A very small study suggests that nerve blocking may ease hot flashes and night sweats in postmenopausal women being treated for hormone-receptor-positive breast cancer. These results were presented at the 2009 San Antonio Breast Cancer Symposium.
Hot flashes, night sweats, and difficulty sleeping can be common side effect of hormonal therapy medicines used to reduce the risk of hormone-receptor-positive breast cancer coming back (recurrence). These side effects can severely affect the quality of life of some women being treated for breast cancer.
The stellate ganglion is a group of nerves on either side of the base of the neck. These nerves affect many sensations and functions, including sweating and blushing. Injecting the stellate nerves with a long-acting numbing medicine (similar to what's used during dental procedures) can ease certain conditions, including extreme facial sweating. So doctors wondered if a stellate ganglion block might ease hot flashes.
In this study, 24 postmenopausal women being treated for hormone-receptor-positive breast cancer were having troubling hot flashes, night sweats, and difficulty sleeping. Most of the women were taking either tamoxifen or an aromatase inhibitor. Nearly all of the women also were taking one or both of two prescription medicines -- Catapres (chemical name: clonidine) and Effexor (chemical name: venlafaxine) -- to ease these symptoms.
All of the women had a stellate ganglion block injection on one or both sides of their necks using a long-lasting numbing medicine (chirocaine). The women got one or more injections and the procedure was done in a doctor's office. While 11 women had one injection, some women had a second or third injection if they didn't get any relief after the first one. Ten women got a second injection, which was done 2 months after the first. Three women got a third injection that was done 1 month after the second. Most of the women (14) were followed for about 6 months and the rest of the women were followed for shorter periods of time.
The women kept a hot flash scoring diary that recorded the frequency and intensity of the hot flashes. Sleep quality was analyzed with a tool called the Pittsburgh Sleep Quality Index.
After the nerve block:
- 17 of the 24 women had improved hot flash scores and the improvement lasted throughout the follow-up period for 12 women; lasting improvement was more likely in women who had more than one injection
- 14 of the 24 women had better sleep quality and the improvement lasted throughout the follow-up period for 12 women
- 6 of the 24 women had no improvement in either hot flashes or sleep quality after the nerve block injections
Because the stellate nerves control some eye movements, people who have a stellate ganglion block temporarily may have Horner's sign or Horner's syndrome. The symptoms of Horner's sign include drooping eyelids, narrowed pupils, and loss of the ability to sweat on the side of the face where the nerve block was given. Some of the women did have Horner's sign right after they got the nerve block, but the symptoms went away quickly. None of the women had any other side effects from the nerve block.
The results of this very small study are promising and other very small studies have shown similar, promising results. Still, it's important to remember that these studies are VERY preliminary. Stellate ganglion nerve blocks shouldn't be used routinely until more is known about the benefits and risks of the procedure. The researchers who did these small studies wanted to know if stellate ganglion block would help at all. Based on these positive results, stellate ganglion block will be studied in larger groups of women. Researchers also are looking at using different methods to block the stellate nerves.
If you're a postmenopausal woman having troublesome hot flashes and sleep disturbances because of breast cancer treatment, you might want to talk to your doctor about this study. Until more research is done, your doctor probably won't recommend a stellate ganglion block. Still, there are other techniques you can use to ease hot flashes. Visit the Breastcancer.org All About Hot Flashes page to learn more about hot flashes, how to avoid them, and how to manage them.