Some patients may be better served by getting their drugs late in the afternoon or even at night. Portable infusion pumps may hold the answer. The optimal timing of cancer surgery, particularly breast cancer, has also come under study. Some researchers believe that in premenopausal women, surgical cure of breast cancer is more likely if surgery is performed in the middle of a woman's menstrual cycle in the week or so following ovulation. At the May 1996 International Conference on Breast Diseases in Houston, Umberto Veronesi, M.D., of the European Institute of Oncology in Milan, Italy, presented 20 years of follow-up data on nearly 1,200 premenopausal women who underwent surgery for breast cancer.
Many experts believe that any improved outcome is hormone-related.
In the first half of the menstrual cycle, estrogen levels are high, and progesterone is not produced. In the second half, progesterone rises and estrogen falls. It is believed that progesterone may inhibit the production of some enzymes that help cancer spread. However, some experts dispute the need to time breast cancer surgery according to the menstrual cycle. G.M. Clark, M.D., of the University of Texas Health Science Center at San Antonio, reported at the conference that retrospective analyses from at least 23 studies involving more than 6,000 patients failed to find any significant impact of the menstrual cycle division on breast cancer prognosis.