Smoking Increases Risk of Breast Cancer in Younger Women

Smoking Increases Risk of Breast Cancer in Younger Women

By Bryan Le 02/25/14

Researchers found that women who are long-term heavy smokers were 60 percent more likely to develop a common form of breast cancer.

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While a link has already been established between smoking and breast cancer, researchers have found new evidence that cigarettes can cause breast cancer in young smokers.

Women between ages 20 and 44 who smoked a pack a day for at least 10 years were found to be 60 percent more likely to develop a common form of breast cancer known as estrogen-receptor positive breast cancer. The researchers noted, however, that smoking does not seem to affect the chances of developing a less common, but more aggressive form of breast cancer known as triple-negative beast cancer.

"I think that there is growing evidence that breast cancer is another health hazard associated with smoking," said lead researcher Dr. Christopher Li.

Li and his team examined records of young women diagnosed with breast cancer between 2004 and 2010 in the Greater Seattle area and compared them against cancer-free women. Young women who smoked were 30 percent more likely to develop any kind of breast cancer, and those who had smoked for at least 15 years were 50 percent more likely to develop estrogen-receptor positive breast cancer. A pack-a-day habit maintained for at least 10 years boosted the risk of estrogen-receptor positive breast cancer to 60 percent.

Li's team was not sure why smoking contributes to a higher risk of estrogen-receptor positive breast cancer, but they theorized that that substances contained in cigarettes might be acting like estrogen.

"There are so many different chemicals in cigarette smoke that can have so many kinds of effects," Li said.

But results from other studies examining the link between smoking and breast cancer have yielded conflicting results.

"We know smoking is bad for you and the earlier you smoke and the more often you smoke the worse off you're going to be in terms of many outcomes," said Geoffrey Kabat, a researcher not involved with Li's study. "But the role of smoking in breast cancer is not clear. There may be something going on and it may be a modest effect in some subgroups."