Hot flushes and night sweats (HF/NS) affect 65-85% of breast cancer survivors, with 60% rating them as severe . They are associated with sleep problems, reduced health-related quality of life [2–4] and are more chronic in this population . Chemotherapy and endocrine treatments such as tamoxifen can induce or exacerbate menopausal symptoms and those taking hormone therapy (HT) are generally advised to stop treatment. HT is an effective treatment, but there is uncertainty associated with its safety. Results of prospective trials [6, 7] highlight the association between HT and breast cancer and cardiovascular risks. Therefore a clear need exists for safe and effective non-hormonal targeted therapies that are well tolerated .
The exact aetiology of HF/NS is unknown, but they appear to be associated with the rate of change of plasma oestrogen, which influences the thermoregulatory system via the hypothalamus . Alterations in oestrogen levels and neurotransmitters (norepinephrine and serotonin) have been implicated in the pathogenesis of HF/NS . Freedman  proposed that there is a narrowed thermoneutral zone (temperature range in which thermoregulation is not triggered) in women who have HF/NS resulting in flushes being triggered by small elevations in core body temperature, caused by changes in ambient temperature or triggers, such as anxiety or stimulants. There is some evidence that the thermoneutral zone is narrowed by elevated brain norepinephrine [10, 11], and that stressors increase incidence of hot flushes . Anxiety  and cognitions (negative thoughts associated with embarrassment, social anxiety, feeling out of control and unable to cope) are associated with reports of more frequent and problematic HF/NS [14, 15], and lifestyle, mood and cognitive and behavioural reactions are likely to influence perception of symptoms . Although the aetiology of hot flushes and night sweats is likely to be the same, their impacts on women are very different. Hot flushes during the day tend to be associated with problems of social anxiety, discomfort and managing day to day activities, whereas night sweats occurring during the night tend to be associated with sleep disruption and associated problems.
Evaluating treatment efficacy depends on valid and reliable measures of HF/NS. The most commonly used measures of HF/NS are women's own self-reports. These include diaries, in which women note the time when a hot flush occurs and usually a severity rating (e.g. mild, moderate or severe). Electronic event markers can also provide a convenient method of registering a perceived hot flush. Sternal skin conductance (SSC) is considered to be the most valid physiological index of HF/NS . A hot flush is marked by a sudden increase in skin conductivity, due to a sweat response, which tails off as sweating decreases (a 'swishy tail'). This pattern is in contrast with a 'saw-tooth' fluctuation in sweating which occurs in typical thermoregulatory control. SSC does not, however, correlate well with subjective measures of severity or problem ratings, and hot flushes defined by SSC and self-reported hot flushes are not always concordant . Reasons for discordance are not well understood, but use of both measures can increase understanding of the impacts of interventions . For example, self-report but not physiological measures (SSC) have shown placebo effects , but physiological measures are less predictive of problem ratings and help seeking than self-reports. For these reasons SSC should be used together with self-report measures (frequency and the extent to which they are problematic) . SSC has not yet been used to evaluate treatments in the UK. 24 hour SSC monitoring has been piloted and has been acceptable to women [21, 22].
Non-hormonal treatments for menopausal symptoms in breast cancer patients
Non-hormonal treatments for HF/NS tend to be preferred but the efficacy and acceptability of treatments limit their use. Following a systematic review of non-hormonal medicines for HF/NS, Nelson, Vesco, Haney and others  concluded that SSRIs or SNRIs, clonidine and gabapentin trials provide evidence for efficacy but that adverse effects might restrict use for some women. Carpenter, Storniolo, Johns et al  reported modest reductions (22%) in HF/NS with Venlafaxine (37.5 mgs) but most patients discontinued treatment at 12 months follow up. These conclusions support those of a position statement by the North American Menopause Society . Furthermore, possible negative interactions between some SSRIs and the effects of tamoxifen may limit prescribing options for women who have had breast cancer .
Non-medical treatments are popular, including acupuncture, yoga, exercise, and cognitive behavioural therapy. Studies of acupuncture often report significant reductions in HF/NS following treatment, although few studies report between group effects when compared to sham, superficial or placebo acupuncture . A recent meta-analysis  of 4 RCTs of acupuncture for HF/NS in women who have had breast cancer found one RCT that reported significantly fewer HF/NS following acupuncture compared to sham acupuncture . In well women one study out of six reviewed  reported a reduction in severity following acupuncture compared to placebo . Both studies involved a comparatively large number of acupuncture sessions, suggesting that it may be effective over and above placebo effects if delivered intensively. Furthermore it would also be worth investigating the reasons for these consistent placebo improvements, and whether they are enduring.
