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New approach: Tumor response in cancer patients
Method measures tumors' oxygenation levels
It can be frustrating, and even heart-breaking, to find out that a lengthy course of treatment was not effective. This statement is particularly relevant for fast-growing diseases such as cervical cancer. For that reason, researchers at Ohio State University (OSU) in Columbus are excited about a new approach they have developed that can predict the outcome of radiotherapy and chemotherapy early on in cervical cancer patients.
The approach, which involves the use of serial blood tests and magnetic resonance imaging (MRI) to measure the oxygenation of tumors, was developed by Nina Mayr, MD, the principal investigator on the study, and a professor of radiation medicine at OSU's James Cancer Hospital and Solove Institute in Columbus, and her husband, William T.C. Yuh, MD, MSEE, a professor of radiology at OSU. "I was prompted to do this by seeing how hopeless and dismal the outcome was in those patients who had tumor recurrence after they completed cancer therapy," says Mayr. "I was hoping to find a means to improve the prediction of outcomes so that we may change therapy strategy at a time point when it is more likely to be effective."
In findings presented at the recent annual meeting of the American Association of Physicists in Medicine (AAPM), investigators reported on their observations using the new technique in 88 cervical cancer patients who underwent radiotherapy and chemotherapy. Weekly blood tests of the participants began prior to treatment, and MRI scans were conducted before radiation treatment, during radiation at 2-3 weeks and 4-5 weeks, and at 1-2 months following treatment. In addition, cancer recurrence rates were tracked for up to nine years. Jian Wang, PhD, a lead investigator on the study and director of the radiation response modeling program at the Solove Research Institute, says, "We found that hemoglobin levels and tumor MRI perfusion measured at two weeks into treatment is optimal for tumor oxygenation evaluation and is, therefore, the best predictor of treatment outcome."
Next target: lung cancer
By determining the amount of oxygen in a cell, investigators gain critical insight about the cell's ability to repair radiation damage, says Wang, noting that when the oxygen level is low, tumor recurrence is more likely.
"If at an early stage of treatment we can identify patients with cervical cancer at great risk of local tumor recurrence, we have options and opportunities to adopt more aggressive therapy intervention such as surgical resection, dose escalation, high-dose-rate brachytherapy, or chemo/radiation therapy," Wang says.
Wang indicates that additional patients are being recruited to participate in the study and that investigators hope to further improve the accuracy of the technique. In addition, Mayr reports that John Grecula, MD, a radiation oncologist at James Cancer Hospital in Columbus, OH, and an associate professor at OSU, is engaged in a study funded by the National Institutes of Health to test the efficacy of the approach as a predictor of tumor response in lung cancer. "To bring this widely into patient care, it will be necessary to change peoples' minds on the use of tumor imaging and how it can be integrated into therapy," says Mayr. "We are currently working on bringing this technique into clinical practice in academic as well as community centers."