With recent studies showing potentially dangerous links between breast cancer patients who undergo radiation therapy and develop heart problems later in life, the development of targeted therapies is among the top priorities of today’s radiation oncologists.
Last week, we spoke to Baldassarre Stea, MD, PhD, FASTRO, the UA Cancer Center’s Head of Radiation Oncology, about the department's use of a technique known as respiratory gating, a technology that enables clinicians to track a tumor’s position in relation to the patient’s respiratory cycle. This targeted therapy technique spares the heart and focuses the radiation beam specifically on cancerous cells. Read that story on the UA Cancer Center's official website.
Today, Victor Gonzalez, MD, discusses the UA's ongoing efforts to protect breast cancer patients.
This study is important for several reasons. On one hand, it shows us how far radiation techniques have advanced in breast cancer. The doses of radiation to the heart with modern techniques are dramatically lower than they were twenty years ago, when most of the women in this study were treated.
At the same time, it emphasizes the need for continued improvement and ongoing research. Right now, we don’t know what dose of radiation is 100 percent safe for the heart. We can assume that the risk to the heart is going to be less with modern techniques, but we don’t know if that will be enough to completely eliminate the risk.
Patients who may see the greatest risk for treatment are women with left-sided tumors and women who require radiation to the lymph nodes close to the heart. In this situation, the heart can temporarily be moved away from the ribcage by having the patient take a deep breath, moving the ribcage and the breast away from the heart. Special cameras located in the radiation treatment room track the patient’s breathing cycle, which is displayed to the patient on special video goggles. The radiation beam is automatically turned on only after the heart had moved safely out of the way.
Dr. Gonzalez emphasized that the UACC is the only center in Tucson, and among only a handful of Cancer Centers in the United States, with this technology.
It is important to point out that the risk of heart injury from breast radiation is still small. As an example, 4-5 of every 100 women who are 50 years old and without any risk factors for heart disease would have a heart attack by age 80 without radiation. If this same group of 100 women received a typical course of breast radiation, one additional patient would have a heart attack. For comparison, smoking, diabetes and obesity each increased the risk of heart disease more than radiation therapy.
We have to balance the potential risks of treatment with the known benefits. After breast cancer surgery, radiation cuts the odds of the cancer returning in half. For most women, that’s going from a 30 percent chance of cancer without radiation to a 15 percent chance of cancer with radiation. There is no doubt that radiation therapy for breast cancer is a life-saving treatment. Overall, the benefits far outweigh the risks.
(ArizonaCancerCenter.org, March 15, 2013)