent, regulatory approvals and funding. In Canada, PSMA based radiopharmaceuticals are still considered investigational new drug (IND), creating limitations in the deployment of these promising imaging agents. While regulatory approval rests with Health Canada, as a single payer health system, funding for Health Canada approved drugs and devices is decided by Provincial Health Ministries. Ontario Health (Cancer Care Ontario) (OH-CCO) is the agency of the Ministry of Health (MOH) in Ontario responsible for making recommendations to the MOH around the organization and funding of cancer services within Ontario (population of 15 million), and the PET Steering Committee of OH-CCO is responsible for providing recommendations on the introduction of new PET radiopharmaceuticals and indications. For Health Canada approved PET radiopharmaceuticals like 18F-FDG, OH-CCO (on behalf of the MOH) provides coverage based on levels of evidence and specific PET Registries are established to aid in real-world evidence collection to inform OH-CCO regarding emerging PET applications. In the case of PSMA PET/CT, adapting this model to an IND PSMA PET/CT agent, 18F-DCFPyL, necessitated the creation of a hybrid Registry-Study model to leverage the existing OH-CCO Registry structure while respecting the need for a Health Canada Clinical Trials Application (CTA) for the deployment of this agent in the province. Within the first 2 years of the registry, over 1700 men have been imaged resulting in a change in management (compared to pre-PET management plans) in over half of the men imaged. In this article, we describe the organization and deployment of the PSMA PET/CT (PREP) Registry throughout the province to provide access for men with suspected prostate cancer recurrence along with key stakeholder perspectives and preliminary results.

The Role of Ga-68-PSMA PET/CT in the Initial Staging of Prostate Cancer - A Single Center 4 Year Experience

Background

Recommended imaging modalities for prostate cancer staging have disappointing sensitivities, whereas [68Ga]-PSMA PET/CT (PET-PSMA) shows promising sensitivities and specificities in the initial management of prostate cancer. Recent studies have revealed that a significant change of management when PET-PSMA was used, with favorable negative predictive values.

Methods

In this retrospective study, we analyzed every PET-PSMA performed in our center for initial staging of intermediate and high-risk prostate cancer. Patients were divided into two groups based on whether imaging modalities other than PET-PSMA were performed. In patients submitted to radical prostatectomy, PET-PSMA findings were compared to histological analysis of the specimen.

Results

PET-PSMA results of 57 patients were gathered, with 77.2% (n=44) having performed CT scan or bone scan (BS) prior to PET-PSMA. Prostate cancer management strategy was changed in 61.4% (n=27), when PET-PSMA was performed following CT and BS. BS and CT results were consistent with PET-PSMA in 43.2% and 44.8%, respectively. In 30 cases, a curative strategy was used based on PET-PSMA findings. PET-PSMA revealed a negative predictive value of 95.2% in 23 patients submitted to radical prostatectomy with bilateral pelvic lymphadenectomy. Prostate SUV values on preoperative PET-PSMA correlated with initial PSA, ISUP grade, PC risk staging and presence of extraprostatic lesions.

Conclusions

PET-PSMA is a key element for prostate cancer staging and management, with high diagnostic accuracy. More prospective studies need to be implemented to determine its role as a first-line staging tool.

Patterns of primary staging for newly diagnosed prostate cancer in the era of prostate specific membrane antigen positron emission tomography: A population-based analysis

INTRODUCTION

There has been a growing body of evidence highlighting the improved sensitivity and specificity for prostate specific membrane antigen (PSMA) positron emission tomography (PET) in advanced prostate cancer imaging. We aimed to assess prostate cancer staging practice patterns in Australia using population-based data.

SUBJECT AND METHODS

We extracted data on men diagnosed with prostate cancer between October 2016 and December 2018 from the Prostate Cancer Outcomes Registry-Victoria (PCOR-Vic). We evaluated trends and comparisons between patients receiving PET/CT (with or without conventional imaging (CImg)), and CImg alone, and analysed imaging modality as predictor of clinical regional node positive disease (cN1 vs cN0/X), metastatic disease (cM1 vs cM0/X), and treatment received.

RESULTS

In total, 6139 patients in the registry had either a staging PET scan (n = 889, 14%), CImg without PET scan (n = 2464, 40%), or no recorded PET or CImg (n = 2786, 45%). The proportion of allimaged patients who received staging PET increased from 19% to 36% from the first to last three-month period, and in the high-risk category the increase was 23-43%. After adjustment for grade group, PET vs CImg-only patients were observed to have a higher proportion of cN1 disease (OR = 2.46, 95% CI: 1.90-3.20) but not cM1 disease (OR = 1.10, 95% CI: 0.84-1.44).

