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.
The study reviewed here reinforces the results of earlier research: besides causing many diseases and increasing breast cancer risk, smoking can increase complications from radiation therapy.
In this study, women who smoked and received radiation to treat breast cancer had a much higher risk of developing lung cancer compared to women who didn't smoke and received radiation. Women who didn't smoke and had radiation to treat breast cancer were no more likely to develop lung cancer than women who didn't have radiation.
Smoking by itself increases lung cancer risk. This study found that smokers who didn't get radiation therapy were 6 times more likely than average to develop lung cancer.
This research looked at women who received breast cancer radiation therapy between 1965 and 1989. Because of improvements in the way radiation therapy is delivered, it's likely that the increase in lung cancer risk after radiation is less today than what's reported in the study. Advances in technology make it much less likely that lung and other tissues will be exposed to radiation during breast cancer treatment. Computers are used to plan radiation treatment that is extremely precise. The computer aims just the right amount of radiation only at tissue that needs to be treated. Other new technology gives radiation oncologists a wider and safer choice of radiation energy sources. Together, these two advances help the radiation oncologist avoid exposing the lungs to radiation intended only for the breast area.
If you smoke and have been diagnosed with breast cancer, please consider the following:
It can be very hard to stop smoking. But quitting is something you can control that can make a big difference in your health and well-being, now and in the future. But sometimes even knowing about all of the dangers isn't always enough to make you quit. Fortunately, if you're serious about trying, you have lots of help:
Visit the breastcancer.org Lower Your Risk section to learn more about how you can kick the smoking habit for good.
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