Fabio Almeida MD, Presenter: Nothing to Disclose

Steven Eric Finkelstein MD, Abstract Co-Author: Nothing to Disclose

Mark Scholz MD, Abstract Co-Author: Nothing to Disclose

Richard Lam MD, Abstract Co-Author: Nothing to Disclose

Jeffrey Turner MD, Abstract Co-Author: Nothing to Disclose

Elisa Blackwell, Abstract Co-Author: Nothing to Disclose

A rising PSA after definitive therapy possess a significant problem, as it represents a large group of prostate cancer (PCa) patients. These patients often have the absence of sufficiently detectable disease on standard imaging studies, thereby limiting treatment options.

373 C11-Acetate (CA) PET/CT studies were reviewed in an ongoing single site FDA/IND clinical study. Male patients with histologically proven PCa and biochemical recurrence (BCR) were imaged. Imaging was performed from vertex - thighs on an integrated PET/CT scanner with imaging 3 to 7 minutes post injection. Detected lesions were defined as moderate-intense focal areas of increased metabolic activity over background in the prostate, bed, nodes and bone.

PSA ranged from 0.2 – 148 ng/mL (mean 6.3, median 2.7). The overall detection rate was 87%. At various PSA subgroups the detection rates were: 0.2-0.4 = 50%, 0.41 – 1.0 = 77%, >1.1 90%. True positive (TP) studies were defined as those with positive biopsy, confirmatory imaging or where radiotherapy (RT) was directed at the detected site with a resultant drop in PSA. 145 patients have thus far met criteria for TP analysis, with a PPV of 94%. Focal lesions were detected only in the prostate or bed in 28% (post prostatectomy [RP]: 32%, post RT: 31%, post RP-RT: 11%). In 24% of studies, only focal pelvic nodal lesions were detected (RP:32%, RT:13%, RP-RT: 41%). Lesions where detected in both the prostate/bed and pelvic nodes in 7%. Metabolic lesions were detected in both the pelvis and abdomen in 7% and isolated to abdominal nodes in 3%. Bone lesions were found in 28% of the studies (71% in bone only and 29% with soft tissue lesions). In 3%, lesions where detected in the other areas such as the lungs, mediastinal nodes or in supraclavicular nodes (particularly on the left).

In patients with BCR of PCa, CA PET/CT imaging demonstrates a high detection rate and PPV for the site(s) of recurrence/metastasis. Particularly evident is the high detection of locally recurrent and intra-pelvic nodal disease (59%), which may be amenable to focal therapy with a curative intent. CA PET/CT was also able to better identify those with distant metastases, whom would most benefit from systemic therapy.

Conventional imaging is of limited value in BCR PCa and CA PET imaging appears to help differentiate those with local-regional disease from distant metastasis.

Almeida, F, Finkelstein, S, Scholz, M, Lam, R, Turner, J, Blackwell, E, Detection of Intra-pelvic vs Extra-pelvic Lesions with Carbon-11 Acetate Positron Emission Tomography/Computed Tomography Imaging in the Evaluation of Recurrent Prostate Cancer: Interim Results from the AMIC-AC-001 Clinical Study.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14009384.html