CONCLUSIONS

Our registry data highlights the rapid uptake of PET imaging, particularly in high-risk disease. Based on this data, we highlight the increased diagnosis of nodal disease, thus potentially optimizing patient selection prior to definitive treatment for prostate cancer.

Prostate-specific membrane antigen targeted PET imaging for prostate cancer recurrence

PURPOSE OF REVIEW

Prostate-specific membrane antigen targeted PET imaging (PSMA PET) of biochemically recurrent prostate cancer (BCR) is implemented in routine management in many countries and recommended in European Association of Urology (EAU) and American Society of Clinical Oncology (ASCO) guidelines. Purpose of this review is to summarize recently published evidence of accuracy, management impact, and clinical benefit of PSMA PET in this setting and to state our opinion on the role of PSMA PET in future trials and clinical routine to improve patient outcomes.

RECENT FINDINGS

The past two years saw an increase of evidence supporting superior detection rates and accuracy of PSMA PET versus standard imaging and other PET radiotracers in the localization of BCR. Systematic reviews, prospective trials and large-scale retrospective studies establish PSMA PET as a new benchmark imaging in this setting and demonstrate considerable impact on therapeutic and diagnostic management. Multiple studies have highlighted pitfalls of PSMA PET imaging warranting attention while interpreting these scans.

SUMMARY

PSMA PET is the new imaging method of choice in BCR. Recent evidence shows unprecedented accuracy and high detection rates along with translation into management changes in a majority of patients. However, improvement of oncologic outcome has not been assessed yet. Implementation of PSMA PET into clinical trials and management of BCR will be crucial to demonstrate outcome improvement.

Trends for Stage and Grade Group of Prostate Cancer in the US (2010-2016)

OBJECTIVE

To quantify the yearly prostate cancer incidence per 100,000 men, comparing consecutive years from 2010 through 2016. In the years immediately following the 2011/2012 U.S. Preventive Services Task Force update to prostate specific antigen (PSA) screening guidelines, PSA screening, biopsy, and subsequent prostate cancer diagnosis and definitive local treatment have declined. We performed an analysis of stage and grade at diagnosis for prostate cancer in the US, in the years following the 2011/2012 update.

METHODS/MATERIALS

This was a retrospective study performed using the Surveillance, Epidemiology, and End Results Program data. Inclusion criteria were men ≥ 40 years with prostate cancer diagnosed between the years 2010 and 2016.

RESULTS

In total, 370,865 cases of prostate cancer were analyzed. Overall, the incidence of prostate cancer decreased from 522 to 327 cases per 100,000 persons from 2010 to 2016. Conversely, the rate of metastatic disease increased over this duration from 29 to 37 cases per 100,000 persons (P< .05). In patients ≥70 years, this increase was from 21 to 27 cases per 100,000 persons over the 7 years (P < .05). High-grade disease incidence did not change significantly over the study period, though low-grade disease incidence, (Grade Groups 1 and 2) decreased from 204 and 155 to 116 and 115 cases per 100,000 persons, respectively (P < .05).

CONCLUSIONS

In the years following the 2011/2012 recommendation against PSA screening, fewer localized prostate cancers and more distantly metastatic prostate cancers were diagnosed. Most increases in metastatic disease was among men ≥70 years.

Solitary rib lesions showing prostate-specific membrane antigen (PSMA) uptake in pre-treatment staging 68 Ga-PSMA-11 positron emission tomography scans for men with prostate cancer: benign or malignant?

OBJECTIVES

To determine the proportion of solitary rib lesions on pre-treatment ⁶⁸ Gallium-labelled prostate-specific membrane antigen (PSMA)/computed tomography (CT) scans in men with prostate cancer that are malignant and examine any predictive factors.

PATIENTS AND METHODS

This retrospective single tertiary referral institution cohort study of men reviewed the results of ⁶⁸ Ga-PSMA-11 positron emission tomography (PET)/CT scans performed for primary staging prior to treatment of prostate cancer from July 2014 to September 2019. Men with PSMA uptake outside the prostate in only the rib lesion were included. A solitary rib lesion was considered to be malignant if it increased in size on follow-up imaging. A lesion was considered benign if the prostate-specific antigen (PSA) level remained <0.1 µg/L following a radical prostatectomy (RP), <2 µg/L above nadir following radiotherapy (RT) as per the Phoenix criteria, histology was benign on rib biopsy, or follow-up imaging showed no growth of the rib lesion. If a lesion did not meet these criteria it was considered indeterminate.

