In a recent post, I discussed chronomodulated chemotherapy, which is the infusion of drugs at optimal times to improve treatment sensitivity and tolerance. A broader definition would include the synchronizing of the administration of chemotherapy drugs to a patient’s individual internal clock, or biological rhythm. Research suggests that doing so can maximize the effectiveness of the drugs, while minimizing their toxicity. This can not only help manage treatment side effects, but improve response and survival as well. It turns out there are other "body cycles" that can impact the effectiveness of cancer therapy. For example, the time of the month, based on one's menstrual cycle, that a woman schedules surgery for breast cancer can impact her long term outcome.
There is a growing body of research – which my clinical experience supports – that demonstrates that the optimal timing of breast cancer surgery in relationship to the phase of the menstrual cycle may reduce the risk of recurrence a woman faces. It turns out that premenopausal women who undergo a surgery – either a lumpectomy or a mastectomy – during the second half of their menstrual cycle (counting the first day of bleeding as day 1, this is typically days 15 through 28), appear to have a lower risk of recurrence and better survival than women who have surgery during the first half of their cycle. Taken together, studies from major cancer centers show a 15% increase in ten-year survival for women operated on during the second half of their cycle, or post-ovulatory. This makes biological sense. During the first half of the cycle there is an increase in levels of hormones and growth factors that might speed the progression of breast cancer. These can be present at high levels in the bloodstream. Surgery to remove the tumor can release malignant cells into the blood, where the hormones may spur them to proliferate. In contrast, these growth- promoting hormones are at lower levels during the second half of the monthly cycle. As an added benefit, new studies show that biochemicals that promote angiogenesis, the growth of blood vessels that feed tumors, are also at higher levels during the first half of the cycle, while ones that discourage angiogenesis are higher during the second half.
Here’s some additional data:
In a study at the University of California at San Diego, researchers followed a diverse group of 400 premenopausal women who underwent surgery for breast cancer at four different hospitals for three years. They found that women who were operated on in the early part of their menstrual cycle had a greater chance of recurrence and an increased risk of death, than women operated on late in their cycle, while controlling for stage of breast cancer, type of surgery, family history, and age.
Whether you should request surgery during the second half of your cycle hinges on several factors. If your situation is urgent, if the tumor is large or growing at an accelerated pace, it is important to review this research with your doctor. Otherwise, and if scheduling surgery during the second half of the cycle means waiting only a few days longer, I advise patients that there is likely a benefit to waiting. Specifically, if the tumor is small (less than one centimeter) and shows no signs of growing rapidly (a grade 1 tumor with low Ki- 67, low S- phase fraction, or low number of necrotic cells), it may be advantageous to schedule surgery during the second half of your cycle.
One warning: Over the years, I have witnessed some of my patients that were scolded or dismissed by their surgeons when they requested that the surgery be scheduled around the optimal timing of their menstrual cycle. While there are some surgeons who don't buy into this, there is no legitimate downside. So if this is an important factor to you in scheduling your surgery, don't accept anything less from your surgeon.
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