Avaliação diagnóstica de neoplasia de próstata : 68Ga-PSMA PET e ressonância magnética multiparamétrica

Abstract

Background: Prostate malignancy is the third most common cancer in the world and the second most frequent in male patients. In Brazil, it represents the second most common cancer among men. The identification of local recurrence and metastatic disease of the prostate tumor remains a challenge for the attending physician and for conventional imaging methods in the evaluation of these patients. Positron emission tomography associated with computed tomography (PET / CT) with the use of gallium radioisotope marked with prostate specific membrane antigen (68Ga-PSMA) and multiparametric magnetic resonance imaging (mpMR) of the pelvis has shown rapid acceptance in staging of patients with biochemical recurrence. Objective: To demonstrate the increase in the identification of lesions related to prostate cancer in patients with biochemical recurrence when using 68GaPSMA-PET/CT associated with mpMR compared to 68GaPSMA-PET/CT alone. Methods: Prospective analysis of patients in investigation of biochemical recurrence due to prostate cancer at InsCer, with 68GaPSMA-PET / CT and mpMR of the pelvis, between 08/2018 and 08/2019, performing both methods less than 5 days apart. The scans were analyzed by two different groups of specialist physician, one of which analyzed both imaging methods and the other analyzed only PET/CT images. Positive findings for recurrence of prostate cancer were classified according to their location, with recurrence at the prostate, lymph node or metastasis sites. Results: 95 out of 123 evaluated patients were included, 57 of whom were identified with lesions in the prostate bed in the combined assessment (68GaPSMA-PET/CT + mpMR) and 33 in 68GaPSMA-PET / CT alone. 44 pathological lymph nodes were observed in the 68GaPSMA-PET/CT + mpMR analysis and 29 in the isolated PET/CT, this difference being mainly due to the individualization of small lymph nodes in the pelvic region in mpMR. There was no significant difference in the number of individualized bone lesions between the groups. Conclusion: The combined analysis of 68Ga-PSMA PET/CT with mpMR of the pelvis allowed to identify a greater number of lesions in the prostate bed compared to PET/CT alone. Both techniques have complementary information, as well as different limitations.