NEW YORK (Reuters Health) - Cigarette smoking dramatically increases the risk that a woman who has undergone radiation treatment for breast cancer will develop lung cancer later on, a new study shows.
Radiation after mastectomy may be considered for some high-risk breast cancer patients, Dr. Elizabeth L. Kaufman and colleagues from Columbia University in New York City point out in their report. However, radiation can cause many complications, including increasing the likelihood that a patient will develop lung cancer 10 or more years after treatment, they add.
An earlier, small study by Kaufman and her team had suggested that cigarette smoking could boost this risk even more. To investigate further, she and her colleagues looked at breast cancer patients included in the Connecticut Tumor Registry who had been diagnosed with the disease between 1965 and 1989. They compared 113 women who had developed lung cancer 10 or more years after their breast cancer diagnosis with 364 women who did not.
Non-smoking women who had undergone radiation were no more likely than those who hadn’t had radiation therapy to develop lung cancer, the researchers found. However, women who smoked but didn’t have radiation therapy were nearly six times as likely to be diagnosed with lung cancer than non-smokers who didn’t have radiation, while women who smoked and did undergo radiation therapy were at nearly 19-fold greater risk.
Combined smoking and radiation therapy increased the risk that a woman would develop cancer in the lung on the same side of the body as her affected breast nearly 38-fold, while the risk of developing cancer in the opposite lung was more than 10-fold greater.
The findings suggest, the researchers say, that women who have smoked and undergone radiation therapy for breast cancer should undergo screening for lung cancer using a scanning technique called spiral computed tomography.
Furthermore, doctors should consider a patient’s smoking history when discussing her breast cancer treatment options, they add, especially if radiation may offer only a “marginal” survival advantage.
SOURCE: Journal of Clinical Oncology, January 20, 2008.