(RxWiki News) Ductal carcinoma in situ (DCIS), a condition where there are abnormal breast cells considered to be a precursor to breast cancer, has traditionally been treated with surgery, followed by radiation. There has been concern that the radiation could increase heart disease risks among DCIS survivors.
A large, long-term study offers both good news and relief for DCIS survivors.
Compared to the general population or DCIS survivors treated only with surgery, radiotherapy did not increase the risk of cardiovascular disease among DCIS survivors, the study found.
"Ask a lot of questions about your cancer treatment."
Naomi B. Boekel, MSc, a PhD student at the Netherlands Cancer Institute in Amsterdam, was the lead author of this study, which was conducted to see if radiation therapy increased heart disease risks among women treated for DCIS.
Ductal carcinoma in situ develops in the ducts that carry milk. The abnormal cells (lesion) of DCIS are considered a precursor of breast cancer and, if untreated, may possibly progress into invasive breast cancer.
Traditional treatments for DCIS have included either a mastectomy (removal of the breast), or more recently, a lumpectomy, which removes the lesion. Radiation is used after a lumpectomy to remove any remaining cancer cells.
Earlier research has shown that radiation can increase the long-term risks of heart disease.
For this study, the research team gathered information on 10,468 Danish women diagnosed with DCIS between 1989 and 2004.
Of this group, 28 percent had both surgery and radiotherapy.
The researchers compared heart disease risks among DCIS survivors treated with radiotherapy and the general population, as well as DCIS survivors who did not receive radiation.
Participants were followed for a median (middle) of 10 years, and the researchers discovered the following:
- DCIS survivors had a 30 percent lower chance of dying from heart disease than Dutch women with no history of cancer.
- Incidence of cardiovascular disease was similar between women treated with surgery alone (9 percent) and those who had both surgery and radiation therapy (8 percent).
- 7 percent of the women who received radiation to the left breast, closest to the heart, developed heart disease later in life, compared to 8 percent of women who had right-sided radiation.
- Women who had been diagnosed with heart disease two years before their DCIS diagnosis did have greater risks of cardiovascular disease later in life.
It’s not clear exactly why DCIS survivors had lower overall heart disease risks than the general population. Boekel said the difference may be because the survivors were more health conscious and had healthier lifestyles following their cancer diagnosis. Other variables, such as age of menopause or other risk factors, may also play a role in this difference, according to Boekel.
Frank Vicini, MD, FACR, Radiation oncologist at 21st Century Oncology in Royal Oak, MI, told dailyRx News, “This large study confirms what we previously believed — that modern radiotherapy for breast cancer does not increase the risk of cardiovascular disease.”
He continued, “These critical data should go a long way to reassure patients and healthcare providers that appropriately selected women can be treated safely with radiation for breast cancer and that long-term data now confirm they do not need to be concerned about any potentially harmful effects on their hearts.”
Controversy has swirled around the overdiagnosis and overtreatment of DCIS. Some women and physicians are choosing a wait-and-see approach instead of treating DCIS right away.
Boekel said the findings of this study are "...especially important in light of the current concerns about overtreating patients diagnosed with DCIS.”
Results from this study were presented at the 2013 Breast Cancer Symposium.
All research is considered preliminary before it’s published in a peer-reviewed journal.