Breast Cancer Risk Found High After Chest Radiation for Hodgkin's

Young women treated with high-dose chest radiation for Hodgkin's lymphoma have 10 times or greater the risk of developing Breast cancer later in life than do women in the general population.

That cumulative absolute risk assessment emerged from an analysis of data from a population-based cohort of 3,817 women diagnosed and treated for Hodgkin's lymphoma between 1965 and 1994.

It contrasts with previous estimates of the cumulative incidence of Breast cancer after treatment of young women for Hodgkin's disease, ranging from 4.2% to 34% at 20 to 25 years of follow-up, reported Lois B. Travis, M.D., of the National Cancer Institute here and colleagues.

They characterized the previous risk estimates as smaller and not likely to be as accurate.

For women treated at age 25 with a chest radiation dose of 40 Gy or more without alkylating agents, Dr. Travis and colleagues reported in the Oct. 5 issue of the Journal of the National Cancer Institute, the cumulative absolute risk of developing Breast cancer at key ages, versus risk in the general population, was:

• Age 35: 0.4% (95% confidence interval=0.3%-0.6%) versus 0.04% for the general population.
  
• Age 45: 4.9% (95% CI=3.2%-7.4%) versus 0.5% for the general population.
  
• Age 55: 29.1% (95% CI=13%-27.4%) versus 2% for the general population.
  

They found that cumulative absolute risks were lower in women treated with alkylating agents, a 40% reduction in Breast cancer risk.
Breast cancer is a malignant growth that begins in the tissues of the breast. Over the course of a lifetime, one in eight women will be diagnosed with breast cancer.

Causes, incidence, and risk factors

There are several different types of breast cancer. Ductal carcinoma begins in the cells lining the ducts that bring milk to the nipple and accounts for more than 75% of breast cancers.

Lobular carcinoma begins in the milk-secreting glands of the breast but is otherwise fairly similar in its behavior to ductal carcinoma. Other varieties of breast cancer can arise from the skin, fat, connective tissues, and other cells present in the breast.

"It is sobering to realize that, by age 50 years, many of the women treated with high-dose chest radiotherapy had already exceeded the lifetime risk of developing Breast cancer in the general population (in which one in eight women will develop , or 13.4%)," they wrote.