The performance of 18F-PSMA PET/CT in the detection of prostate cancer: a systematic review and meta-analysis

Enhancing prostate cancer diagnosis and reducing unnecessary biopsies with [18F]DCFPyL PET/CT imaging in PI-RADS 3/4 patients

For patients presenting with prostate imaging reporting and data system (PI-RADS) 3/4 findings on magnetic resonance imaging (MRI) examinations, the standard recommendation typically involves undergoing a biopsy for pathological assessment to ascertain the nature of the lesion. This course of action, though essential for accurate diagnosis, invariably amplifies the psychological distress experienced by patients and introduces a host of potential complications associated with the biopsy procedure. However, [18F]DCFPyL PET/CT imaging emerges as a promising alternative, demonstrating considerable diagnostic efficacy in discerning benign prostate lesions from malignant ones. This study aims to explore the diagnostic value of [18F]DCFPyL PET/CT imaging for prostate cancer in patients with PI-RADS 3/4 lesions, assisting in clinical decision-making to avoid unnecessary biopsies. 30 patients diagnosed with PI-RADS 3/4 lesions through mpMRI underwent [18F]DCFPyL PET/CT imaging, with final biopsy pathology results as the "reference standard". Diagnostic performance was assessed through receiver operating characteristic (ROC) analysis, evaluating the diagnostic efficacy of molecular imaging PSMA (miPSMA) visual analysis and semi-quantitative analysis in [18F]DCFPyL PET/CT imaging. Lesions were assigned miPSMA scores according to the prostate cancer molecular imaging standardized evaluation criteria. Among the 30 patients, 13 were pathologically confirmed to have prostate cancer. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of visual analysis in [18F]DCFPyL PET/CT imaging for diagnosing PI-RADS 3/4 lesions were 61.5%, 88.2%, 80.0%, 75.0%, and 76.5%, respectively. Using SUVmax 4.17 as the optimal threshold, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for diagnosis were 92.3%, 88.2%, 85.7%, 93.8%, and 90.0%, respectively. The area under the ROC curve (AUC) for semi-quantitative analysis was 0.94, significantly higher than visual analysis at 0.80. [18F]DCFPyL PET/CT imaging accurately diagnosed benign lesions in 15 (50%) of the PI-RADS 3/4 patients. For patients with PI-RADS 4 lesions, the positive predictive value of [18F]DCFPyL PET/CT imaging reached 100%. [18F]DCFPyL PET/CT imaging provides potential preoperative prediction of lesion nature in mpMRI PI-RADS 3/4 patients, which may aid in treatment decision-making and reducing unnecessary biopsies.

Detection support of lesions in patients with prostate cancer using [Formula: see text]-PSMA 1007 PET/CT

PURPOSE

This study proposes a detection support system for primary and metastatic lesions of prostate cancer using [Formula: see text]-PSMA 1007 positron emission tomography/computed tomography (PET/CT) images with non-image information, including patient metadata and location information of an input slice image.

METHODS

A convolutional neural network with condition generators and feature-wise linear modulation (FiLM) layers was employed to allow input of not only PET/CT images but also non-image information, namely, Gleason score, flag of pre- or post-prostatectomy, and normalized z-coordinate of an input slice. We explored the insertion position of the FiLM layers to optimize the conditioning of the network using non-image information.

RESULTS

[Formula: see text]-PSMA 1007 PET/CT images were collected from 163 patients with prostate cancer and applied to the proposed system in a threefold cross-validation manner to evaluate the performance. The proposed system achieved a Dice score of 0.5732 (per case) and sensitivity of 0.8200 (per lesion), which are 3.87 and 4.16 points higher than the network without non-image information.

CONCLUSION

This study demonstrated the effectiveness of the use of non-image information, including metadata of the patient and location information of the input slice image, in the detection of prostate cancer from [Formula: see text]-PSMA 1007 PET/CT images. Improvement in the sensitivity of inactive and small lesions remains a future challenge.

Detection Rate of PSMA PET Using Different Ligands in Men with Biochemical Recurrent Prostate Cancer Following Radical Treatment: A Systematic Review and Meta-analysis of Prospective Studies

BACKGROUND

Despite the acknowledged diagnostic detection rate of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging in prostate cancer, little is known about the quality of evidence, particularly focusing on prospective studies. Most systematic reviews are based on retrospective reports.

RATIONALE AND OBJECTIVES

To conduct systematic review and meta-analysis of prospective studies reporting the diagnostic detection rate of PSMA PET (computed tomography (CT) and MR) for the detection of biochemically recurrent metastatic prostate cancer.

MATERIALS AND METHODS

We systematically searched PubMed, MEDLINE, Embase, and Scopus, from database until March 1, 2023 for randomized controlled trials and prospective studies using PSMA PET imaging in prostate cancer. The primary endpoint was to assess diagnostic detection rate of PSMA PET imaging in the detection of recurrent prostate cancer in men with biochemical relapse following radical treatment. We calculated the pooled overall diagnostic detection rate with 95% CI using a random-effects model and assessed the heterogeneity between the studies including risk of biases estimation.

RESULTS

A total of 6800 patients from 32 articles were included in this study. The overall detection rate of PSMA PET for prostate cancer was 0.67 (95% CI, 0.63, 0.71). For histologically confirmed lymph nodes, the PPV from 13 prospective studies containing 1496 patients was 0.96 (95% CI, 0.93, 0.99). We performed a subgroup analysis of PSMA PET detection rates according to categorically grouped Prostate Specific Antigen (PSA) values of 0-0.5, 0.5-1.0, 1.0-2.0, and >2.0 ng/ml and obtained detection rates of 0.44, 0.63, 0.82, and 0.94, respectively. The detection rate of 18F PSMA was better in men with a PSA between 1 ng/ml and 2 ng/ml in comparison to 68Ga PSMA (0.91 with 95% CI 0.81-0.99 vs. 0.79 with 95% CI 0.73, 0.85).

CONCLUSION

PSMA PET imaging provides a good detection rate for the metastatic recurrence of prostate cancer in men with biochemical relapse following radical treatment. The detection rate improves significantly above a serum PSA value of 1 ng/ml. The diagnostic detection rate of 18F-PSMA is best at PSA values between 1 and 2 ng/ml, in comparison to 68Ga PSMA. This conclusion is heavily biased, further research needs to focus on better methodology to minimize the risk of biases.