A Crystal Ball for Chemotherapy? New Hope for Personalized Cancer Treatment

Cancer doctors may be one step closer to personalizing treatment for patients based on each individual's biochemistry. Scientists at UCLA have developed a non-invasive procedure that may help doctors evaluate how tumors respond to particular drugs. This would go a long way toward helping doctors choose and evolve effective and durable chemotherapy drug regimens based on each patient's unique response over time.

This potential "crystal ball" capability is the result of a procedure that uses probes and PET scans to image how a tumor responds to a particular drug. "For the first time," said Dr. Caius Radu, one of the UCLA researchers, "we can watch a chemotherapy drug working inside the living body in real time." The procedure has been tested on mice. Next researchers will test whether the procedure will work for a range of chemotherapeutic drugs.

To watch real-time tumor responses to a drug, Dr. Radu and his team created a small probe based on gemcitabine, a chemotherapy drug. They then tagged the probe with positron-emitting particles. Those particles glow when subjected to a PET scan. PET, or positron emission tomography, is a scan often used to determine if tumors have spread or come back in cancer patients.

In a recent study, scientists injected the probe into mice that had leukemia and lymphoma, two types of cancer. Using the PET scanner, scientists could watch how the tumors responded to the probe. One tumor was known to be sensitive to gemcitabine. The other tumor was known to be resistant to that drug. When researchers watched the probe moving through the living body of the mouse, only the tumor known to be sensitive to gemcitabine absorbed the probe.

In effect, the probe offered doctors a preview of how the tumor would respond to the particular drug. According to Science Daily, Rachel Laing, first author of the study, stated that the team believed "the tumor cells that absorb the probe will also take up the drug." If the probe isn't absorbed, it may signal doctors that a different medicine should be tried.

Probes also could be helpful in determining if a tumor that had been responding to chemotherapy had become resistant to a particular drug. Researchers at the Memorial Sloan-Kettering Cancer Center in New York note that "acquired resistance to chemotherapy is a major obstacle to successful cancer treatment."

The next step for the UCLA researchers is to try the same probe and PET scan procedure using a variety of chemotherapy drugs. If the probes are absorbed by some tumors and not others in a clinically significant way, the procedure will be tested on healthy human volunteers. If the procedure is safe and effective in healthy volunteers, it will be tested in a larger study in cancer patients.

While cancer doctors still don't have a "crystal ball" to see into a patient's unique response to various drugs, the UCLA probe and PET scan procedure represents one step closer to the development of personalized cancer treatment. This non-invasive procedure, that does not have significant side effects, could truly revolutionize choosing and evolving individualized chemotherapy regimens.

Sources:

"Scientists Develop 'Crystal Ball' For Personalized Cancer Treatment," Science Daily.

"Resistance To Chemotherapy: How Tumors Acquire Resistance To Kinase Inhibitors," Science Daily.