Intraindividual comparison of 99m Tc-HYNIC-PSMA-11 and 99m Tc-MDP bone scan with SPECT/CT for detecting skeletal...

Skeletal metastasis is not only associated with pain but also constitutes a prevalent cause of mortality in patients with prostate cancer (PC). Accurate evaluation of skeletal disease status is essential in the management of PC. This study examines the concordance between 99m Tc-prostate-specific membrane antigen (PSMA) and 99m Tc-Methylene Diphosphonate (MDP) scans for detecting skeletal metastases in PC patients.

This prospective study evaluated 18 participants with histopathologically confirmed PC from July 2022 to July 2024. All patients underwent 99m Tc-PSMA and 99m Tc-MDP single-photon emission computed tomography/computed tomography (SPECT/CT) within an average interval of 9.5 days. Lesions were categorized on an ordinal scale. The Wilcoxon signed-rank test was employed for statistical comparison.

The median prostate-specific antigen (PSA) at the time of the study was 85.9ng/ml. The disease was predominantly advanced, with 14 patients (74%) exhibiting stage 4b. The Gleason scores were 8-10 ( n  = 16) and 7 ( n  = 2). Total 244 skeletal lesions were detected. 99m Tc-MDP identified 233 lesions (95.5%), whereas 99m Tc-PSMA identified 176 lesions (72.1%). The disparity in lesion count across scans was not statistically significant ( Z  = 1.6, P  = 0.11). Area under the curve for receiver operating characteristic analysis of 99m Tc-PSMA for skeletal lesion detection was 0.878, signifying high diagnostic precision.

The 99m Tc-PSMA scan exhibited comparable efficacy to 99m Tc-MDP bone scintigraphy in identifying skeletal metastases in PC. The capability to identify both skeletal and supplementary soft tissue metastases, together with its potential theragnostic applications, establishes 99m Tc-PSMA scan as a viable comprehensive imaging solution, especially in resource-constrained settings with limited PSMA PET/CT access and poor patient affordability.