Women who have radiation on left breast 2 times as likely to develop this

By Georgia Lambert via SWNS

A new study says young women are twice as likely to develop heart disease if they have radiation therapy to treat cancer in the left breast rather than the right.

Radiation therapy is a widely-used treatment for breast cancer and while the benefits of the therapy are clear, long-term complications related to radiation therapy may still occur.

Scientists at the Memorial Sloan Kettering Cancer Center found that women with left-sided breast cancer undergoing radiation therapy between the years 1985 and 2008 suffered twice the risk of coronary artery disease, compared to women with right-sided breast cancer.

"Nearly half of women diagnosed with breast cancer will undergo radiation therapy, which may expose the heart to incidental radiation," said study author Gordon Watt, a doctoral research fellow.

"For those who are under 50 years old when diagnosed with breast cancer, their 10-year survival rate is over 90% for Stage I disease and more than 75% for Stage II disease.

“Our study adds to the growing evidence that left-sided radiation therapy is an independent risk factor for future heart disease after treatment for breast cancer.

"It is important that clinicians caring for younger breast cancer patients communicate the importance of radiation therapy for breast cancer while explaining the need for long-term attention to the risk of heart disease, particularly for women receiving left-sided radiation therapy.

"Radiation therapy is an indispensable part of breast cancer care, and the good news for breast cancer patients is that modern techniques and computerised treatment planning have reduced the amount of radiation that reaches the heart, thereby reducing the risk of developing heart disease.”

Researchers studied participants in the Women’s Environmental Cancer and Radiation Epidemiology Study to evaluate the risk of coronary artery disease in breast cancer survivors.

The team excluded anyone who had pre-existing cardiovascular diseases and was left with a sample group of 972 women.

All the participants were diagnosed with breast cancer between 1995 and 2008, were under 55-years-old and had completed a cardiovascular health questionnaire.

Clinical and lifestyle factors were taken into account and the average health follow-up time was measured at a period of 14 years.

Radiation-associated heart disease has a latency of at least five years, meaning that in order to safeguard breast cancer survivors, long-term follow-up is needed.

Data collected from previous studies in older populations have shown left-sided radiation therapy is associated with an increased risk of developing heart disease - although the level of risk was varied between studies.

According to the scientists, after receiving radiation therapy, the risk of heart disease had not been previously evaluated for younger demographics.

The study, published in the journal JACC: CardioOncology showed that in the 27.5 years of follow-up appointments, the overall incidence of coronary artery disease in women who had received radiation therapy in their right breast was 5.8%.

The figure had almost doubled in women who had received treatment in their left breast, at 10.5%.

For women diagnosed between the ages of 25 and 39-years-old in the study’s sample group, those who received left-sided radiation therapy, had a 5.9% incidence of coronary artery disease, while those receiving right-sided radiation therapy reported no such occurrence of the disease.

In an accompanying editorial document doctors, Professor James Bates, Associated Professor Ming Hui Chen, and Dr Louis Constine wrote: “This study also reaffirms the role of prolonged surveillance for coronary artery disease in younger survivors.

"Given the latency between radiation exposure and development of cardiovascular events, it is important that young women who have received left breast radiation therapy be considered at higher risk over their lifetime.”

Although the study had limitations, the authors note that, since the study period, radiation therapy techniques have been refined to further reduce the incidental radiation exposure to the heart.