Innovative PET Imaging With Cu 64 Anti-CEA in Advanced Rectal Cancer

Jeffrey Wong, MD, a professor of radiation oncology at City of Hope Medical Center, discusses findings on the use of Cu 64 anti-CEA M5A as a PET imaging agent for advanced rectal cancer presented at the 2024 American Society for Radiation Oncology (ASTRO) Annual Meeting.

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0:09 | The study was designed first for patients with locally advanced rectal cancer, most of whom did not have any known sites of metastatic disease. This with the patients were scanned prior to therapy. Therapy is, for most patients with local locally advanced rectal cancer, chemotherapy, radiation therapy, and then surgery. This study was designed to do a radiolabeled or Cu 64 anti-CEA PET scan prior to radiation therapy and chemotherapy and after radiation therapy, but prior to surgery. The objectives were to determine how this agent could identify disease before therapy, and could it also determine tumor response after therapy?

1:20 | The first scan wanted to determine whether it could identify disease. This is a pilot study, but in the number of patients we studied, all of them showed targeting of the antibody to known sites of disease patients. There were also patients where there was disease detected outside of the pelvic region. That could impact radiation field coverage, or even impact on whether a patient is appropriate for radiation therapy. That is another objective, and that was another finding.

2:05 | The third finding was that we found that after radiation therapy is done, but prior to surgery, there were patients that had a positive PET scan before therapy, but then a negative PET scan after therapy, and they went on to surgery or biopsy, and that confirmed that there was absence of a tumor when the PET scan became negative. Although more work needs to be done, the potential is that this scan, especially performed prior to surgery, might help select patients who are appropriate to just continue to watch and avoid the surgery. Again, it is a bit early to reach that conclusion, but this trial was to see if there is any potential for this particular agent to do that.