When surgeons remove tumors, they often leave behind cancer cells that can grow and spread. To help round up such stragglers, Neoprobe Corp., a biomedical company in Dublin, Ohio, is testing a technique called radioimmunoguided surgery (RIGS) on patients with colorectal, ovarian, breast, and prostate tumors.
The brainchild of two scientists at Ohio State University, RIGS combines a cancer-specific antibody with I-125, a low-energy radioactive isotope of iodine. The compound sticks to cancer cells and alerts surgeons to their presence when the operating site is scanned by a gamma-ray probe. Neoprobe says the new treatment has translated into longer survival times in the 1,500 patients tested.
Neoprobe is using the same radioactive antibodies in patients with metastatic colorectal or pancreatic cancer to harvest CD4+ lymphocytes, helper cells that rally the body's immune system to fight invaders. In such cases, surgeons remove lymph nodes that have been infiltrated by cancer cells. Then the lymphocytes are isolated, grown in great numbers, and injected back into the patient within 10 days. Neoprobe's gamma-ray probe has been approved by the Food & Drug Administration. Next year, the company hopes to seek approval for the marker compound for use in fighting colorectal cancer.