Researchers say that a non-invasive method can enable cancer specialists to determine after a single cycle of chemotherapy whether the treatment is killing the cancer or not.
The researchers at UCLA's Jonsson Comprehensive Cancer Center have revealed that they used a combination Positron Emission Tomography (PET) and computed tomography (CT) scanner to monitor 50 patients undergoing treatment for high-grade soft tissue sarcomas.
The patients were receiving neoadjuvant chemotherapy treatments to shrink their tumors prior to surgery, say the researchers.
The study showed that response could be determined about a week after the first dose of chemotherapy drugs.
The result attains significance because patients receiving chemotherapy are generally scanned at about three months into the treatment to determine their progress.
"The question was, how early could we pick up a response? We wanted to see if we could determine response after a single administration of chemotherapy. There's no point in giving a patient a treatment that isn't working. These treatments make patients very sick and have long-term serious side effects," said Dr. Fritz Eilber, an assistant professor of surgical oncology, director of the Sarcoma Program at UCLA's Jonsson Cancer Center and senior author of the study.
During the study, Eilber's team monitored the tumor's metabolic function, or how much sugar was being consumed by the cancer cells.
Cancer cells use much more sugar than do normal cells because they grow out of control, and thus they light up under PET scanning using a glucose uptake probe called FDG.
In order to identify an effective response to treatment, the researchers needed to see a 35 percent decrease in the tumor's metabolic activity.
Eilber says that within a week of their initial treatment, his team could determine that 28 of the 50 patients in the study did not respond.
This allows the treatment course to be discontinued or changed to another more effective treatment, getting the patient to surgery more quickly, said the researcher.
"The significance of this study was that it identified people, more than half of those in the study, who were not going to benefit from the treatment early in the course of their therapy," Eilber said.
"This information significantly helps guide patient care. Although this study was performed in patients scheduled for surgery, I think these findings will have an even greater impact on patients with inoperable tumors or metastatic disease as you get a much quicker evaluation of treatment effectiveness and can make decisions that will hugely impact quality of life," he added.
Eilber said he was surprised how soon response to therapy could be determined.
"We had an idea that patients either respond or do not respond to treatment, but we weren't sure how early you could see that. I really was not sure we would be able to see effectiveness this early," he said.
Eilber, whose team will continue following the patients, believes that the new approach may one day help personalize treatment for each patient and become the standard of care.
A research article on the study appears in the journal Clinical Cancer Research.