Risk higher for young women with Hodgkin disease treated with radiation.

2003 AUG 7 - (NewsRx.com & NewsRx.net) -- Young women with Hodgkin disease (HD) treated with chest radiation alone have an increased risk for breast cancer, according to a study in the July 23/30, 2003, issue of the Journal of the American Medical Association (JAMA).

A second cancer is the leading cause of death in long-term survivors of HD, with exceptionally high risks of breast cancer among women treated at a young age, researchers said.

Quantitative associations between radiotherapy dose delivered to the breast at ages 30 or less and administered chemotherapy have not been reported to date in large series, nor has the influence of ovarian exposures on subsequent risk. Increased rates of breast cancer have been generally attributed to chest irradiation for HD, consistent with the known sensitivity of the breast to ionizing radiation at young ages.

Lois B. Travis, MD, of the U.S. National Cancer Institute, National Institutes of Health, Bethesda, Maryland, and colleagues analyzed the risk of breast cancer among 3,817 women diagnosed with HD at age 30 or younger (between June 1965 and December 1994) and provided estimates of relative and absolute excess risk in terms of radiation dose delivered to the breast and the number of alkylating-agent (certain types of drugs that inhibit cell division and growth and are used to treat some cancers) cycles.

In an international investigation, the researchers studied 105 patients with HD who developed breast cancer and matched them with 266 patients with HD but without breast cancer.

"A radiation dose of 4 Gy or more delivered to the breast was associated with a 3.2-fold increased risk, compared with the risk in patients who received lower doses and no alkylating agents. Risk increased to 8-fold with a dose of more than 40 Gy. Radiation risk did not vary appreciably by age at exposure or reproductive history. Increased risks persisted for 25 or more years following radiotherapy [2.3-fold increased risk]," Travis and colleagues reported.

Treatment with alkylating agents alone resulted in a reduced risk (40%) of breast cancer, and combined alkylating agents and radiotherapy in a 1.4-fold increased risk. Risk of breast cancer decreased with increasing number of alkylating agent cycles. Risk also was low (60% reduced risk) among women who received 5 Gy or more delivered to ovaries compared with those who received lower doses.