Imaging technique finds differences between radiation-sensitive and resistant tumors

Researchers have started pilot clinical studies in head and neck cancer patients to determine if Raman spectroscopy, a noninvasive imaging technique, can effectively spare some patients of the toxic side effects of ineffective radiation therapy.

Researchers at the University of Arkansas, Johns Hopkins University and the University of Arkansas for Medical Sciences (UAMS) used the imaging technique and discovered differences between treatment-sensitive and treatment-resistant tumors in mice after radiation. Their findings, published in Cancer Research, a journal of of the American Association for Cancer Research, revealed statistically significant differences in lipid and collagen content that could potentially identify treatment-resistant tumors early in the therapeutic regimen.

“Identifying patients with radiation-resistant tumors prior to commencing treatment or immediately after it has begun would significantly improve response rates and help these patients avoid the toxic side effects of ineffective radiation therapy,” said Narasimhan Rajaram, assistant professor of biomedical engineering at the University of Arkansas. “Our findings provide a rationale for translating these studies to patients with this as the ultimate goal.”

Rajaram and Ishan Barman, assistant professor of mechanical engineering at Johns Hopkins University, used Raman spectroscopy, an optical fiber-based, noninvasive and highly specific imaging technique to map biomolecular changes in radiation-resistant and radiation-sensitive human lung tumors and two different types of head and neck tumors. Their research team found that radiation-sensitive tumors had greater changes in the expression of lipids and collagen. These changes were consistent across all tumors.

The human clinical trials are being conducted in partnership with UAMS.

These findings follow a similar study published last year, in which Rajaram and a large interdisciplinary team of researchers at the University of Arkansas and UAMS used auto-fluoresence imaging to identify differences between the metabolic response of radiation-resistant and radiation-sensitive lung cancer cells after exposure to radiation and YC-1, a common chemotherapy drug.

Radiation is used, along with chemotherapy, to treat the majority of patients diagnosed with lung, head or neck cancers. While these treatments can last up to seven weeks, there are no accepted methods to determine treatment response before or during the early stages of therapy, which means some patients undergo a full treatment regimen only to be identified later as non-responders.

The radiation-resistant and radiation-sensitive lung cancer cells used in this study were developed by Ruud Dings, assistant professor of radiation oncology, and Robert Griffin, professor of radiation oncology at UAMS. Histological evaluations of these tumors by Dr. Matt Quick, associate professor of pathology at UAMS, were consistent with the Raman spectroscopic results.

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Sina Dadgar and Paola Monterroso Diaz, graduate students in biomedical engineering, were lead authors on the study, along with Santosh Paidi, a graduate student at Johns Hopkins University.

Funding for this study was provided by several sources, including the National Institute of Biomedical Imaging and Bioengineering, the National Institute of General Medical Sciences, the National Cancer Institute and the Arkansas Biosciences Institute.