Systematic Review & Meta-Analysis of Positron Emission Tomography/Computed Tomography and Bone Scan in the Diagnosis of Prostate Lesions

Jiafu Wang; Yue Han; Lin Lin; Linhan Zhang; Jin Li; Huiqi Gao; Peng Fu

Disclosures

Transl Androl Urol. 2021;10(11):4231-4240. 

In This Article

Discussion

The presence or absence of bone metastases plays an important role in the staging, treatment and prognosis of prostate cancer.[20] BSs are performed to look for the presence of bone metastases and determine their extent; however, FN results are often found on BSs in the early stages of bone metastasis from malignant tumors.[21] The sensitivity and specificity of prostate membrane antigen targeted radionuclide molecular imaging in detecting lymph node metastasis are over 80%, which can identify the metastatic lymph nodes with the maximum diameter of 2.4 mm to the greatest extent. Therefore, taking PSMA as the target and 68Ga as the tracking agent can make PET/CT examination more accurate and make up for the shortcomings of traditional imaging diagnosis technology. Although there have been many studies on the use of 68Ga-PSMA PET/CT and BS imaging to diagnose bone metastases in recent years, their findings are inconsistent. In this study, meta-analysis was therefore used to compare the relevant literature on the diagnosis of bone metastases by 68Ga-PSMA PET/CT and BS.

FNs can present on BSs due to a range of factors including bone metabolism, bone blood flow, and sympathetic nerve status. When the tumor is in the stage of rapid growth and gradually becomes highly destructive, the bone tissue around the tumor cannot meet the bone activity. In response, the humoral factors produced by tumors will inhibit bone activity, thus interfering with the uptake of bone imaging agents and finally affecting the image quality.[22]

PET has gradually shown its advantages in tumor diagnosis and is now widely used in clinical settings. It can not only accurately detect bone metastases in primary lesions, but also clarify the location, size, and nature of lesions in combination with CT. 68Ga-PSMA PET/CT can detect abnormal bone marrow involvement that has not been detected by CT, making up for the low spatial resolution of PET alone. 68Ga-PSMA PET/CT has higher sensitivity and specificity than either PET or CT alone in differentiating benign and malignant bone lesions.

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. This indicates that 68Ga-PSMA PET/CT has lower sensitivity and higher specificity than BS. In 2017, Fitzpatrick et al. reported that the sensitivity of 68Ga-PSMA PET/CT in the diagnosis of bone metastases and bone destruction was consistent with that of BS.[23]

The results of meta-analysis based on 68Ga-PSMA PET/CT of surgical and histopathological examination showed that the area under SROC curve was 0.826 with SE (AUC) =0.0425. The meta-analysis of BS showed that the area under the SROC curve was 0.714 with SE (AUC) =0.0034. These data indicate that 68Ga-PSMA PET/CT has a significant advantage over BS in the diagnosis of bone metastases.

In this study, from the 3 randomized controlled trials only 2 (66.67%) randomized controlled trials described the correct randomized allocation method, and only 1 (33.33%) described the hidden allocation scheme in detail. The fixed effects model analysis of 68Ga-PSMA PET/CT and BS for the diagnosis of bone metastases showed high reliability. Forest plots show that the circles corresponding to articles included in the study are basically concentrated near the centerline, and that the distribution of circles around the centerline is basically symmetrical. This suggests that this study is of high accuracy, that there is no publication bias, and that the final conclusion is relatively credible.

The results of systematic evaluation of this study show that 68Ga-PSMA PET/CT is superior to BS, which has better diagnostic value and more stable result scanning. Because 68Ga-PSMA PET/CT has some technical shortcomings in bone diagnosis, it cannot fully show the metastasis of prostate cancer. If necessary, it is necessary to integrate PET, BS, CT, magnetic resonance imaging, prostate specific antigen, clinical and imaging follow-up. There are some limitations in this study, such as the lack of literature, which reduces the demonstration intensity of meta-analysis. Because the quality and type of each study are inconsistent, it may affect the heterogeneity of this study. Therefore, this research still needs multi-center, large sample and prospective research to strengthen demonstration intensity.

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