The US researchers reported on Thursday that blocking parts of the nervous system that regulate body temperature can reduce hot flashes and improve sleep in survivors of breast cancer.

The study published in the online issue of the Lancet Oncology articulated that the average number of hot flashes per week fell from about 80 to just 8 with the experimental nerve blocker therapy. The study found that very severe hot flashes were almost totally abolished and there was a marked drop in nighttime awakenings.

According to researchers, Hot flashes and sleep dysfunction are common in breast cancer survivors, particularly those who use anti-estrogen agents like tamoxifen. Conventional treatments, such as hormone therapy or herbal remedies, have proven either ineffective or have been linked to important side effects.

Dr. Eugene G. Lipov, from Advanced Pain Centers in Hoffman Estates, Illinois, and colleagues found that blocking the function of "stellate cells" -- star-shaped nerve cell bodies found at the base of the neck -- has been used to treat various conditions for more than 60 years. They theorized that this treatment may provide a safe and effective alternative to current therapies used to treat hot flashes and sleep dysfunction in breast cancer survivors.

The new study involved 13 survivors of breast cancer with severe hot flashes and night awakenings who received targeted delivery of a stellate cell blocker. Women were given one block, but during the course of the study they were permitted to have another if they thought that the beneficial effects were waning. Five women had one block and eight had two blocks. Symptoms were assessed one week before treatment and then every week after treatment for 12 weeks.

The study found that with treatment, the average number of hot flashes per week fell from 80 to 8, as mentioned, and severe hot flashes virtually disappeared. Night awakenings dropped from 19.5 per week prior to treatment to just 1.4 per week.

The researchers affirmed, the findings of this study suggest that this type of nerve blockade can provide survivors of breast cancer with relief from hot flashes and sleep dysfunction "with few or no side-effects," the investigators conclude. They said, "Long-term relief of symptoms has the potential to improve overall quality of life and increase compliance with anti-estrogen medications for breast cancer.”