Research presented yesterday at the American Society of Clinical Oncology in Philadelphia overturned the common belief that days 15-32 of the menstrual cycle are best for cancer surgery. The study, among 716 pre-menopausal women, showed that those operated on in the second phase of the cycle were almost twice as likely to experience a recurrence as those operated on on days 1-14.
Almost one-third of women who underwent surgery in the second half of the cycle relapsed, compared with 19 per cent of those operated on in the first two weeks. Day eight was calculated as the optimum time by Professor Mark Norman Levine of the Ontario Cancer Foundation, Hamilton University, and the National Cancer Institute of Canada Clinical Trials Group.
Obstetrician Patricia Braly, of Louisiana State University, told the conference, attended by 14,000 cancer specialists: "In contrast to other studies, this is the first to show that there is an increased risk of breast cancer recurrence if surgery is performed during the latter part of the menstrual cycle."
Swings in hormone levels through a woman's cycle are thought to account for variable success rates in treatments, but the researchers did not advocate major changes in surgery at this time.
A British cancer specialist, Dr Vivien Bramwell-Wesley, at the Regional Cancer Centre in London, Canada, said a trial of about 800 patients randomly allocated for surgery at different stages in the cycle was imperative to settle the debate. "It could be tough to organise because surgeons have strong opinions on when to operate and patients have strong opinions too."Reuse content