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Accelerated Partial Breast Irradiation Using 3-D Conformal External Beam Radiation Therapy is Associated With a Negative Cosmetic Outcome Compared to Whole Breast Irradiation in Some Breast Cancer Patients

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BOSTON, Oct. 29, 2012 (GLOBE NEWSWIRE) -- Accelerated partial breast irradiation using 3-D conformal external beam radiation therapy is associated with a negative cosmetic outcome compared to whole breast irradiation in some breast cancer patients

Boston, October 29, 2012-Accelerated partial breast irradiation (APBI) with 3-D external beam radiation therapy (3-D CRT) for breast cancer patients who have undergone breast conserving surgery (BCS) yields worse cosmetic outcomes than whole breast irradiation (WBI), according to research presented today at the American Society for Radiation Oncology's (ASTRO's) 54th Annual Meeting.

Radiation can cause fibrosis or thickening of breast tissue, which can lead to distortion of the treated breast after surgery and can adversely affect a patient's cosmetic result. This study reports on the interim toxicity results of a multi-center, randomized trial comparing 3-D CRT APBI to standard WBI in breast cancer patients previously treated with BCS. The study includes 2,135 women over the age of 40 who had invasive or non-invasive breast cancer less than three centimeters in size and were treated with BCS between February 2006 and July 2011. Patients were randomized into two groups: those who were given 3-D CRT APBI of 38.5 Gy in 10 fractions twice daily, and those who received WBI of 50 Gy in 25 fractions or 42.5 Gy in 16 fractions given once daily +/- boost irradiation.

Cosmetic outcome (cosmesis) was assessed by a trained study nurse and the patients at baseline, three and five years after treatment as well as by a panel of radiation oncologists who reviewed unlabeled digital photographs. Patient results for cosmesis were rated using the European Organisation for Research and Treatment of Cancer (EORTC) Cosmetic Rating System for Breast Cancer and for toxicity using the NCI Common Terminology Criteria for Adverse Events (v. 3). Negative cosmesis results were compiled for ratings of at least "fair" or "poor" versus "very good" or "excellent." The study is still in process and reports an interim safety analysis at a median follow-up of 2.5 years. At three years post-treatment 850 patients were assessed by nurses. Thirty-two percent of patients were observed to have adverse cosmesis with APBI in comparison to 19 percent of patients treated with WBI. Oncologists and patients provided similar assessments in the rate of observed adverse cosmesis with APBI vs. WBI. Grade 1 and 2 late radiation toxicities, such as breast induration, were higher in the group receiving APBI compared to those receiving WBI. Grade 3 and 4 toxicities were rare in both treatment groups.

"Women with early-stage breast cancer who undergo breast conserving surgery may be offered accelerated partial breast irradiation as part of their treatment," said Timothy J. Whelan, MD, lead author of the study and a radiation oncologist at Juravinski Cancer Centre in Hamilton, Ontario. "Our study supports earlier Phase II trial research and found that APBI using 3-D external beam radiation therapy can increase the risk of moderate radiation side effects, which may affect cosmetic outcome for some patients. 3-D CRT APBI treatment needs additional research."

The abstract, "Interim Toxicity Results from RAPID: A Randomized Trial of Accelerated Partial Breast Irradiation (APBI) Using 3-D Conformal External Beam Radiation Therapy (3-D CRT)," will be presented in detail during the plenary session at ASTRO's 54th Annual Meeting at 2:30 p.m. Eastern time on Monday, October 29, 2012. To speak with Dr. Whelan, call Michelle Kirkwood on October 28 - 31, 2012, in the ASTRO Press Office at the Boston Convention and Exhibition Center at 617-954-3461 or 617-954-3462, or email michellek@astro.org.

ASTRO's 54th Annual Meeting, held in Boston, October 28 - 31, 2012, is the premier scientific meeting in radiation oncology and brings together more than 11,000 attendees including oncologists from all disciplines, medical physicists, dosimetrists, radiation therapists, radiation oncology nurses and nurse practitioners, biologists, physician assistants, practice administrators, industry representatives and other health care professionals from around the world. The theme of the 2012 Annual Meeting is "Advancing Patient Care through Innovation" and examines how innovation in technology and patient care delivery can lead to improved patient outcomes. The four-day scientific meeting includes six plenary papers and 410 oral presentations in 63 oral scientific sessions, and 1,724 posters and 130 digital posters in 18 tracks/topic areas.

