25 Years After Breast Cancer Treatment, Patients Who Received Radiation Therapy do Not Have a Higher Risk of Heart Problems

First Long-Term Study Confirms Radiation Treatment is Beneficial and Safe

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| Source: American Society for Radiation Oncology

BOSTON, Oct. 29, 2012 (GLOBE NEWSWIRE) -- Breast cancer patients who receive radiation treatment do not have a higher risk of long-term cardiac morbidity when compared to patients undergoing modified radical mastectomy (MRM), according to research presented today at the American Society for Radiation Oncology's (ASTRO's) 54th Annual Meeting. This is the first study to document comprehensive, late cardiac outcomes 25 years after breast cancer treatment.
   
The study reviewed 247 stage I-II breast cancer patients who were enrolled in the National Cancer Institute (NCI) Breast Conservation Trial from 1979 to 1987 and found that 102 were alive 25.7 years after treatment. Fifty of those patients participated in this study, 26 of whom underwent breast conservation therapy (BCT) using radiation and 24 of whom underwent MRM. Patients were evaluated based on a detailed cardiac history, exam, cardiac labs and 3T cardiac MRI (CMR) to assess anatomic and functional abnormalities, as well as a CT angiogram to evaluate for stenotic coronary disease and determine if there was a high coronary arterial calcium score (CAC) for atherosclerosis. Imaging was assessed by a single experienced cardiologist blinded to each randomization arm.
     
Patient characteristics, exam findings and lab results were statistically similar for patients treated with MRM alone and those treated with BCT using radiation therapy, although BCT patients had somewhat lower rates of diabetes at 3.8 percent versus 12.5 percent for MRM patients. Systolic blood pressure rates were 127mm Hg versus 139mm Hg for BCT and MRM patients, respectively. Radiation treatment on patients' right versus left breast showed no difference in the relevance, severity or distribution of atherosclerosis for BCT patients, including the left anterior descending coronary artery, which is in close proximity to the chest wall and received the highest radiation dose.
     
Using the Framingham model to assess a patient's potential risk of developing myocardial infarction (MI) within 10 years of diagnosis and treatment, the study found similar rates between groups—the risk was 5.1 percent for BCT patients and 5.7 percent for MRM patients. Two MRM patients had a prior MI and one had heart failure. Diastolic function, including peak filling rate and diastolic volume recovery, was similar for both patient groups. Other similarities in the CMR findings included peak mid-wall strain and chamber mass, volume and function. The median coronary arterial calcium score (CAC) was similar in both groups at 25 for BCT patients and 0 for MRM patients, which are both in the normal range. No patients exhibited myocardial fibrosis, and one patient in each group experienced pericardial thickening. Among BCT patients, cardiac structure and function were similar for right- or left-breast tumors. BCT patients underwent radiation doses of 45 to 48.6 Gy to the whole breast, with a 15 to 20 Gy boost to the tumor bed. The study authors did find that visible atherosclerosis occurred somewhat more often among those receiving chemotherapy for both MRM and BCT patients.
     
"Over the past two decades, radiation therapy has become more precise and safer with modern techniques," said Charles B. Simone II, MD, lead author of the study and a radiation oncologist at the Hospital of the University of Pennsylvania in Philadelphia. "We are pleased to find that early stage breast cancer patients treated with modern radiation therapy treatment planning techniques do not have an increased risk of long-term cardiac toxicity and that breast conservation therapy with radiation should remain a standard treatment option."
     
The abstract, "Cardiac Toxicity is Not Increased 25 Years After Treatment of Early-stage Breast Carcinoma with Mastectomy or Breast Conservation Therapy from the National Cancer Institute Randomized Trial," will be presented in detail during a scientific session at ASTRO's 54th Annual Meeting at 11:00 a.m. Eastern time on Monday, October 29, 2012. To speak with Dr. Simone, 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, October 30, 2012, 7:00 a.m. – 7:45 a.m. Eastern time

Scientific Session: October 29, 2012, 11:00 a.m. – 12:30 p.m. ET, Boston Convention & Exhibition Center

