SNMMI 2017: PET/CT, Clinical Management, and Disease Detection in Prostate Cancer

Key Points

  • The change in clinical management was especially remarkable in patients showing signs of recurrent disease—61% of treatment plans overall, including 69% for patients who had received radiation therapy and 64% of patients who had undergone surgery.
  • Conventional radiographic imaging did not detect disease in nearby lymph nodes in 39% of patients, in the prostate bed in 27% of patients, and in regions where the cancer had metastasized in 16% of patients. 
  • Primary screening of intermediate and high-risk prostate cancer led to a change in clinical management in 23% of cases.

An estimated one in seven American men will be affected by prostate cancer in their lifetime. Prostate-specific molecular imaging can help to clinically manage the disease much more efficiently, especially if the cancer returns, according to research revealed at the 2017 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) (Abstract 706).

Detecting Cancer Not Seen by Conventional Imaging

This is the first prospective study to include far-reaching data from four Australian medical centers and several hundred patients examined over the course of 18 months. For this study, prostate cancer patients underwent a combination of positron-emission tomography and computed tomography (PET/CT). This research shows that prostate-specific molecular imaging led to the detection of cancer that had not been caught by more conventional imaging. Prostate-specific PET/CT subsequently changed the course of treatment plans for 51% of patients.

“Prostate-specific PET/CT is a game-changer in the evaluation of patients with prostate cancer and has been consistently shown to represent a substantial improvement over conventional imaging for the staging of disease,” said Paul J. Roach, MBBS, Head of the Department of Nuclear Medicine at Royal North Shore Hospital in Sydney, Australia.

Imaging Details

Nuclear medicine specialists performed PET/CT in concert with gallium-68 (Ga-68) and prostate-specific membrane antigen (PSMA). Once administered, the agent zeros in on areas where the PSMA protein is being overexpressed on cell surfaces—including cancer that has metastasized from the prostate to other organs. The radioactive markers distributed across these areas of PSMA overexpression emit a signal that is picked up by the PET scanner and used to create a highly accurate map of disease.

Major Findings

Referring physicians completed intended treatment surveys prior to PET/CT imaging and once again after the results of imaging were in for a total of 431 patients in this study conducted between January 2015 and June 2016.

The change in clinical management was especially remarkable in patients showing signs of recurrent disease—61% of treatment plans overall, including 69% for patients who had received radiation therapy and 64% of patients who had undergone surgery. Conventional radiographic imaging did not detect disease in nearby lymph nodes in 39% of patients, in the prostate bed in 27% of patients, and in regions where the cancer had metastasized in 16% of patients. Primary screening of intermediate-risk and high-risk prostate cancer led to a change in clinical management in 23% of cases.

This and further research could provide the data needed for governments to fund and insurers to approve this new advanced molecular imaging procedure.

“This is likely to become the primary imaging test for many patients with prostate cancer and will replace conventional imaging in many cases,” noted Dr. Roach. “Given the prevalence of prostate cancer, this could lead to a significant increase in referrals to nuclear medicine and PET centers for Ga-68 PSMA PET/CT imaging worldwide.”

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


Advertisement

Advertisement



Advertisement

click me