Bone scan is of doubtful value as a first staging test in the primary presentation of prostate cancer

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.

Correlation of cancer antigen 15-3 (CA15-3) serum level and bony metastases in breast cancer patients

Background: Cancer antigen 15-3 (CA15-3) is a common tumor marker and the serum level of this tumor marker is evaluated during the treatment period (periodically) in breast cancer patients. Assuming that the elevated serum levels of this tumor marker can be a potential risk, this study was conducted to determine the association between CA15-3 and bone metastasis and CA15-3 and metastasis spreading rate in breast cancer patients. Methods: In this study, 70 women with the mean of age 51.69 (10.77) years who suffered from breast cancer were studied by performing both bone scintigraphy and measuring CA15-3. Independent sample t test, Fisher's exact test, Spearman rho correlation, and logistic regression were used for inferential section. To determine the new cross section, Roc curve and coordinates of the curve were applied. Also, significance level was set at p<0.05. Data were analyzed by SPSS 16 software. Results: There was no difference among patients in age (p=0.123). Assuming the CA15-3 (≥ 30 U/mL) as a potential risk, there was no association between CA15-3 and bone metastases (p=0.167). Based on Spearman's rank correlation coefficient, there was no significant correlation between CA15-3 and metastasis spreading rate (r=-0.07, p=0.851). Based on ROC curve and Youden's J statistic index, the new cutoff was pointed at CA15-3 ≥21.76 Unit/mL, which correlated with bone metastases (p<0.001). Conclusion: This study found a decreased cutoff point at CA15-3 (≥21.76) against 30 (routine value). Based on CA15-3 (≥21.76), there was a correlation between bone metastases and CA15-3, indicating that patients with CA15-3 (≥21.76) were most likely to experience bone metastases.

Gallium-68 prostate-specific membrane antigen positron emission tomography/computed tomography compared with diagnostic computed tomography in relapsed prostate cancer

The aim of this study was to evaluate if prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) has a higher detection rate compared to standard contrast CT imaging for patients with a rising prostate-specific antigen (PSA) following definitive treatment (i.e., curative radical prostatectomy, radiotherapy, and brachytherapy) for prostate cancer in a private hospital setting. A retrospective single-site clinical audit was conducted on 150 PSMA PET/CT scans done for patients with a rising PSA after definitive treatment for prostate cancer. All studies were performed using I and T Ga-68 PSMA produced on a Scintomics radiopharmaceutical unit (Munich). All scans were performed on a GE 710 PET/CT scanner. All studies were compared to standard CT and other imaging. Of the 150 patients who had a ⁶⁸Gallium (Ga)-PSMA PET/CT for a rise in their PSA levels, 102/150 (68%) of patients had PSMA-avid scans compared to the conventional imaging group which had an overall detection rate of 42% (63/150). The rates of detection were 100%, 90%, 92%, 67%, and 25% at PSA levels of >10 μg/L, 5–10 μg/L, >1.5 μg/L, 0.5–1.5 μg/L, and <0.5 μg/L, respectively. PSMA PET/CT also solely picked up 39/102 (38%) of prostate cancer relapses compared to the conventional imaging group. In our study of 150 patients with biochemical recurrence of prostate cancer, ⁶⁸Ga-PSMA PET/CT demonstrated a superior detection rate (P < 0.05) compared to conventional imaging, including patients with low PSA levels (<0.5 μg/L).