A new cancer-seeking compound that can trace a pancreatic tumor’s outline with exceptional clarity, then attack cancer cells while leaving healthy tissues alone, is undergoing tests at the Roswell Park Comprehensive Cancer Center’s Photodynamic Therapy Center.
The “see and treat” agent, I124-chlor, could present a minimally invasive alternative to surgery, radiation and chemotherapy.
Principal investigator Wen Wee Ma, MD, of Roswell Park’s Phase One and Gastrointestinal Cancer Programs, explains: “Positron emission tomography — PET — is a standard tool in the clinic for imaging tissues deep inside the body. In a conventional PET scan, we tag glucose molecule with a radioactive tracer (Fluorodeoxyglucose, FDG), and inject it into the patient.”
“Since cancer cells take up more FDG than normal cells, the PET scanner can construct a 3-D map of the cancer site by detecting the signal from the FDG. “
“Unfortunately, the map by FDG-PET is not always clear or accurate. Infection, inflammation — even body fat — can take up FDG as well, causing false positives.” This ambiguity, he says, can complicate diagnoses that necessitate further biopsies, with attendant risk of pain, infection and associated complications.
“It would be good to have a noninvasive way of detecting cancer cells only. Now, because of I124-chlor’s affinity for pancreatic cancer over normal tissues, we can use it in place of FDG to get a more accurate map of the whereabouts of cancer cells.”
“One more advantage,” Dr. Ma says. “Not only does I124-chlor home in on cancer cells; it also can deliver physical damage.” Thanks to I-chlor’s photosensitizing property, laser light of specific wavelengths applied to a tumor containing it causes cancer cells to overheat, killing them without affecting normal cells. A fiber-optic endoscope, introduced through a keyhole incision, carries laser light to the site.
The path to clinical use could be short, he suggests, because I124-chlor is based on a FDA-approved photosensitizer developed at Roswell Park, and the new technique employs widely available PET and endoscopic technology.
“Today, pancreatic cancer remains a highly fatal disease ,” he says “This compound could point us toward more accurate diagnoses and more effective treatments.”