Women who have been treated for breast cancer identify vasomotor symptoms, such as hot flushes and night sweats, as a serious problem. These symptoms can be unpleasant, with a significant impact on daily life and sleep quality:

"It's as though somebody has built a furnace inside of you and it's your whole body. It starts almost at your feet and works up and you just feel as though you are literally on fire inside and it's trying to escape and you just want to escape but you can't escape, there's nowhere to go and nothing to do[1].

The social consequences of this embarrassing experience can affect employment, personal relationships and quality of life:

Umm, when they were at their worst I would be yeah pretty much dripping in, in err, various places umm err from really from the nose downwards; the lips; the neck; umm chest and back; crooks of my arms. And I could, you know, often if I was sitting down I would get up and my trousers would be really wet and it would go right down to my toes[1].

Oestrogen replacement remains the most effective treatment for hot flushes. However, this is contraindicated in the majority of women with oestrogen-dependent breast cancer. An estimated 550 000 people live in the UK today with a diagnosis of breast cancer and up to 70% experience hot flushes [2–5], which are exacerbated by a lack of safe and effective management strategies [4].

Although hot flushes may occur for a number of reasons, including natural or chemotherapy-induced menopause, they may also be side-effects of adjuvant hormonal therapies, such as tamoxifen and the aromatase inhibitors. Two recent clinical trials (aTTom [6] and ATLAS [7]) showed that 10 years of tamoxifen significantly reduces the risk of recurrence and breast cancer mortality. However, an increasing number of studies report that over 50% of women do not adhere to 5 years of endocrine treatment with an associated increase in mortality [8]. The lack of effective management of vasomotor symptoms may be an important contributory factor to this lack of adherence [9].

The pathophysiology of hot flushes is poorly understood. Proposed mechanisms include altered peripheral vascular reactivity and a narrowed thermoneutral zone [10], although how this relates to oestrogen deprivation is not understood. Without a fuller understanding of the physiology, mechanisms and triggers it will be difficult to develop new targeted therapies.

Adrienne Morgan says ‘I was diagnosed with breast cancer eight years ago and continue to take anti-oestrogen drugs because my cancer has returned. I have had a hot flush every 45 minutes for the last eight years. It is difficult to convey to anyone who has never had a hot flush how awful they are; exhausting, embarrassing, agitating…. I am fatigued, unable to work, sleep is only possible with medication and every morning my bed is soaked. I have tried everything. Only the SSRIs have some effect by reducing the severity of the hot flushes (venlafaxine made me feel horrible so I take Citalopram) but they make me anorgasmic. It surprises me that there is not more basic research being done into the causes of hot flushes. After all, most women will have them at some stage in their lives – not just breast cancer patients – and now men with prostate cancer are getting them too’.