Canadian researchers have completed a study finding that girls who start smoking in their early teens are two-thirds more likely to develop breast cancer later in life than non-smokers.
Lead researcher, Pierre Band of the British Colombia Cancer Agency in Vancouver collected date from interviews with more than 1,000 adult women in the western Canadian province of British Colombia who had had breast cancer. The data was compared with more than 1,000 women who had not had breast cancer.
The research showed that the risk of breast cancer in later life was almost 70% higher for women who started to smoke within five years of their first menstruation than for non-smokers.
Results of the research suggest that breast tissue is at its most sensitive to tobacco’s carcinogens during puberty when mammary cells are still developing. This has been backed by the study’s findings that post-menopausal women who started smoking after their first pregnancy were not facing such a high risk of developing breast cancer. They also found (among lab animals) that breast tissue is less susceptible to chemical carcinogens after a first full-term pregnancy.
Band said, “our evidence of the detrimental effect of cigarette smoking on the most frequent sex-specific cancer in women should reinforce the importance of smoking prevention, especially in adolescence”.
The research has been published in Saturday’s issue of the British medical weekly, The Lancet.