ABOUT ASTRO

ASTRO is the largest radiation oncology society in the world, with more than 10,000 members who specialize in treating patients with radiation therapies. As the leading organization in radiation oncology, biology and physics, the Society is dedicated to improving patient care through education, clinical practice, advancement of science and advocacy. For more information on radiation therapy, visit www.rtanswers.org. To learn more about ASTRO, visit www.astro.org.

2012 American Society for Radiation Oncology (ASTRO) 54th Annual Meeting
News Briefing, Tuesday, October 30, 2012, 7:00 a.m. - 7:45 a.m. Eastern time

Scientific Session: Monday, October 29, 2012, 2:30 p.m. - 3:45 p.m. ET, Boston Convention & Exhibition Center

LBA1 Interim Toxicity Results from RAPID: A Randomized Trial of Accelerated Partial Breast Irradiation (APBI) Using 3-D Conformal External Beam Radiation Therapy (3-D CRT)

T. J. Whelan1, I. Olivotto2, S. Parpia3, T. Berrang2, D. Kim1, I. Kong1, P. Truong2, B. Cochrane3, J. Julian3, &. RAPID Trial Investigators4, 1Juravinski Cancer Centre, Hamilton, ON, Canada, 2BC Cancer Agency, Victoria, BC, Canada, 3McMaster University, Hamilton, ON, Canada, 4Ontario Clinical Oncology Group, Hamilton, ON, Canada

Purpose/Objective(s): Women with early stage breast cancer treated by breast conserving surgery (BCS) are increasingly offered APBI in the community despite limited evidence regarding efficacy and safety from randomized trials. Some phase II studies have reported increased toxicity from APBI using 3-D CRT. We report the interim toxicity results of a multicenter randomized trial comparing 3-D CRT APBI to standard whole breast irradiation (WBI).

Materials/Methods: Women > 40 years of age with invasive or non-invasive breast cancer less than 3 cm treated by BCS were randomized to 3-D CRT APBI (38.5 Gy in 10 fractions given twice daily) or WBI (50 Gy in 25 fractions or 42.5 Gy in 16 fractions given once daily ± boost irradiation). The primary outcome was ipsilateral breast tumour recurrence and important secondary outcomes were adverse cosmetic outcome (fair or poor on a global assessment using the EORTC Cosmetic Rating System for Breast Cancer) and toxicity using the NCI Common Terminology Criteria for Adverse Events 3.0. Cosmesis was assessed directly by a trained study nurse and the patient at baseline, 3 and 5 years post-randomization. Cosmesis was also assessed by a trained panel of radiation oncologists unaware of treatment allocation using digital photographs. Radiation toxicity was assessed by the study nurse during radiotherapy and in follow-up. The events required for the interim efficacy analysis have not been reached; however, the interim safety analysis based on the nurse-assessed adverse cosmesis was performed as planned after a median follow-up of 2.5 years. Upon review of the data, the Data Safety Monitoring Committee recommended release of the results.

Results: Between February 2006 and July 2011, 2135 women were randomized to 3-D CRT APBI or WBI. There was an increased rate of adverse cosmesis at 3 years by nurse assessment in patients treated with APBI compared to WBI (see table, p less than 0.0001). Adverse cosmesis was also increased with APBI vs. WBI whether assessed by the patient (26.2% vs. 18.4%, p=0.004) or oncologist panel (35.1% vs. 16.6%, p less than 0.0001). In addition, grades I and II late radiation toxicities were increased in the APBI arm compared to the WBI arm; grades III and IV were rare in both treatment groups.

Conclusions: In patients who have undergone BCS, APBI delivered by 3-D CRT was associated with worse cosmetic outcome and late radiation changes at 3 years compared to WBI. These results have implications for decision-making in patients considering 3-D CRT APBI off-trial.

CONTACT: Michelle Kirkwood 703-286-1600 michellek@astro.org
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