Radiation Oncology Research News

Newswise — The following news tips are based on abstracts to be presented at the annual meeting of the American Society for Therapeutic Radiology and Oncology (ASTRO), October 19 " 23, 2003 in Salt Lake City, Utah. The information described below is embargoed until the date and time of presentation. GENE SILENCER MAY IMPROVE CHEMO AND RADIATION Like bacteria that resist common antibiotics, cancer cells can survive chemotherapy and radiation. Radiation oncologists at the Johns Hopkins Kimmel Cancer Center report they have found a gene "silencer" that blocks a cancer cell's ability to repair itself after drugs and radiation cause damage. Engineered pieces of protein-encoding RNA (ribonucleic acid), the mirror image of genes' building blocks, were used to target repair proteins in cancer cells effectively shutting the RNA down. Unable to make the necessary repair proteins, cancer cells then become susceptible to the therapy. "By dismantling the cancer cell's machinery to produce these repair proteins, we destroy its ability to withstand toxic chemotherapy and radiation treatments," says Theodore DeWeese, M.D., director of the Department of Radiation Oncology at the Johns Hopkins Kimmel Cancer Center. The researchers saw a decrease in the production of targeted repair proteins by approximately 90 percent, and were able to reduce the amount of radiation needed to damage cells. DeWeese's research team members are Spencer J. Collis, Ph.D., Michael J. Swartz, and William G. Nelson, M.D., Ph.D. Embargoed for Release Until Presentation on Monday, October 20th, 10:45 a.m., MT, Salt Palace Convention Center FIGHTING THE SIDE EFFECTS OF RADIATION If facing their cancer weren't enough, brain tumor patients undergoing radiation also risk life-threatening infections such as pneumonia as their immune systems are suppressed by the corticosteroids used to ward off brain swelling and treatment-related headaches. Johns Hopkins Kimmel Cancer Center radiation oncologists have found that monitoring patients' immune cell counts and prophylactic antibiotics help prevent potentially fatal side effects. The researchers measured the number of certain immune cells present in the blood of 82 brain cancer patients undergoing radiation therapy. Patients whose counts fell below a certain level (200/mm3) received prophylactic antibiotics. No patients developed pneumonia, other serious infections or side effects from the antibiotic. "It's important to follow how these patients react to the high levels of corticosteroids given during their treatment," says Lawrence Kleinberg, M.D., assistant professor of oncology and neurological surgery in the Department of Radiation Oncology at the Johns Hopkins Kimmel Cancer Center. In a future study, the research team will determine the most appropriate CD34 monitoring schedule. In addition to Kleinberg, the research team includes Michael A. Hughes, M.D, Michele Parisi, R.N., and Stuart A. Grossman, M.D. Embargoed for Release Until Presentation on Monday, October 20, Noon, MT, Salt Palace Convention Center