Abstract and Introduction
Abstract
Background: To date, the results of studies into the effectiveness of positron emission tomography (PET) combined with computed tomography (CT) and bone scan (BS) in the diagnosis of malignant prostate lesions have been inconsistent, and the advantages and disadvantages of the two methods cannot be accurately judged.
Methods: Articles were retrieved from the China National Knowledge Infrastructure (CNKI) database, Wan Fang Medical Network, PubMed, Excerpta Medica data BASE (EMBASE), Medline, and Cochrane database. The keywords used in the search were: 68Ga-prostate specific membrane antibody (68Ga-PSMA), PET/CT, prostate lesions, prostate adenocarcinoma, bone metastasis, and BS.
Results: Ultimately, 3 publications were selected for inclusion in the meta-analysis. A total of 215 patients were considered in the 3 articles that met the inclusion criteria. All of the included articles were small sample studies, with sample sizes ranging from 28 to 113 cases. In this study, from the 3 randomized controlled trials, only 2 (66.67%) randomized controls described the correct randomized allocation method, and only 1 (33.33%) described the hidden allocation scheme in detail. The highest sensitivity for 68Ga-PSMA PET/CT was 0.96, with 95% CI: 0.87, 1.00, and the highest specificity was 1.00, with 95% CI: 0.96, 1.00. The highest sensitivity and specificity of BS were 0.92 with 95% CI: 0.81, 0.98 and 0.96 with 95% CI: 0.78, 1.00, respectively. The results of meta-analysis of 68Ga-PSMA PET/CT diagnosis with confirmation by surgical and histopathological examination showed that the area under the summary receiver operating characteristics (SROC) curve (AUC) =0.826 and standard error (SE) (AUC) =0.0425. The results of meta-analysis of BS diagnosis with confirmation by surgical and histopathological examination showed that the area under the SROC curve (AUC) =0.714 and SE (AUC) =0.0034.
Discussion: The meta-analysis showed that 68Ga-PSMA PET/CT has clear advantages over BS in the diagnosis of bone metastases of malignant prostate tumors, and could improve the diagnostic accuracy of bone metastases.
Introduction
There are five main pathological types of prostate epithelial malignancies: ductal adenocarcinoma, urothelial carcinoma, squamous cell carcinoma, adenosquamous carcinoma, and adenocarcinoma, among which adenocarcinoma accounts for more than 94%.[1] Adenocarcinoma is initially concentrated in the periphery of the prostate, and then develops in the central zone. Most adenocarcinomas are multifocal. According to research statistics, there were 1.2 million new cases of adenocarcinoma and 300,000 deaths worldwide in 2018. The incidence and mortality of adenocarcinoma ranked third and sixth, respectively, among male malignant tumors, and its incidence is on the rise.[2,3] The primary screening of prostate cancer is mainly through detection of prostate specific antigen and anal finger diagnosis. If a tumor is observed in the prostate of the patient through imaging, the anal examination reveals the mass in the prostate tissue, which indicates the occurrence of prostate cancer. Secondly, the value of prostate specific antigen can be used as a diagnostic screening standard. The final diagnosis of prostate cancer requires biopsy. If the pathological tissue obtained by biopsy is diagnosed as prostate cancer, the prostate cancer will be confirmed. Adenocarcinoma typically has no symptoms in the early stage. As the disease progresses, the symptoms of metastasis and compression gradually appear. Examination in the early stage of the disease is therefore very important, and the detection rate and diagnosis coincidence rate of adenocarcinoma can be significantly improved by using effective scientific diagnostic methods.
Currently, computed tomography (CT) is the most common imaging method in prostate cancer research.[4–6] CT examination is not only simple, quick and non-invasive, but also has low tolerance requirements for patients and so has been widely used in clinical settings. CT images of the prostate showing the size, shape and density of the prostate give a visual indication of whether prostate tumor has invaded the surrounding tissues.[7] CT examination has shown that the prostate volume of adenocarcinoma patients is significantly increased; however, when the tumor volume is relatively small the lesions are not easy to detect, and CT cannot accurately differentiate adenocarcinoma of different stages. The diagnostic value of CT in the early stages of adenocarcinoma is therefore not high.
Positron emission tomography (PET) combined with CT is increasingly the preferred imaging technology, with high sensitivity and specificity.[8–10] 68Ga-prostate specific membrane antibody (68Ga-PSMA) PET/CT has added functional information reflecting the metabolic changes associated with lesions to the basic morphology of lesions reflected by general CT, and in doing so has made great progress in the early diagnosis and staging of tumors. 18-fluoro-deoxyglucose (18F-FDG), by acting as a glucose analogue and increasing glycolysis metabolism in most malignant cells, has become the most commonly used radioactive tracer in 68Ga-PSMA PET/CT examinations.[11] Currently, it plays an important role in the diagnosis of many tumors.
The most common site of distant metastasis from the prostate is bone, accounting for about 85% of metastases. Routine bone scan (BS) remains the preferred imaging method for assessing bone metastases.[12,13] Whole-body BSs play an important role in staging of the tumor, the evaluation of bone pain symptoms, the judgment of patient prognosis, and the follow-up of patients. BS is a very sensitive examination method for the diagnosis of bone metastases, and is prominent in the detection of osteogenic lesions. Therefore, it has high sensitivity in the detection of bone metastases of adenocarcinoma and can detect more than 96% of bone metastases. In addition, BS can detect bone metastases 3 to 6 months earlier than x-ray and ordinary CT.[14]
The sensitivity and specificity of 68Ga-PSMA PET/CT imaging in the diagnosis of bone tumors are higher than are those of BS, and 68Ga-PSMA PET/CT can detect metastatic lesions earlier. In terms of evaluating the efficacy of identifying bone metastases, 68Ga-PSMA PET/CT imaging detects them earlier than CT or radionuclide bone scanning. Another advantage of 68Ga-PSMA PET/CT over bone scanning is that it can also show lesions in tissues outside the bone.[15] Although a large number of studies have investigated the diagnostic performance of 68Ga-PSMA PET/CT in the treatment of patients with prostate lesions, the results have been inconsistent, with sensitivity ranging from 56% to 98%.[16] Although the value of 68Ga-PSMA PET/CT imaging in the diagnosis of metastatic lesions has been confirmed in many studies, the comparison of diagnostic value of 68Ga-PSMA PET/CT and BS still warrants further exploration.
The innovation of this study is to systematically evaluate the diagnostic value of 68Ga-PSMA PET/CT and BS in bone metastasis by screening the related literatures in diagnosing prostate diseases, so as to provide high-level evidence-based evidence for clinical treatment.
We present the following article in accordance with the PRISMA reporting checklist (available at https://dx.doi.org/10.21037/tau-21-912).