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Radiation therapy's pivotal role in treating breast cancer featured at SABCS 2018

General session showcases major advances in radiation therapy for patients with breast cancer

American Society for Radiation Oncology

SAN ANTONIO, December 6, 2018 -- This year's San Antonio Breast Cancer Symposium (SABCS) features a record number of radiation oncology trials among its oral presentations. Today's General Session 4 (3:15-5:00 p.m. CT in Hall 3) will showcase five major studies designed to improve outcomes for the majority of breast cancer patients who receive radiation therapy to cure and/or provide relief from the disease.

"Breast cancer is the most common malignancy treated with radiation therapy in the United States," said Wendy A. Woodward, MD, PhD, Professor and Chief of the Clinical Breast Radiotherapy Service at the University of Texas MD Anderson Cancer Center. "Oncologists often prescribe radiation therapy to patients following breast cancer surgery to lower the chance of the cancer returning or spreading. Radiation therapy also can help women to preserve the breast and avoid axillary surgery." Dr. Woodward also will provide commentary when she moderates the session.

"This is a banner year for studies highlighting the efficacy of radiation oncology for breast cancer. A major emphasis in these trials is refining treatments to provide more options for patients, such as shorter courses of radiation therapy," added Reshma Jagsi, MD, DPhil, FASTRO, Professor and Deputy Chair of the Department of Radiation Oncology at the University of Michigan. Dr. Jagsi also will discuss over- and under-treatment in a session Friday at 2:15 p.m. CT in Hall 3.

Two studies from the session were featured in a SABCS press conference earlier today:

Three additional studies will be presented this afternoon:

  • Regional lymph node irradiation in early stage breast cancer: An EBCTCG meta-analysis of 13,000 women in 14 trials (abstract GS4-02)

    Key takeaway: Radiation therapy to the regional lymph nodes following breast cancer surgery improves long-term outcomes.

    A meta-analysis of 13,132 patient records from the Early Breast Cancer Trialists Collaborative Group (EBCTCG) finds that nodal irradiation reduced long-term breast cancer recurrence, cancer-specific mortality and overall mortality. Researchers found that these benefits were specific to women who enrolled in clinical trials within the last several decades, however. In older trials examined in the meta-analysis--those that began 1961-1978--nodal therapy did not impact recurrence or breast cancer mortality but increased the chance of non-cancer mortality.

    The different outcomes between modern and older trials reflect how radiation therapy has become substantially more precise over time, allowing more of the target dose to reach the lymph nodes rather than scatter to the heart. Researchers also compared findings for different regions of lymph nodes (axilla, supraclavicular fossa, internal mammary chain) but found no significant difference in recurrence rates.

  • RAPID: A randomized trial of accelerated partial breast irradiation using 3-dimensional conformal radiotherapy (3D-CRT) (abstract GS4-03)

    Key takeaway: Accelerated radiation therapy with 3D-CRT to just part of the breast is non-inferior to traditional radiation to the whole breast.

    A new report from the multi-center, randomized RAPID trial demonstrates that accelerated partial breast irradiation (APBI) with 3D-CRT is not inferior to standard treatment with whole breast irradiation (WBI) following breast-conserving surgery for early-stage breast cancer. Patients in both arms of the trial experienced similarly low rates of tumor recurrence in the treated breast at 5 and 8 years following treatment.

    APBI is a highly localized alternative to WBI where patients receive larger individual doses of radiation across fewer treatment sessions. Treatment with APBI typically takes a week or less, compared to three to six weeks for WBI. In this trial of 2,135 patients enrolled in three different countries, APBI was associated with less short-term toxicity but more long-term cosmesis and normal tissue side effects.

  • Dose escalated simultaneous integrated boost radiotherapy for women treated by breast conservation surgery for early breast cancer: 3-year adverse effects in the IMPORT HIGH trial (abstract GS4-05)

    Key takeaway: A radiation therapy regimen of dose-escalated, simultaneous integrated boost is safe and well-tolerated for early-stage breast cancer.

    A report from the multi-center phase III IMPORT HIGH trial shows that patients experienced similar adverse events following radiation therapy involving a dose-escalated simultaneous integrated boost as they did with standard treatment of whole breast radiation followed by a sequential boost. Three-year rates of moderate/severe long-term effects were low and generally similar across study groups, based on analysis of 2,617 women who received radiation following breast-conserving surgery for early-stage disease.

    By integrating boost with whole-breast radiation, the newer regimen allowed patients to receive treatment in 3 weeks, compared to 4.5 weeks with conventional treatment. According to the researchers, these data are the largest and most mature reported trial results for this treatment approach.

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Resources on breast cancer and radiation therapy:

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The American Society for Radiation Oncology (ASTRO) is the world's largest radiation oncology society, with more than 10,000 members who are physicians, nurses, biologists, physicists, radiation therapists, dosimetrists and other health care professionals who specialize in treating patients with radiation therapies. The Society is dedicated to improving patient care through professional education and training, support for clinical practice and health policy standards, advancement of science and research, and advocacy. ASTRO publishes three medical journals, International Journal of Radiation Oncology * Biology * Physics, Practical Radiation Oncology and Advances in Radiation Oncology; developed and maintains an extensive patient website, RT Answers; and created the nonprofit foundation Radiation Oncology Institute. To learn more about ASTRO, visit astro.org or RTanswers.org, sign up to receive our news and follow us on our blog, Facebook and Twitter.

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