Reiner AS, Watt GP, John EM, et al. - A multicenter, individually-matched case-control study was performed to explore the relationship between radiation therapy (RT), smoking, and risk of contralateral breast cancer (CBC). Researchers enrolled 1,521 CBC cases and 2,212 controls with unilateral breast cancer; first invasive breast cancer was diagnosed in all between 1985–2008 at age < 55 years. They calculated absorbed radiation doses to contralateral breast regions with thermoluminescent dosimeters in tissue-equivalent anthropomorphic phantoms and smoking history was collected by interview. No evidence was found that RT further elevated CBC risk in young women with first primary breast cancer who were current smokers or had a smoking history.