RESULTS

A total of 62 men had PSMA uptake in a solitary rib lesion; 54 went on to have RPs and eight underwent RT. In all, 61 of the men (98.4%) met the criteria for a benign rib lesion. Only one man had a false-negative malignant lesion. This man had a rib lesion with a low maximum standardised uptake value (SUV_max ) of 2.21 reported as benign, but the postoperative PSA level was 0.67 µg/L and the rib lesion progressed on follow-up imaging, with development of widespread metastases. Of the benign rib lesions, there were four false positives reported as possible metastases. Three had percutaneous rib biopsies, two of which came back with benign histology and one was indeterminate. The indeterminate biopsy patient had a RP and his postoperative PSA level was <0.1 µg/L. A total of 43 (69.4%) men with benign rib lesions had a SUV_max greater than the SUV_max of the malignant lesion.

CONCLUSION

To our knowledge, this is the first cohort study of men with PSMA-avid solitary rib lesions on pre-treatment ⁶⁸ Ga-PSMA PET/CT staging scans for prostate cancer. Our results indicate that the vast majority of these lesions have low-intensity uptake and are benign. Intervention to confirm this is not usually required.

Does bone scintigraphy still have a role in the era of 68 Ga-PSMA PET/CT in prostate cancer?

OBJECTION

We aimed to evaluate the role of bone scintigraphy (BS) which has long been the imaging modality of choice in prostate cancer (PCa) and performed a head-to-head comparison between BS, BS + SPECT/CT and 68 Ga-PSMA-PET/CT, for the detection of bone metastasis of PCa.

METHODS

We evaluated 138 PCa patients who underwent BS and 68 Ga-PSMA PET/CT and SPECT/CT of 102 of 138 patients. Images were interpreted retrospectively and areas of abnormally increased tracer uptake related to PCa were documented as benign, metastatic or equivocal. Equivocal uptakes were finally diagnosed based on a consensus review of correlative imaging. Patient- and lesion-based analysis was performed. Patients with superscan images were excluded from lesion-based analysis.

RESULTS

At least one metastatic or equivocal uptake in skeleton was defined in 76 of 138 (55%) BS, in 33 of 102 (32.3%) SPECT/CT, and in 49 of 138 (35.5%) 68 Ga-PSMA PET/CT. 23 (16.7%) patients had also superscan findings on BS and 68 Ga-PSMA PET/CT. For patient-based analysis, sensitivity, specificity, accuracy, PPV, and NPV were calculated as 91.1%, 64.5%, 73.1%, 55.4% and 93.7% for BS; 95.5%, 82.7%, 86.9%, 72.8% and 96.2% for BS + SPECT/CT; 97.7%, 95.7%, 95.6%, 91.6% and 98.8% for 68 Ga-PSMA PET/CT. For lesion-based analysis, sensitivity, specificity, accuracy, PPV, and NPV were 53%, 63.9%, 60.1%, 42.8% and 71.8% for BS; 59.2%, 87.6%, 77.7%, 62.6% and 80% for BS + SPECT/CT; 96.4%, 98.1%, 97.5%, 96.4% and 98.1% for 68 Ga-PSMA PET/CT.

CONCLUSION

This study has shown that 68 Ga-PSMA PET/CT overcomes the limitations of BS and proves superiority in detecting bone metastases, even in patients with SPECT/CT. Our findings present important implications that 68 Ga-PSMA PET/CT can replace BS in future practice.

Prostate penile metastasis: Incidence and imaging pattern on 68 Ga-PSMA PET/CT

BACKGROUND

Prostate cancer commonly metastasises to bone and regional lymphatics and more rarely to locations such as the brain, skin and penis. Gallium-68 prostate-specific membrane antigen (⁶⁸ Ga-PSMA) positron emission tomography/computed tomography (PET/CT) has widely become the routine imaging modality for prostate cancer staging and re-staging in Australia. The aim of this study was to retrospectively review all ⁶⁸ Ga-PSMA PET/CT examinations performed to date at our institution to determine the frequency of penile metastases.

METHODS

A total of 4860 ⁶⁸ Ga-PSMA PET/CT examinations were performed between 16/07/2014 and 31/10/2019. Radiology reports for each examination were filtered to identify those with the words 'penis' or 'penile'. Once identified, relevant reports and images were individually reviewed to confirm the presence of a PSMA-avid penile lesion.

RESULTS

The incidence of penile metastasis of prostate cancer observed in this study was 0.1% with six examinations identified as having PSMA-avid penile lesions in five prostate cancer patients (age range: 71-88 years). The patients had a 1-8 year history of prostate cancer with varying severity of disease. Appearance of PSMA-avidity varied between single focal lesion, multiple focal lesions and diffuse lesion.

CONCLUSIONS

An incidence of 0.1% in our study confirms the rarity of penile metastases of prostate cancer. Although rare, identification of prostate cancer penile metastases is important for appropriate treatment management and symptom-relief.