PET, MRI Combination Helps Map Prostate Cancer Relapses

PET, MRI Combination Helps Map Prostate Cancer Relapses

Combining two imaging techniques has allowed researchers to study the patterns of prostate cancer recurrence following radical prostatectomy (removal of the prostate).

Titled “Contemporary Mapping Of Post-Prostatectomy Prostate Cancer Relapse With C-11 Choline PET And Multiparametric MRI,” the research report was published in the Journal of Urology by Ilya Sobol and colleagues from the Mayo Clinic, in Rochester, Minnesota.

“This study has important implications for men who have a rising prostate-specific antigen (PSA) test, also known as biochemical recurrence, after radical prostatectomy for prostate cancer,” Dr. Jeffrey Karnes, from Mayo Clinic, said in a news release. “In men with biochemical recurrence, determining where the disease has recurred is quite challenging, especially when the PSA level is low.”

According to Karnes, nearly 30 percent of men who undergo surgery to remove prostate cancer in the U.S. experience a recurrence and seek treatment. But although measuring PSA levels has significantly facilitated earlier detection of prostate cancer recurrence, “current imaging tests like conventional bone and computed tomography (CT) scans are not sensitive enough to identify sites of recurrence, especially when the PSA value is lower than 10,” he added.

To investigate which areas were most prone to suffer cancer recurrence, the researchers followed 2,466 men who underwent a positron emission tomography (PET) scan for suspected prostate cancer relapse at the clinic between January 2008 and June 2015. Of this original group, 202 had not receive hormone or radiation therapy but, through testing with both PET and multiparametric magnetic resonance imaging (MRI) examination, were found to have cancer recurrence.

The scans revealed an anatomically diverse pattern of cancer recurrence in this group: 68 (33%) exhibited local relapse, 45 (22%) showed local plus metastatic relapse, and 89 (45%) had metastatic only relapse. The team also found that 39 (19%) men in the study had recurrence limited to the pelvis.

The median PSA levels in patients who had positive imaging examination with local only, metastatic only, and local plus metastatic relapse was 2.3, 2.7 and 2.2 ng/ml, respectively. The results indicate that the combination of PET and MRI scans successfully identified sites of cancer relapse in men with average PSA levels of 2.

“This type of staging allows us to identify sites of recurrent disease that can be potentially treated either surgically or with radiation,” Kernes said.