Hormone replacement therapy for symptoms but not for chemoprevention of chronic diseases.

A little dust has settled since last year's news from the Women's Health Initiative (WHI) randomized trial about the use of combined hormone replacement therapy (HRT) during and after menopause: long-term use may increase a woman's chances of becoming chronically ill (Women's Health Initiative Investigators, 2002). In none of the three age-groups studied (women in their 50s, 60s and 70s) was the presumed cardioprotective effect of HRT confirmed, and in all age groups, the hormone users had more heart attacks, strokes, and blood clots than the control as well as more breast cancer. The placebo arm (women not receiving HRT) had more fractures and more cases of colon cancer than the hormone users, but on balance, the non-users still had fewer serious adverse health effects. The WHI estrogen and progestin arm was prematurely stopped in July 2002 because the overall risks of the intervention outweighed the benefits (Women's Health Initiative Investigators, 2002).

Targeting angiogenesis -- a novel mode in cancer chemoprevention.

Cancer prevention is fast emerging as a discipline with a promising potential. Chemoprevention has its rationale in the multistage process of carcinogenesis which provides an option for development of preventive approaches in the early, premalignant stages, before appearance of clinical symptoms. Evidence is mounting that the angiogenic switch may be an early event in carcinogenesis. Most chemopreventive agents currently under development probably act via multiple mechanisms. The chemopreventives used in clinical trials, such as nonsteroidal anti-inflammatories, tamoxifen and retinoids, have been shown to inhibit angiogenesis, the formation of new vessels from existing vasculature, which may contribute to their protective effect. Development and use, alone or in combination with other agents with other mechanisms of action, of specific antiangiogenic agents is likely to open new possibilities in cancer chemoprevention.