Regular exercise has been associated with fewer HF/NS in cross-sectional studies, but interventions to reduce symptoms using exercise have been less successful . In a systematic review of seven studies, about half reported significant within-group improvements following exercise, but only two reported improvements in HF/NS compared to a no treatment control (one was not powered to find a significant difference ). Although there were no studies focusing on breast cancer patients, an RCT of exercise for breast cancer patients with treatment induced HF/NS is due to publish findings in 2011 . Theoretically, yoga may be more effective than exercise; as well as being low intensity exercise, yoga is used as a relaxation technique, which may also reduce HF/NS . A systematic review revealed a reduction in reported HF/NS in 4 out of 7 studies , however most RCTs did not find an effect. The exception was an RCT of an intensive yoga programme (60 minutes a day, 5 days a week for 8 weeks) . The only study to measure frequency of physiological HF/NS as well as self-reported HF/NS found no reduction in sternal skin conductance or diary reported hot flushes and night sweats following yoga . There is growing evidence that relaxation therapy and paced respiration can alleviate HF/NS in well women [38–41]. In two preliminary studies with breast cancer patients relaxation significantly reduced HF/NS after 12 sessions  but not after one session . A treatment package including behavioural (relaxation and counselling) and pharmacological interventions for breast cancer patients has been evaluated in the US with positive results .
A CBT intervention for HF/NS, which includes relaxation and paced respiration, has been developed in the UK by Hunter and colleagues [45–47]. This four-session CBT intervention was shown to be effective in an exploratory patient preference trial of well women (around 40% reduction of HF frequency and problem rating) ; a finding replicated by Keefer and Blanchard  using 8 sessions of CBT. Women who have had breast cancer tend to experience more frequent and problematic menopausal symptoms than well women going through the natural menopause . In a study of 113 women, who had completed active treatment for breast cancer within the past 5 years, 80% reported HF and 72% NS, a significantly higher prevalence than found in well postmenopausal women . Treatment preferences were explored and preferences were expressed for CBT (63%), complementary therapies (46%), antidepressant treatment (25%) and HT (26%). 53% expressed interest in group and/or individual CBT sessions .
Based on earlier work, an exploratory trial of a six-session Group CBT intervention was evaluated in a pre-post study of 24 breast cancer patients . The weekly problem rating reduced on average from 5.9 (SD = 2.1) to 3.4 (SD = 1.8) at post-treatment and 2.8 (SD = 1.8) at follow-up (10 point scale); frequency of HF/NS per week reduced from 68.2 (SD = 28.7) to 46.7 (SD = 30.2) at post-treatment and to 36.9 (SD = 32.5) at 3 months follow up; a significant reduction in HF problem rating and frequency. Feedback from the women, elicited during and at the end of the groups, was very positive . Relaxation/breathing and cognitive strategies used at the onset of HF/NS, as well as group support to make behavioural changes, were seen as most useful. The majority (88%) completed the 3 month follow-up assessment, suggesting good adherence to the study. These results suggest that CBT may be effective in reducing HF/NS and their impacts in breast cancer patients. However, a randomised controlled trial is needed. Furthermore, most studies of the efficacy of CBT used self-reported improvements in HF/NS, thus investigation into the impacts on physiological symptoms is warranted.
This present study aims to evaluate the effectiveness of Group CBT to alleviate HF/NS in women who have had treatment for breast cancer, comparing Group CBT and usual care in a randomised controlled trial, with both physiological and self-reported measures of HF/NS and a 6-month post-randomisation follow-up. We hypothesize that Group CBT will be more effective than usual care in reducing HF/NS problem rating and frequency. Secondary analyses will examine the effects of Group CBT on hypothesised mediating variables, including mood, quality of life, beliefs and behaviours, optimism and somatisation. If effective, the treatment can be promoted by publication of the treatment manual and by training and supervising health professionals in the application of the treatment.
The trial tests four main hypotheses:
There will be a significant reduction in problem rating of HF/NS following Group CBT compared to usual care.
There will be a significant reduction in frequency of self-reported and SSC-defined HF/NS following Group CBT compared to usual care.
Changes in problem rating and frequency of HF/NS following Group CBT will be maintained at six months post-randomisation.
There will be significant improvements in mood, beliefs and behaviours about HF/NS and quality of life following Group CBT compared to usual care.