Effects of stellate-ganglion block on hot flushes and night awakenings in survivors of breast cancer: a pilot study

Menopausal hot flushes and night sweats: where are we now?

OBJECTIVE

An overview of the current knowledge on the etiology and treatment of vasomotor symptoms in postmenopausal women.

MATERIALS AND METHODS

Acknowledged experts in the field contributed a brief assessment of their areas of interest which were combined and edited into the final manuscript.

RESULTS

Women around the world experience vasomotor symptoms as they enter and complete the menopause transition. Vasomotor symptoms, specifically hot flushes, are caused by a narrowing of the thermoneutral zone in the brain. This effect, although related to estrogen withdrawal, is most likely related to changes in central nervous system neurotransmitters. Peripheral vascular reactivity is also altered in symptomatic women. Estrogen replacement therapy is the most effective treatment for hot flushes. Of the other interventions investigated, selective serotonin and selective norepinephrine reuptake inhibitors and gabapentin show efficacy greater than placebo. Objective monitoring of hot flushes indicates a robust improvement with hormone replacement therapy but little to no change with placebo. These data suggest that the subjective assessment of responses to therapy for vasomotor symptom results in inaccurate data. Hot flushes have recently been associated with increased cardiovascular risks and a lower incidence of breast cancer, but these data require confirmation.

CONCLUSIONS

Vasomotor symptoms are experienced by women of all ethnic groups. They are caused by changes in the central nervous system associated with estrogen withdrawal and are best treated with estrogen replacement therapy. Objective monitoring of hot flushes indicates that placebo has little to no effect on their improvement. Subjective assessments of hot flushes in clinical trials may be inaccurate based on objective measurement of the frequency of hot flushes. Based on preliminary reports, women experiencing hot flushes have an increased risk of cardiovascular disease and a reduced incidence of breast cancer.

Pilot evaluation of a stellate ganglion block for the treatment of hot flashes

PURPOSE

Hot flashes are a significant problem in breast cancer patients, especially because the most effective therapy, estrogen, is often contraindicated. Based on recent pilot data from a single group supporting the use of a stellate ganglion block for the treatment of hot flashes, the present pilot trial was done to further evaluate the hypothesis that a stellate ganglion block may be a safe and effective therapy for hot flashes.

METHODS

In women with breast cancer who had hot flashes, a stellate ganglion block was performed after 1 week of baseline hot flash data collection. The main efficacy measures were the changes from baseline in hot flash frequency and hot flash score during the 6th week.

RESULTS

Ten patients were enrolled between 4/23/2009 and 7/10/2009; eight patients were evaluable. After the stellate ganglion block, the mean hot flash frequency and score decreased from baseline values by over 60% during some of the post-treatment weeks. The mean hot flash frequency and score at week 6 decreased from baseline values by 44% and 45%, respectively. There were no significant adverse events clearly attributed to the stellate ganglion blocks.

CONCLUSIONS

The results of this pilot trial support that stellate ganglion blocks may be a helpful therapy for hot flashes. A prospective placebo-controlled clinical trial should be done to more definitively determine this contention.

Hot flushes: are there effective alternatives to estrogen?

Hot flushes are the most common indication for the prescription of hormone replacement therapy (HRT) since it is effective in over 80% of cases. In 1995, 37% of American women took HRT, principally for this purpose. However, over the last five years, publications such as those from the Women's Health Initiative (WHI) have caused concern among women since they perceive that the risks outweigh the benefits. Following this publication, half of the women taking HRT in the UK, USA and New Zealand discontinued HRT. With the discontinuation of estrogen many women re-developed hot flushes; however only a small number (18%) of women report restarting hormone therapy. The majority of these (76%) for the recurrence of severe hot flushes or night sweats. Alternatives are available, but limited knowledge on aetiology and mechanisms of hot flushing represents a major obstacle for the development of new, targeted, non-hormonal treatments, and no current alternatives are as effective as estrogen.

Management of menopause-associated vasomotor symptoms: Current treatment options, challenges and future directions

Hot flashes are one of the most common and distressing symptoms associated with menopause, occurring in more than 75% of postmenopausal women. They are especially problematic in breast cancer patients since some breast cancer therapies can induce hot flashes. For mild hot flashes, it is proposed that behavioral modifications are the first step in management. Hormonal therapies, including estrogens and progestogens, are the most well known effective agents in relieving hot flashes; however, the safety of these agents is controversial. There is an increasing amount of literature on nonhormonal agents for the treatment of hot flashes. The most promising data regard newer antidepressant agents such as venlafaxine, which reduces hot flashes by about 60%. Gabapentin is another nonhormonal agent that is effective in reducing hot flashes. While many complimentary therapies, including phytoestrogens, black cohosh, and dehydroepiandrosterone, have been explored for the treatment of hot flashes; none can be recommended at this time. Furthermore, there is a lack of strong evidence to support exercise, yoga, or relaxation for the treatment of hot flashes. Paced respirations and hypnosis appear to be promising enough to warrant further investigation. Another promising nonpharmacological therapy, currently under investigation, involves a stellate ganglion block.

A unifying theory linking the prolonged efficacy of the stellate ganglion block for the treatment of chronic regional pain syndrome (CRPS), hot flashes, and posttraumatic stress disorder (PTSD)

The mechanism of action of the stellate ganglion block (SGB) is still uncertain; however it has been used successfully in treatment of chronic regional pain syndrome (CRPS) for many years. Our new insights in to the mechanism of action of the stellate ganglion block were first reported in 2007 in our publication detailing the control of hot flashes with the use of stellate ganglion blockade. We have demonstrated very significant results in the treatment of hot flashes and our most recent application of this block has been for the treatment of posttraumatic stress disorder (PTSD). Stellate ganglion has been demonstrated to have second and third order neurons connections with the central nervous system nuclei that modulate body temperature, neuropathic pain, the manifestations of PTSD, and many other areas. We believe that the commonality between the CRPS, HF and PTSD is the trigger of increased nerve growth factor (NGF) leading to the increase in brain norepinephrine (NR), which in turn is affected by the SGB leading to a prolonged reduction of NGF and eventually a decrease in NR. This, in turn, leads to a reduction or elimination of many of the symptoms of CRPS, Hot flashes, and PTSD.

Symptom management in premenopausal patients with breast cancer

Women with breast cancer have many adverse symptoms, of which some are specific to premenopausal patients. Management of these common symptoms include non-hormonal drugs, such as antidepressants and antiseizure compounds to alleviate hot flushes. Non-oestrogenic vaginal lubricants seem to moderately decrease occurrence of vaginal dryness and dyspareunia. Transdermal testosterone alone has not been shown to improve libido in these women. Options for fertility preservation include cryopreservation of embryos or oocytes before chemotherapy. Exercise is the one evidenced-based intervention shown to positively affect cancer-related fatigue. However, effective prevention and treatments for peripheral neuropathy and paclitaxel acute pain syndrome remain elusive. Weight-bearing exercise helps to maintain bone strength with adequate intake of calcium and vitamin D. Use of bisphosphonates in women taking aromatase inhibitors (combined with ovarian suppression in premenopausal women) to prevent bone fractures has not been substantiated, although it should be considered in women with osteoporosis. No specific drug has been shown to prevent radiation-induced dermatitis alone. Although some effective treatments can counteract symptoms related to cancer or treatments, research is needed to expand evidence-based care in premenopausal survivors of breast cancer.