A study in the June 25th issue of the Journal of the American Medical Association offers additional warning about the use of combined hormone therapy (CHT) in postmenopausal women. The first study from the Women's Health Initiative (WHI) shows that not only is the incidence of breast cancer increased with CHT, but that it is diagnosed at a more advanced stage because CHT decreases mammographic sensitivity to the tumours. For years, women have told that hormone therapy would help reduce the risks of cardiovascular disease and osteoporosis while enhancing quality of life and life expectancy and that the benefits of hormone replacement therapy outweighed the risks. Moreover, while it was admitted that estrogen-progestin hormone therapy raised the risk of breast cancer, we were reassured that the tumours tended to be less likely to kill and that risk was related to long-term use. According to the new research, even after relatively short-term use, tumours diagnosed in women taking CHT were slightly bigger, more advanced and more likely to have spread into nearby lymph nodes as compared to tumours found in women not taking the drugs. Women using estrogen therapy alone had no significant increase in the risk of breast cancer but there was an increased risk of uterine cancer. Overall there was a 24% increase in breast cancer among women on CHT and their tumours were found at a substantially later stage, suggesting a poorer prognosis.

The WHI is a randomized, placebo-controlled trial involving 161,000 women who are part of a number of clinical trials or observational studies involving CHT, estrogen alone, low-fat diet and calcium/vitamin D supplementati. The arm of the trial looking at CHT consisted of 16,608 women aged 50 to 79 with an intact uterus. This arm of the WHI was stopped earlier than planned when interim analysis revealed that overall health risks (including breast cancer) associated with CHT exceeded the benefits. Other health problems relating to use of CHT include cardiovascular diseases and an increased risk for dementia in women over 65. (Chlebowksi RT, Hendrix SL, Langer RD et al. Influence of estrogen plus progestin on breast cancer and mammography in healthy postmenopausal women: the Women's Health Initiative Randomized Trial. JAMA 2003; 289 (24): 3243-53)

A new study has examined the benefits of exercise for women who have survived breast cancer. The research team assigned breast cancer survivors to an exercise group or a control group. The women who exercised regularly not only improved heart and lung health but found that they felt better overall. there was also a 12% improvement in survival. (Courneya KS, Mackey JR, Bell GJ et al. Randomized controlled trial of exercise training in postmenopausal breast cancer survivors: cardiopulmonary and quality of life outcomes. Journal of Clinical Oncology 2003; 21(9): 1660-8)

A large study involving more than 90,000 nurses has found that young women between the ages of 26 and 46 who eat a lot of red meat and high-fat dairy products are at increased risk of developing breast cancer. The women in the high-fat-intake group who obtained about 23% of their total calories from fat (as compared to 12% in the low-fat-intake group) had a 33 % greater risk of being diagnosed with breast cancer. (Cho E, Spiegelman D, Hunter DJ et al. Premenopausal fat intake and risk of breast cancer. Journal of the National Cancer Institute 2003; 96(14): 1079-85.