Molecular Imaging in Focus: Incorporating PSMA PET into Risk Stratification for Prostate Cancer

For patients with prostate cancer (PCa), recently published research in Lancet Oncology revealed fairly striking differences between traditional clinical risk scoring models and newly developed nomogram models that incorporate PSMA PET imaging data.

In an international retrospective study involving 11,154 patients, researchers compared visual and quantitative PSMA PET nomograms to established clinical risk scoring models from the European Association of Urology (EAU) and the National Comprehensive Cancer Network (NCCN). For risk stratification in patients with biochemical recurrence of PCa, the visual and quantitative PSMA PET nomograms offered 12 and 14 percent higher AUCs than the EAU risk scoring model.

Both PSMA PET nomograms provided an 84 percent AUC for risk stratification across multiple PCa disease groups in contrast to 77 percent for the NCCN clinical risk model, according to the study.

In a recent interview with Diagnostic Imaging, Jeremie Calais, MD, PhD, a co-author of the study, said it was great to see the evidence and long-term outcome data reflecting what he sees in clinical practice.

“When I read a PET scan, I can visually quantify the intensity of uptake, visually quantify the volume, and see where the lesions are, but having this (evidence) in such a big number of patients, and putting all these together with a nomogram scoring system with weights and points, for me, this is always nice. It's like putting what I see from my brain into numbers and statistics and papers and actually reflecting outcomes. This is what is great when you are able to merge such a big data set and do nomograms,” explained Dr. Calais, the director of clinical research and theranostics programs, and an associate professor at the University of California-Los Angeles (UCLA).

(Editor’s note: For related content on prostate cancer imaging, click here.)

While noting that multiple studies have demonstrated the advantages of PSMA PET over conventional imaging for detection and treatment monitoring with PCa lesions, Dr. Calais is hopeful that this nomogram approach and recently published recommendations for incorporating PET imaging into clinical trial designs may facilitate broader adoption of PSMA PET.

“… We hope that this will help PSMA PET to be better used, and especially for the regulators, FDA and others and all the clinical trial sponsors to read out this trial that we are able to use PSMA PET scan because there is value in this information we get, and we have to move beyond CT and bone scan for tumor response assessment,” maintained Dr. Calais.

(Editor’s note: For related content, see “Can PSMA PET Reinvent Risk Stratification for Prostate Cancer?,” “Emerging Concepts in Detecting and Treating Prostate Cancer: An Interview with Daniel George, MD” and “What New Research Reveals About 18F-flotufolastat PET/CT for Detecting Biochemical Recurrence and Bone Metastasis in PCa.”)