Integrated images pinpoint site of recurrent prostate cancer

May 21, 2007

Superimposing PET and CT images acquired using [11C] choline in patients with rising PSA following therapy for prostate cancer can identify and anatomically locate cancer recurrence, according to a study from Germany.

Superimposing PET and CT images acquired using [11C] choline in patients with rising PSA following therapy for prostate cancer can identify and anatomically locate cancer recurrence, according to a study from Germany.

The images may provide valuable information to physicians and their patients who must choose between targeted therapies, such as radiation or systemic hormonal therapies.

"That can be a difficult decision. We wanted to see if we could help clarify that decision," Ludwig Rinnab, MD, of the University of Ulm, told Urology Times at the AUA annual meeting yesterday.

Dr. Rinnab and colleagues identified 50 patients who had undergone treatment for prostate cancer. Forty were treated with radical prostatectomy, seven with external beam radiation, and three with brachytherapy. When rising PSA was evident, all patients underwent a PET scan and CT with a choline tracer.

"It is established that patients with prostate cancer show increased uptake of choline in cancerous cells and that this uptake can be imaged with computed tomography," Dr. Rinnab explained.

Mean PSA levels in choline-positive patients was 2.42 ng/mL compared to 0.90 ng/mL in choline-negative patients. Cytology in these patients showed that at a PSA of 2.5 ng/mL, the sensitivity of the procedure was 91% with a specificity of 50%. The sensitivity correlated with PSA levels and rose as PSA rose.

Dr. Rinnab reiterated that the purpose of the study was not to identify recurrence, but to characterize it and to use the information for clinical and prognostic decisions. He said studies will continue in order to elucidate in greater detail the value and application of this approach.