87 Cardiac Toxicity is Not Increased 25 Years After Treatment of Early-stage Breast Carcinoma with Mastectomy or Breast Conservation Therapy from the National Cancer Institute Randomized Trial

C. B. Simone1, C. Sibley2, T. D. Dan3, D. M. Boyce4, S. Smith3, M. Lippman5, E. Glatstein1, D. A. Bluemke2, K. Camphausen6, N. L. Simone7, 1Hospital of the University of Pennsylvania, Philadelphia, PA, 23Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, MD, 3National Cancer Institute, Radiation Oncology Branch, Bethesda, MD, 44Johns Hopkins University School of Medicine, Pulmonary and Critical Care Medicine, Baltimore, MD, 55University of Miami Health System, Department of Medicine, Division of Hematology/Oncology, Miami, FL, 62National Cancer Institute, Radiation Oncology Branch, Bethesda, MD, 7Thomas Jefferson University Hospital, Department of Radiation Oncology, Philadelphia, PA

Purpose/Objective(s): Assessment of late cardiac toxicity from the National Cancer Institute (NCI) randomized trial of breast conservation therapy (BCT) vs. modified radical mastectomy (MRM).

Materials/Methods: 247 stage I-II breast cancer pts treated from 1979-1987 at NCI were randomized to BCT (45-48.6 Gy whole breast, 15-20 Gy boost) or MRM. Node positive pts received doxorubicin and cyclophosphamide. 102 pts were alive at 25.7 yrs, and 50 pts (26 BCT, 24 MRM) participated in this prospective IRB-approved study with a detailed cardiac history, exam, cardiac labs, 3T cardiac MRI (CMR) to evaluate for anatomic and functional abnormalities, and CT angiogram to evaluate for stenotic coronary disease and determine coronary arterial calcium score (CAC) of atherosclerotic burden. Imaging was assessed by a single experienced cardiologist blinded to randomization arm.

Results: Pt characteristics, exam findings, and labs were similar between arms, although MRM pts trended to have higher systolic blood pressures (SBP, 139 mmHg vs. 127 mmHg) and rates of diabetes (12.5% vs. 3.8%, p=0.27). Among BCT pts, radiation central lung distance >3 cm was similar for right- vs. left-sided tumors (35.7% vs. 50.0%, p=0.48). Cardiac interventions (CABG or PCI) occurred in 4 MRM and 3 BCT pts. Two pts had prior myocardial infarction (MI) and one had heart failure (all MRM pts). Framingham 10-yr risk of MI was similar between arms (BCT 5.1 vs. MRM 5.7%). CMR showed lower ventricular mass in BCT pts (91 vs. 110 gm, p=0.02) that was not significant after adjusting for SBP. Diastolic function, including peak filling rate (p=0.29) and diastolic volume recovery (p=0.28), was similar between arms. Other CMR findings, including peak midwall strain and chamber mass, volume and function, were similar between arms. No pt had evidence of myocardial fibrosis. One pt in each arm had pericardial thickening. Among BCT pts, cardiac structure and function were similar for right or left tumors. Median CAC was similar in both arms [BCT 25 (IQR 0, 86) vs. MRM 0 (IQR 0, 354), p=0.65]. BCT pts had no increase in visible atherosclerosis (HR 1.12, p=0.80) or luminal stenosis >50% (HR 0.64, p=0.62). Prevalence, severity and distribution of atherosclerosis were not different in BCT pts for right- or left-sided radiation, including LAD (close proximity to the chest wall, received the highest RT dose) (38.9% vs. 33.3%, p=0.73). Chemotherapy pts trended towards more visible atherosclerosis independent of randomization arm (HR 2.4, p=0.07).

Conclusions: This is the first study to report comprehensive late cardiac outcomes after randomization for breast cancer therapy. Based on this study, in the era of 3D planning, pts treated with breast radiotherapy do not have a higher risk of long-term cardiac morbidity compared with MRM pts.

Author Disclosure Block:

C.B. Simone: None. C. Sibley: None. T.D. Dan: None. D.M. Boyce: None. S. Smith: None. M. Lippman: None. E. Glatstein: None. D.A. Bluemke: None. K. Camphausen: None. N.L. Simone: None.

Michelle Kirkwood
703-286-1600