The 54th Annual Meeting of the American Society for Radiation Oncology
The annual meeting of the American Society for Radiation Oncology was held from Oct. 28 to 31 in Boston and attracted approximately 11,000 participants from around the world, including physicians, oncology nurses, radiation therapists, biologists, physicists, and other cancer researchers. The conference featured educational courses focusing on radiation, surgical, and medical oncology. It also included more than 200 concurrent sessions and several general sessions as well as approximately 1,500 posters focusing on cancer research.
In one study, Alan J. Katz, M.D., J.D., of Flushing Radiation Oncology in Queens, N.Y., and colleagues found that stereotactic radiation therapy was just as effective, was associated with lower costs, and was more convenient than standard radiation therapy.
"Our study was completed at eight different sites and included 1,100 patients to evaluate the efficacy of CyberKnife stereotactic body radiation. The median follow-up was three years, but we had data out to five years. Our primary end point was biochemical control of disease or sustained decrease in prostate-specific antigen levels," Katz said. "We found that 94 percent of patients had biochemical control of the disease at five years, including 96 percent of low-risk patients, 92 percent of intermediate-risk patients, and 80 percent of high-risk patients. These results compare favorably to treatment with standard radiation; however, instead of giving 45 small doses daily, we gave patients five large doses of stereotactic radiation therapy."
Several authors disclosed financial ties to Accuray, manufacturer of the CyberKnife system
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In another study, Charles B. Simone II, M.D., of the University of Pennsylvania Hospital in Philadelphia, and colleagues evaluated whether radiation treatment in patients with breast cancer was associated with late cardiac toxicity. The investigators found that women who had undergone surgery and radiation did not experience an increased risk of late cardiac toxicity as compared to women who underwent surgery alone.
"To date, there has been conflicting data on whether radiation therapy could cause cardiac toxicity, with some smaller, single institution, older studies showing potential heart morbidity for women with left-sided tumors," Simone said. "Our study was the first randomized trial to comprehensively assess this topic, and we demonstrate a lack of late cardiac toxicity associated with radiation for breast cancer treatment. This should help to alleviate women's fears of cardiac toxicity following breast irradiation. Based on our findings, radiation therapy using modern treatment techniques to treat early-stage breast cancer is an effective and safe treatment modality, particularly from a cardiac standpoint."
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In a randomized controlled trial, Michael J. Zelefsky, M.D., of the Memorial Sloan Kettering Cancer Center in New York City, and colleagues evaluated whether daily administration of sildenafil citrate before and after radiation therapy in patients with prostate cancer was effective in preventing erectile dysfunction. The investigators found that patients who received the drug experienced improved sexual function as well as improved overall satisfaction with function compared to those who received placebo.
"Our study was a proof-of-principal study and our findings suggest that intervention with sildenafil during and after therapy leads to improved sexual function scores and helps maintain this function for at least two years after the therapy," Zelefsky said. "This was the first study to demonstrate this benefit among patients getting radiation treatments for prostate cancer. Further studies need to be completed to validate these findings and better understand what would be the optimal drug dosing, duration of treatment, and appropriate patients for treatment."
Two authors disclosed financial ties to Pfizer, the manufacturer of sildenafil citrate. Pfizer also provided the drug and placebo for the study.
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In a phase I dose escalation study, Rodney J. Ellis, M.D., of the Seidman Cancer Center/University Hospitals of Cleveland and Case Western Reserve University, and colleagues evaluated the efficacy and safety of stereotactic radiation therapy for the treatment of renal cell cancer.
"We found that 94 percent of patients had stable or regressing disease. However, among those biopsied, only two patients had a complete response to treatment. These biopsy results were not surprising though, as the trial was only evaluating very low doses of radiation initially," Ellis said. "In the current trial, we are using much higher doses of radiation and evaluating 12 new patients with doses ranging from 16 Gy ×3 to 18 Gy ×3 to 20 Gy ×3, which are doses that have been associated with cure rates equivalent to surgery in lung cancer treatment."
One author disclosed financial ties to Accuray, U.S. Endoscopy, and Varian Medical Systems.
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