UCLA research may lead to improved cancer survival
Chemotherapy administered to cancer patients has varying degrees of success, ranging from none to complete. Thus, any procedure that can identify how well a particular regimen is working can provide valuable information as to whether it should be continued or altered. On April 1, researchers affiliated with UCLA’s Jonsson Cancer Center published a study addressing that issue in Clinical Cancer Research, a peer-reviewed journal of the American Association of Cancer Research.
The researchers conducted their study on 39 patients with soft tissue sarcomas. A sarcoma is a cancer that arises from transformed cells of mesenchymal origin. These tumors are composed of cancerous bone, cartilage, fat, muscle, vascular, or blood tissue. Sarcomas differ from cancers arising from epithelial cells, which are termed carcinomas. The researchers found that an early Positron Emission Tomography (PET) response after the initial cycle of chemotherapy can be used to predict increased survival in patients with soft tissue sarcomas.
Previous studies by the UCLA researchers had shown that use of FDG PET/computed tomography (CT) could determine pathologic response after the first dose of chemotherapy drugs. The researchers then wanted to determine whether patients showing a significant PET response after the first round of chemotherapy were also surviving longer, noted senior author Dr. Fritz Eilber, an associate professor of surgical oncology, director of the Sarcoma Program at UCLA’s Jonsson Cancer Center. He explained, “We did find that patients who experienced an early PET response to treatment had significantly increased survival. This is vital because patients want to know if the drugs are working and what that says about their ultimate outcome.”
The study participants underwent a PET scan to measure their tumor’s metabolism, or how much glucose was being taken up by the tumor, prior to getting chemotherapy. The patients were given another PET scan after the first round of chemotherapy. Those whose tumors demonstrated a 25% or more decrease in metabolic activity – a response considered significant - were determined later to have significant increased survival rates compared to those patients who had less than a 25% decrease. Dr. Eilber explained, “It’s an important finding because we can now identify whether patients are getting the right chemotherapy very quickly. Patients don’t want to have to wait until the cancer recurs or they die to find out whether their chemotherapy worked or not.”
The researchers are now in the process of designing new molecular imaging tools that may tell them even more about a patient’s cancer beyond the conventional FDG probe. Dr. Eilber noted, “Just looking at the size of the tumor is not good enough anymore. We want to image what’s happening within the tumor in real time.”
The authors wrote: “This study suggests that PET allows survival predictions after the initial cycle of neoadjuvant chemotherapy and might therefore potentially serve as an early endpoint biomarker. Such information cannot be derived from CT scanning based on serial tumor size measurements. The ability to assess treatment response early during the course of therapy can potentially guide management decisions. Treatment could be switched from neoadjuvant chemotherapy to immediate surgery in non-responding patients, while it would be continued in responders. Such risk adapted therapy could reduce treatment associated morbidity and costs.”
UCLA's Jonsson Comprehensive Cancer Center houses more than 240 researchers and clinicians engaged in disease research, prevention, detection, control, treatment and education. One of the nation's largest comprehensive cancer centers, the Jonsson center is dedicated to promoting research and translating basic science into leading-edge clinical studies. In July 2011, the Jonsson Cancer Center was named among the top 10 cancer centers nationwide by U.S. News & World Report, a ranking it has held for 11 of the last 12 years. For more information on the Jonsson Cancer Center, visit its website at this link.