Long-Term Smoking Increases Risk of Cancer in Women Already at High Risk of Breast Cancer

Long-term smoking raises the risk of invasive lung and colon cancer in women who are already at increased risk of breast cancer due to family history or other factors, according to a new study. Smoking also raises the risk of breast cancer for these women to levels even higher than for nonsmoking women with a family history of breast cancer, the study found.

HealthDay reports that researchers studied 13,388 women who were at increased risk of breast cancer because of factors including a family history of the disease or their age. The study found that compared with women who had never smoked, those who smoked for at least 35 years were 60 percent more likely to develop invasive breast cancer. Women who smoked between 15 and 35 years had a 34 percent higher risk of invasive breast cancer compared with those who never smoked.

Women who smoked for at least 35 years were also more than four times as likely to develop colon cancer compared with women who never smoked. For women who smoked for between 15 and 35 years, the researchers found a 7 percent increased risk of colon cancer.

The study also found that women who smoked more than one pack of cigarettes a day for more than 35 years were 30 times more likely to develop lung cancer compared with women who never smoked.

The findings were presented at the American Society of Clinical Oncology Annual Meeting.