For Breast-Conservation Therapy, More Intense Hypofractionation Has Less Toxicity, Same Control

FigureSAN FRANCISCO—A more intense radiation treatment that completes therapy more quickly may be less toxic than conventional radiation used to treat women undergoing breast-conservation therapy, researchers reported here at the American Society for Radiation Oncology Annual Meeting. The data were from interim results of a randomized Conquer Cancer Foundation/Breast Cancer Research Foundation-sponsored trial, and found that the shorter hypofractionated radiation treatment resulted in less fatigue, and remarkably, fewer adverse events. “Six months after completing radiation, hypofractionated whole-breast irradiation results in lower rates of patient reported and physician-reported fatigue as well as a trend toward improved physical well-being,” Simona Shaitelman, MD, EdM, Assistant Professor of Radiation Oncology at the University of Texas MD Anderson Cancer Center, said in her oral presentation of the Late-Breaking abstract. She reported the following results: At six months, 23 percent of women who underwent hypofractionated whole-breast irradiation reported lack of energy due to fatigue compared with almost 40 percent of the women who received conventional radiation, while at baseline, 38.5 percent of patients receiving conventional radiation therapy and 38.4 percent of women assigned to hypofractionated radiation therapy had reported lack of energy on the FACT-B scale; At six months, the Mean Physical Wellbeing Score among women treated with conventional radiation regimens was 24.7 (same as a baseline) compared with 25.4 (slight increase from the 24.7 baseline score) for those receiving the hypofractionated whole-breast irradiation schedule; A lower percentage of women receiving the hypofractionated radiation treatment developed Grade 2 or worse adverse events: about 46.4 percent vs. about 78 percent of those undergoing conventional radiation; Any acute Grade 3 or worse adverse event was experienced by 5.4 percent of the women treated with conventional radiation compared with none of the women getting hypofractionated therapy; and Women undergoing hypofractionated radiation therapy had statistically less pruritus, breast pain, dermatitis, and hyperpigmentation. For the trial, Shaitelman and colleagues evaluated 432 women, and registered 300 of these women for the protocol. Thirteen withdrew before beginning treatment—including eight women who found out that their insurance would not cover the protocol. A total of 149 women were assigned to conventional radiation protocols and 138 to hypofractionated protocols. The data Shaitelman reported at the meeting were on 141 women who had completed six months of follow-up after being treated with conventional radiation and 123 women who were treated following the hypofractionated treatment scheme.SIMONA SHAITELMAN, MD, EDM. SIMONA SHAITELMAN, MD, EDM: “Six months after completing radiation, hypofractionated whole breast irradiation results in lower rates of patient-reported and physician-reported fatigue as well as a trend toward improved physical well-being.”More Convenient Asked for his opinion for this article, Kenneth Roberts, MD, Professor of Radiation Oncology at the Yale School of Medicine, noted that there have been several randomized studies that have shown equivalent outcomes in terms of cancer control with a hypofractionated regimen—“this had been promulgated by folks from Canada and Great Britain, where there are different practice patterns and a desire to get treatments done more quickly. Since those studies have come out, hypofractionated radiation therapy has become more of a standard of care as long as the dose of radiation in the treatment plan isn't excessive.” He said the results of the new study do appear to counter a lot of training of many radiation oncologists—“including myself”—in that the faster treatment course had actually lower toxicity. “That is more impetus for promoting a quicker treatment course. Women don't have to go through a five- to six-week course of treatment; it can be a four-week schedule. This is more convenient for patients, and it has the same cancer-control outcomes and less toxicity, according to this study.” Secondary Endpoints Reporting the secondary endpoints of the study—soft tissue toxicities and quality of life—Shaitelman explained that acute toxicities were collected using the Common Terminology Criteria for Adverse Events (CTCAE) Version 4. Short-term toxicities were recorded using the CTCAE Version 4; the LENT-SOMA (late effects in normal tissues subjective, objective, management and analytic scales), and the FACT-B (Functional Assessment of Cancer Therapy-Breast) scale. The researchers focused on the Physical Well Being Component of the FACT-B, which was a scale of 0 to 4 dealing with energy, pain, adverse events, and ability to perform activities of daily living. Study Details The conventional radiation treatment involved 30 to 32 days of radiation treatment during which the women received a dose of 10 Gy in five fractions if the surgical margin was 2 mm or more and 14 Gy in seven fractions if the margin was less than 2 mm. The hypofractionated therapy involved a dose of 10 Gy in four fractions if the surgical margin was 2 mm or more, and 12.5 Gy in five fractions if the margin was smaller. Treatment was completed in 20 to 21 days. Patients were eligible for participation in the study if they had been diagnosed with Stages Tis-T2, N0-N1, M0 breast cancer and wished to have breast-conserving therapy. Women with invasive breast cancer underwent axillary staging. Patients had to be older than 40, and were ineligible if they had a prior history of breast cancer. The patients were stratified for multiple factors, including bra cup size, whether they received chemotherapy, margin status, baseline physician-assessed cosmesis, sites where treatment was performed, age distribution (70 percent of patients were age 50 to 69), race, menopausal status (88 percent of the women were postmenopausal), body mass index (nearly 75 percent were considered overweight or obese), and various tumor characteristics. All of the differences between the patients receiving conventional fractionation and those receiving hypofractionation were similar. Shaitelman noted that there was a trend for more of the women in the hypofractionated radiation study group to have invasive cancer compared with those who had ductal carcinoma in situ. A total of about 83 percent of the women receiving hypofractionated radiation therapy were diagnosed with invasive cancer compared with about 74 percent of those receiving conventional therapy. Comparisons of Toxicities “There have been at least four large randomized controlled trials comparing hypofractionated versus standard fractionated breast radiation therapy,” she said. “These trials have demonstrated that over a 10-year follow-up these two fractionation regimens resulted in equal rates of local control, overall survival, and cosmesis.” Roberts said that one of the strengths of the new study is that it included comparisons of toxicities. “We are moving towards hypofractionated radiation therapy in breast cancer, and this study actually promotes it use. This is just more evidence that hypofractionated radiation regimens may be more appropriate for many women.”

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