Diagnostic value of PET/CT with gallium 68 marking with PSMA in the staging and resetting of prostate cancer

PET/CT with Gallium 68-PSMA has been positioned as a robust technique in the evaluation of prostate cancer. Our main objective was to evaluate the diagnostic utility of PET / CT with Ga 68-PSMA in patients referred for prostate cancer staging and re-staging. We included 203 patients, with average age of 67 years, average injected dose of 3,83 mCi of PSMA-Ga 68. The PSA (prostate specific antigen) value before the test was 28,44 ng/mL, in average (median 7,11 ng / mL) and the average Gleason score value was 7. The tests analyzed were performed on PET / CT equipment with the radiotracer mentioned above and using contrast medium according to institutional protocol. The statistical analysis was performed using GraphPad Prism 7,04 software, considering statistically significant 'p' value. The results were initially divided into positives (92/203) versus negatives (111/203), with percentages of 45,3% and 54,7%, respectively. Differences statistically significant were found in the PSA average (p <0.0001) and in the Gleason Score (p = 0.001). In the 92 positive cases, it was found that 47,8% had findings at local level (prostate, surgical bed, seminal); 73,9% with positive adenopathic disease and 45,7% findings signs of metastasis (bone and/or visceral). The sample was subdivided into 109 staging studies, without previous treatment of prostate cancer, with a positivity of 33,9%. A subgroup of 44 patients undergoing to surgery allowed to calculate the PSMA PET / CT performance for local involvement (sensitivity was 16%, specificity 94,7%, positive predictive value (PPV) 80%, and negative predictive value (NPV). 46%) and pelvic adenopathic per patient a sensitivity of 57,1%, specificity of 96,2%, PPV 82,8% and NPV 95,7%, in contrast to injury sensitivity of 57,1%, specificity of 96,2%, PPV 82,8% and NPV 95,7%. The analysis made to patients with reetapification examination, by increase of the prostate antigen after a first treatment, evidenced positive findings in PSMA in 58,5%, being the major determinant the PSA previous to the study. In conclusion, the data analyzed and reported show an important diagnostic value of PET / CT with Gallium 68-PSMA in the study of patients with prostatic neoplasia. The main message that we want to extrapolate with this thesis is the important use of this technique in definition and change of behavior, through the research of adenopathic or metastatic lesions approximately in half of the patients studied