Frederik Lars Giesel MD, MBA, Presenter: Nothing to Disclose

Hanna Fiedler, Abstract Co-Author: Nothing to Disclose

Clemens Kratochwil MD, Abstract Co-Author: Nothing to Disclose

Ali Afshar-Oromieh, Abstract Co-Author: Nothing to Disclose

Uwe Haberkorn MD, Abstract Co-Author: Nothing to Disclose

Florian Sterzing MD, Abstract Co-Author: Nothing to Disclose

Juergen Debus MD, PhD, Abstract Co-Author: Nothing to Disclose

Prostate cancer risk stratification is based on PSA, T-stage and Gleason score and results in improved therapeutic decision-making. The purpose of this retrospective investigation is to evaluate the impact of 68Ga-PSMA PET as a novel pre-treatment staging method prior to radiotherapy.

56 patients with prostate cancer were retrospectively analyzed with conventional CT and 68Ga-PSMA PET/CT imaging. 15 patients presented at diagnosis, while 41 patients presented with recurrence after total prostatectomy; 71% had high risk and 29% intermediate risk cancer according to the d’Amico criteria. .On conventional CT, lymph nodes were regarded as pathologically involved if their short axis diameter was ≥10mm. Lymph node involvement in 68Ga-PSMA PET was diagnosed when a node on CT demonstrated a maximum standardized uptake value (SUVmax) >2. TNM-classification was performed by two experienced readers in consensus.

26 of 56 (46.4%) patients was changed after 68Ga-PSMA PET imaging. This included 8 patients with changes at initial diagnosis and 18 patients at the time of recurrence. 13/26 patients (50%) with recurrence were changed from N0 to N1, 9 patients (34.6%) were changed from M0 to M1a, 4 patients (15.4%) were changed from M0 to M1b and 1 patient (3.8%) was changed from Tx to T2a. In 7/15 patients (46.6%) at initial diagnosis no metastases were detected in 68Ga-PSMA PET /CT. Among the 26 patients in whom 68Ga-PSMA PET upstaged their disease, all patients underwent modification of their therapy. Nodal upstaging resulted in individualized simultaneous integrated boost IMRT. With detection of distant metastases, patient management was changed from local radiotherapy to systemic therapy.

These results suggest that 68Ga-PSMA PET/CT can more accurately stage patients with prostate cancer than conventional CT leading to changes in therapy. This agent could therefore, become important for more precise treatment of patients with primary or recurrent prostate cancer.

68Ga-PSMA PET/CT can more accurately stage patients with prostate cancer than conventional imaging modalities resulting in changes of the treatment regime.

Giesel, F, Fiedler, H, Kratochwil, C, Afshar-Oromieh, A, Haberkorn, U, Sterzing, F, Debus, J, Impact of 68Ga-PSMA PET/CT in Staging of Prostate Cancer Patients prior to Radiotherapy.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14014690.html