PSMA PET Research Supports Updates to Guidelines for Prostate Cancer Treatment

Research presented at the Society of Nuclear Medicine and Molecular Imaging Annual Meeting suggests that updates may be needed to current guidelines for planning salvage radiation treatments in patients with local recurrence of prostate cancer.

Patients with prostate cancer recurrence often undergo salvage radiation therapy. The treatment is generally planned based on prostate bed contouring, according to guidelines based on expert consensus, such as those from the Radiation Therapy Oncology Group.

However, a study led by Ida Sonni, MD, of the Department of Radiology at the University of California, Los Angeles, showed that prostate-specific membrane antigen (PSMA) positron emission tomography (PET) can identify recurrences that would fall outside those guideline targets. The authors suggested that PSMA PET be added to guidelines for treatment planning.

The study analyzed patients with prostate cancer who had biochemical recurrence after radical prostatectomy. Inclusion criteria were PSMA PET/computed tomography imaging that showed recurrence in the prostate bed. Two nuclear medicine physicians and 4 radiation oncologists analyzed the patterns of recurrence and compared results.

“PSMA recurrences were fully covered by the clinical target volumes in 54% of the patients. In 34% of the patients, PSMA recurrence was only partly covered, and in 13% of patients, the PSMA recurrence was located fully outside of the clinical target volume,” Dr. Sonni said. “This study has the potential to redefine prostate bed contouring guidelines to improve the therapeutic ratio for patients receiving postoperative radiotherapy.”