Role of 68Ga-PSMA PET/CT in Initial Staging of Prostate Cancer and Correlation with PSA and Gleason Score

Abstract

PC is the second most common male malignancy. Its prognosis depends on the tumor stage as well as its aggressiveness; expressed histopathologically by Gleason scores. Furthermore, optimal patient management depends on the tumor stage. Thus, accurate pre-treatment staging is the cornerstone for patient management and outcome prediction in cancer prostate. Conventional imaging modalities include CT, MRI, and bone scintigraphy were regarded as the standard, non-invasive staging tools for many years. However, they had a major disadvantage of underestimating the disease burden on the account of their low sensitivity for the detection of metastatic lymph nodes, leading to inaccurate pre-treatment staging. 68Ga PSMA PET/CT is a relatively new imaging modality combining functional and anatomical imaging with the advantage of being specific for PC cells anywhere in the body. 68Ga PSMA PET/CT has a wide spectrum of uses in prostate malignancy, some of them are comprehensively studied while others are still under investigation. The most widely accepted use currently is the accurate initial staging of cancer prostate, as it shows high sensitivity and specificity for the detection of primary and metastatic lesions. 68Ga PSMA PET/CT also has a role in detecting the exact location of the primary tumor site within the prostate, as well as the presence of extra-prostatic extension into nearby organs as SV, the presence of regional nodal metastasis, and distant metastasis whether nodal, osseous or visceral. All of which greatly affect the staging and thus, the treatment plan. Other potential uses of 68Ga PSMA PET/CT include predicting the long-term outcome through taking part in the assessment of the prognosis, with SUVmax being a promising prognostic parameter correlating significantly with other established prognostic parameters, including the Gleason score and the PSA levels.