Scientists at University of California Los Angeles have developed a new tool that can predict how a chemotherapy drug will work on individual tumour.
The breakthrough achievement could one day evaluate a tumour's response to a drug before prescribing therapy.
The non-invasive approach could enable physicians to quickly pinpoint the most effective treatment and personalize it to the patient's unique biochemistry.
Chemotherapy can be worse than cancer for many patients, for they can respond to one drug but not another or the tumour may mutate and stop responding to the drug. This leads to months of wasted time, ineffective treatment and toxic side effects.
"For the first time, we can watch a chemotherapy drug working inside the living body in real time. We plan to test this method in healthy volunteers within the year to determine whether we can replicate our current results in humans," explained Dr. Caius Radu, assistant professor of molecular and medical pharmacology at the David Geffen School of Medicine at UCLA.
Previously, the researchers created a small probe by slightly altering the molecular structure of gemcitabine, one of the most commonly used chemotherapy drugs, and labelled it with a special tag that enabled them to watch its movement throughout the body during imaging.
In the study, researchers injected the probe into mice that had developed leukemia and lymphoma tumors.
After an hour, they imaged the animals' bodies with positron emission tomography (PET), a non-invasive scan often used on cancer patients to identify whether a tumor has spread from its original site or returned after remission.
"The PET scanner operates like a molecular camera, enabling us to watch biological processes in living animals and people. Because we tag the probe with positron-emitting particles, the cells that absorb it glow brighter under the PET scan," said Radu.
He added: "The PET scan offers a preview for how the tumor will react to a specific therapy," added first author Rachel Laing, a UCLA graduate researcher in molecular and medical pharmacology. "We believe that the tumor cells that absorb the probe will also take up the drug. If the cells do not absorb the probe, it suggests that the tumor might respond better to another medication."
Now scientists are planning to expand the scope of their research by examining whether the probe can predict cellular response to several other widely used chemotherapy drugs.
They are aiming to determine if the probe can provide a diagnostic test of clinical value.
"The beauty of this approach is that it is completely non-invasive and without side effects. If we are successful in transporting this test to a clinical setting, patients will be able to go home immediately and resume their daily activities," said Radu.
If testing in healthy subjects proves safe and effective, researchers will begin recruiting volunteers for a larger clinical study of the probe in cancer patients.
The findings are published in the advance online edition of Proceedings of the National Academy of Sciences.