AACR: Adjuvant Radiotherapy Increases Risk of Second Primary Cancer in Contralateral Breast By Peggy Peck Special to DG News SAN FRANCISCO, CA -- April 8, 2002 In a retrospective analysis of data from the National Cancer Institute's SEER database of women treated for localized unilateral invasive breast cancer or intraductal carcinoma in situ (DCIS), radiotherapy was associated with a 14 percent increase in the relative risk of second primary cancer in the contralateral breast. The finding was reported Sunday at the 93rd Annual Meeting of the American Association for Cancer Research. Xiang Gao, MD, PhD, of the Central Arkansas Radiation Therapy Institute, Little Rock, Arkansas said, however, that "even though there is an increased relative risk, the increase in absolute risk is very small. At 10 years the risk for second primary cancer in the contralateral breast is about 10 percent. Radiotherapy adds another one percent to that risk." But Dr. Gao said that the "real take home message for radio-oncologists is that this is another indication of the need to reduce unnecessary radiation exposure to the contralateral breast." The study includes SEER data on 115,606 women with newly diagnosed first primary localized unilateral invasive breast cancer and 18,895 DCIS patients. More than 900,000 person-years follow-up were available with 73,038 patients followed for 5 years and 31,354 followed for 10 years. Twenty-eight percent of the patients received radiotherapy. A contralateral breast cancer was documented in 4.2 percent of all patients studied. Dr. Gao said that radiotherapy was no associated with any increased risk during the first 5 years, but after five years women who had radiotherapy had an increased risk for developing cancer in the contralateral breast. Asked if the results could indicate selection bias, Dr. Gao said it is unlikely that only higher risk women received radiotherapy. But he did note that in the United States the decision about adjuvant radiation therapy "is often an access issue." Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.