Prostate Specific Membrane Antigen (PSMA) PET Imaging for Prostate Cancer

Illustration of a PSMA PET/CT with abnormal tracer activity confined to the left prostate lobe, consistent with biopsy proved cancer. No evidence of PSMA-avid metastasis.

What is a PSMA PET Scan?

A PSMA PET/CT scan is an imaging test used for the diagnosis and management of prostate cancer. PSMA stands for prostate-specific membrane antigen, a protein found on the surface of prostate cancer cells. In a PSMA PET/CT scan, a radioactive molecule that specifically binds to the PSMA protein is used as a tracer. This tracer is combined with a radioactive compound or isotope. The scan detects the areas where this tracer accumulates, thus identifying prostate cancer cells in the body34. 

Statistics

Prostate cancer is the most common cancer among men, except for skin cancer. In 2023, an estimated 288,300 men in the United States will be diagnosed with prostate cancer. Worldwide, an estimated 1,414,259 people were diagnosed with prostate cancer in 2020. It is the fourth most commonly diagnosed cancer in the world.”

PSMA PET vs  Conventional Imaging

PSMA PET scans are helpful to clinicians in several ways. Firstly, they have a higher sensitivity and specificity compared to conventional imaging techniques, such as CT and bone scans, in detecting prostate cancer lesions and metastases. This makes them more accurate and reliable for staging and restaging prostate cancer4. PSMA PET scans can detect smaller lesions and micrometastatic disease that might be missed by conventional imaging, allowing for early detection and appropriate treatment decisions45. 

NCCN Commentary on PSMA PET 

The National Comprehensive Cancer Network (NCCN) guidelines recommend the use of PSMA PET/CT scans for initial staging workup for clinically localized prostate cancer of unfavorable intermediate, high, or very high risk, and for restaging after biochemical recurrence5 

The NCCN guidelines recognize the increased sensitivity and specificity of PSMA PET scans compared to conventional imaging in detecting micrometastatic disease and detecting local recurrence5. These scans have shown high accuracy in detecting prostate cancer lesions across different stages of the disease35 

The NCCN guidelines recommend the use of PSMA PET/CT scans for various stages of prostate cancer due to its superior performance compared to conventional imaging modalities5. 

Coverage 

General coverage involves history of prostate cancer with a rising PSA following treatment for malignant neoplasm of prostate. 

Sources: 

  1. Global Cancer Observatory: Prostate Cancer Fact Sheet. source  
  1. American Cancer Society: Key Statistics for Prostate Cancer. source  
  1. PSMA PET and PET/CT in Prostate Cancer – Clinical Update. source 2 
  1. The Continuum of Metastatic Prostate Cancer: Interpreting PSMA PET. source 2 3 
  1. NCCN Guidelines Prostate Cancer v.2.2021. source 2 3 4 5