Our findings suggest that CBT is safe, acceptable, and effective in helping women to manage hot flushes and night sweats after breast cancer treatment, with additional benefits to mood, sleep, and some aspects of quality of life. After group CBT, women reported less problematic HFNS than did those receiving usual care, and these improvements were maintained at both the 9-week and 26-week follow-up. Although the pre-specified endpoint of a between-group difference of 2 points on the problem-rating scale was not met, there was a statistically significant improvement in the CBT group, and a large proportion of women (78%) who had received CBT achieved a reduction of 2 points compared with the usual care group (33%) at 26 weeks. However, we recorded no significant difference in the frequency of HFNS between the two groups at either 9 weeks or 26 weeks. Similarly, we recorded no significant differences between groups in 24 h rate of HFNS after the treatment phase, either physiologically (SSC) defined or participant recorded (event monitor). Nevertheless, the effects of CBT on HFNS problem rating were substantial and robust. Most women participating in group CBT reported reductions in problem rating that are regarded as clinically important, and there were sustained significant differences in problem rating between CBT and usual care. These differences were not unduly affected by outliers or other influential points (ie, the average group changes were significant), and the sample contained more precise standard deviations than we expected.
Additionally, group CBT provided sustained benefits to depressed mood and sleep and some improvements in dimensions of quality of life. At baseline, on average, participants had higher scores for sleep problems, somatic symptoms, and memory and concentration (WHQ) compared with norms for healthy women ( and data not shown).27
According the the SF-36 scale, they had lower scores (lower quality of life) than did healthy women, especially for physical role functioning, general health, vitality, and bodily pain. The significant improvements in mood and sleep, as well as memory and concentration, after CBT are clinically important because difficulties with mood sleep and cognitive functions are commonly reported by patients with breast cancer, particularly by those with HFNS.30
Moreover, the improvement in social functioning after CBT is relevant because women report finding hot flushes especially difficult to deal with at work and in other social situations.18
Although randomised controlled trials of non-hormonal drugs for HFNS have shown moderate reductions in HFNS frequency, they have recorded little evidence of improved quality of life.9
Similarly, some studies show only weak relations between frequency of HFNS and quality of life.21,22
The results of our study are very similar to the preliminary findings of a parallel trial of CBT for HFNS in a sample of healthy women (MENOS2).31
This consistent pattern of results suggests that the CBT might work by affecting symptom perception and cognitive appraisal of HFNS and possibly mood, rather than physiological mechanisms of HFNS, such as temperature regulation or the thermoneutral zone in the hypothalamus.19
Further analyses of moderators and mediators of HFNS are planned to clarify this issue through identification of the underlying causal pathways to improvement on the hot flush problem rating scale.20
For example, changes in sleep after treatment might partly mediate the improvements in mood and quality of life. We postulate that hot-flush beliefs and behaviours, as well as mood and sleep, will act as potential mediators. For the moderator analysis, baseline clinical and demographical characteristics, such as anxiety and depression, will be considered alongside factors such as drug use and health behaviours. Further studies should examine particular components of the intervention to test these analyses experimentally.
We postulated that CBT would reduce HFNS frequency to a greater extent than would usual care, especially because paced breathing has been shown to reduce HFNS frequency measured both physiologically and subjectively.32
Women receiving CBT reported practising paced breathing daily. Paced breathing, once learnt, is practised for 2–5 min throughout the day and at the onset of a hot flush, so an average of 29 times per week is a realistic rate at which to practise. However, participants in both groups reported improvements in HFNS frequency. Women in the usual care group did receive psychoeducation, advice (which included paced breathing), and nursing support, which could have led to reductions in the usual care group, although we did not record paced breathing or other techniques done by these women. CBT treatment effects could have been attributable to the placebo effect of additional attention in the group CBT. However, we controlled for usual care and assessment effects and we should gain some insight into the placebo effects of usual care through the planned mediator and moderator analysis.20
Further research could compare different types of control conditions with differing levels of information, advice, and support. The group CBT programme should be generalisable to other breast cancer settings because it is delivered in a hospital setting, is done by use of easily transferable guidelines (the treatment manual), and adherence to the guidelines was high. Drop-out rates were low, and the preliminary results of qualitative interviews done at the end of the trial suggest that the CBT was highly acceptable. The cost of delivering the treatment needs to be assessed, with a need for comparison with non-hormonal drugs. The most cost-effective method of delivering the group CBT would probably be to include it as part of survivorship support programme, delivered by trained and supervised breast-care nurses.
To date, the best available treatments have been non-hormonal drugs including SSRI and SNRIs, clonidine, and gabapentin.9
These treatments have produced moderate reductions in HFNS frequency (averaging 37% across trials9
), but have had little effect on quality-of-life measures. By contrast our findings suggest that both CBT and usual care resulted in a 38% reduction in frequency, and compared with the usual care group, those who received CBT showed statistically significant and lasting reductions in problem rating and improvements in quality of life. CBT could, therefore, be an important alternative or additional treatment option for patients with breast cancer (panel 2
Panel 2. Research in context
We searched OvidSP using a combination of the terms cognitive “behavio*”, “hot flush*”, “hot flash*”, “menopaus*”, and “breast cancer”. We found three relevant studies. One study was the MENOS1 single-group pilot trial,18
in which weekly 1·5 h sessions of cognitive behavioural therapy (CBT) for 6 weeks resulted in an average 49% reduction in problem rating and 38% reduction in hot flushes and night sweats (HFNS) frequency, maintained at 3 months' follow-up. A larger randomised controlled trial of CBT and exercise,33
which used the group protocol manual developed for MENOS 1,18
reported preliminary findings in which frequency and problem-rating reduced compared with usual care, although detailed findings are not available. In another single-group trial,34
an instructional DVD of paced breathing and distraction used over the course of 1 week resulted in small reductions in bothersomeness and interference of HFNS and no change in physiologically measured hot flush frequency. CBT shows some promise but adequately powered randomised controlled trials are needed.
Our findings show that group CBT can reduce the effect of hot flushes and night sweats for women who have had breast cancer treatment. These reductions were sustained and associated with improvements in mood, sleep, and quality of life. Group CBT seems to be a safe, acceptable, and effective treatment option which can be incorporated into breast cancer survivorship programmes and delivered by trained breast cancer nurses.
Limitations of this study include the frequency measures, which had high variability. The main subjective measure (hot flush rating scale) is retrospective—daily diary measures might be more reliable. However, findings from another study show evidence of the validity of this scale compared with daily diary measures.24
Estimation of the frequency of night sweats with the hot flush rating scale can be more difficult because women do not report night sweats that they sleep through, but this limitation is common to all self-report measures. The physiological measure was used for 24 h at baseline and at 9 weeks after randomisation; in view of the variability of this measure, future studies might include a longer time of SSC monitoring and also include this measure at follow-up assessments. Additionally, we did not control for all potential confounding factors that could have an effect on menopausal symptoms, such as the use of drugs to manage HFNS and the use of adjuvant hormone therapy. Health behaviours might also have affected HFNS and other secondary outcomes, but were not controlled for in the analyses (eg, caffeine intake). Finally, we do not know whether HFNS were caused by breast cancer treatments or whether women were naturally menopausal when they had breast cancer. However, treatment options are still restricted for these women, so a need still exists for non-hormonal interventions.
Our findings suggest that this cognitive behavioural treatment, designed to be delivered by trained health professionals such as breast-care nurses, has the potential to improve long-term health outcomes for patients with breast cancer, and could be incorporated into breast cancer survivorship programmes.