NEW YORK--There is sufficient evidence that the timing of breast cancer surgery affects outcome to warrant further inquiry, William J. Hrushesky, MD, said at the 14th Chemotherapy Foundation Symposium.
It is known that tumor growth rates wax and wane during the female menstrual cycle, but many questions remain that can be answered only by rigorously designed studies, said Dr. Hrushesky, senior attending oncologist, Stratton VA Medical Center, and professor of medicine, Albany Medical College.
In his research in both mice and women, Dr. Hrushesky has found that cellular immune function and/or host resistance to cancer growth and spread vary with the reproductive cycle stage. Tumor growth rate is slowest during the early luteal stage, which typically occurs in the first quarter of the cycle after ovulation, a time when the immune response is most robust. It is this stage that appears to be optimal for resection, he said.
"In our own initial clinical series, women resected during the middle of the menstrual cycle proved to have a fourfold better chance of surviving 10 years than those whose breast cancers were resected during or nearer to menses," he said. Ten other retrospective studies have confirmed this finding, and multivariate analyses demonstrate that timing is an independent predictor of both breast cancer recurrence and death, he added.
Does that mean that all breast cancer surgery should be scheduled for the early luteal phase? Not at this time, Dr. Hrushesky said. "Many meaningful uncertainties remain, and only rigorous study can answer them. We need to clarify the impact of resection timing and the size of the window of opportunity--when it opens and closes."
He added that we further need to understand the underlying biology "because a full understanding of the mechanisms may lead to neoadjuvant hormonal strategies to enhance the control of this and other cancers"