Teen smokers face 70%
higher breast-cancer risk

October 4, 2002

By OLIVER MOORE
Globe and Mail Update

On top of its many already well-publicized dangers, adolescent smoking has now been linked by Canadian researchers to a massively increased risk of breast cancer.

Writing in this week's issue of the medical journal Lancet, British Columbia doctor Pierre Band suggests that the immature breast tissue of teenage girls is especially susceptible to damage from the toxins present in cigarette smoke.

The news comes during the internationally recognized Breast Cancer Awareness month and was released only one day after publication of a massive study which suggested that breast self-examination does not reduce cancer mortality rates.

Writing in Lancet, Dr. Band notes that previous studies had shown that the increased sensitivity of female breasts between menarche (first menstruation) and first full-term pregnancy leaves women susceptible to environmental carcinogens.

"Human breast tissue is most sensitive to environmental carcinogens during periods of rapid cell proliferation when differentiation is incomplete," Dr. Band explains. "The raised risk of breast cancer associated with cigarette smoking is probably related to exposure to potent carcinogens contained in tobacco smoke."

Researchers sent questionnaires to 2,933 British Columbia women under the age of 75, roughly half of them diagnosed with breast cancer and the remainder as a control group. Six hundred and fifty-eight responded, 318 premenopausal and 340 postmenopausal.

Cross-referencing smoking patterns with cancer rates, researchers found a huge difference between those who had smoked in adolescence and those who had not.

"British Columbian women have a premenopausal breast cancer risk of one in 55. An increased risk of 70 per cent would lead to an additional 1,000 premenopausal breast cancer cases out of 100,000 teenage smokers," Dr. Band writes.

"[The results] add epidemiological evidence to experimental studies, relating susceptibility to carcinogenesis to the biology of breast development," he added.

Dr. Band urged governments to take heed of his study and design anti-smoking campaigns to emphasize the importance of smoking prevention, particularly among the young.

reprinted with permission