The results of a large Swedish study is published in the February issue of journal Breast Cancer Research. The research team from the Karolinska Institutet in Stockholm and the Genome Institute of Singapore carried out a population-based case-control study of women recently diagnosed with invasive breast cancer. They selected 1,888 women with ductal breast cancer, 308 women with lobular cancer and 93 women with tubular breast cancer. All women were matched for age with 3,065 women randomly selected from the population, acting as controls. Both patients and controls were asked to fill in a questionnaire about their medical history, health status and use of menopausal hormone therapy.
The results show that women who used medium potency estrogen-progestin combination therapy had a higher relative risk of developing lobular or tubular breast cancer than of developing ductal cancer, compared with women who did not use hormone therapy. The risk of developing any of the cancers was higher for women who had used the therapy for more than five years. For these women, the relative risk of developing tubular cancer or lobular cancer was more than twice the relative risk of developing ductal cancer.
Other factors, such as the number of births, age at menopause or body mass index, were found to be associated with a similar risk of developing the three subtypes of breast cancer.
“Menopausal hormone therapy and other breast cancer risk factors in relation to the risk of different histological types of breast cancer: a case-control study”
Lena U Rosenberg, Cecilia Magnusson, Emma Lindstrom, Sara Wedren, Per Hall and Paul W Dickman
Breast Cancer Research, February 2006.