Unopposed oestrogen and survival of breast cancer

It has been suggested that survival of breast cancer patients may be affected by their hormonal milieu. the level of circulating oestrogen in a womanʹs body changes with the phase of menstrual cycle, the amount of body fat and her menopausal status. We examined whether these factors affect survival from breast cancer. Meta-analysis of relevant literature for age (reflecting menopausal status; 22 studies), timing of surgery during the menstrual cycle in premenopausal women (28 studies) and body weight in postmenopausal women (18 studies), was carried out to determine the effect of unopposed oestrogen at the time of surgery on survival in breast cancer. The meta-analyses revealed a significantly better survival in premenopausal vs postmenopausal patients (OR 0.76, CI 0.74–0.78, 2P < 0.0000001), in patients who were operated in the luteal vs follicular phase of the menstrual cycle (OR 0.87, CI 0.79–0.97, 2P < 0.02), and in postmenopausal women who were not obese vs obese (OR 0.64, CI 0.59–0.70 2P < 0.0000001). These data indicate that unopposed oestrogen at the time of surgery may have a deleterious effect on survival in women of all ages. It prompts future research into changing the hormonal milieu at the time of surgery as a means of improving survival.