PET/CT scans with the imaging agent choline can help detect prostate cancer earlier than conventional imaging technologies for some patients who have already had their prostates removed, according to a study in this month's Journal of Nuclear Medicine.
Prostate cancer is the second most common cause of cancer death in men over 50 years of age and the incidence of prostate cancer has “dramatically” increased in the last few years, said Paulo Castellucci of the nuclear medicine unit, hematology/oncology and laboratory medicine department at the University of Bologna in Italy and colleagues. Tumor recurrence is very common—relapse after primary therapy occurs within 10 years in 20 to 30 percent in patients who have undergone prostatectomy and within five years in 53 percent of patients after they’ve received external-beam radiotherapy.
Physicians monitor patients who have undergone prostatectomies by checking on prostate-specific antigen levels (PSA) in the blood. When those levels indicate a recurrence of cancer—a biochemical relapse—physicians need to be able “to discriminate between single or multiple lesions, local relapse, or distant metastatic disease to choose the appropriate treatment.”
According to the authors, conventional imaging techniques such as transrectal ultrasound, CT, MRI and bone scintigraphy provide limited accuracy in cases of biochemical relapse.
The study included 190 men (with a mean age of 68) who had previously undergone radical prostatectomy and had experienced a biochemical recurrence of prostate cancer. The patients were grouped according to PSA levels and studied with C-choline PET/CT.
The authors found that whole-body C-choline PET/CT imaging proved to be significantly better than conventional imaging technologies in detecting prostate cancer in patients who have experienced a biochemical relapse after prostatectomy.
"In most patients with biochemical relapse after radical prostatectomy, conventional imaging methods often return false-negative results, meaning that the imaging techniques fail to detect cancer that is present in the body," said Castellucci. "Our study found that for some patients, PET/CT with choline can improve the detection of cancer soon after PSA levels are measured. This enables physicians to tailor treatment to individual patients in the early stages of recurrence, thus increasing their chances of recovery."