Breast cancer survivors could benefit from taking statins, scientists believe, after discovering that lowering cholesterol activity halves the chance of the disease returning in 10 years.
Scientists have known for some time that the hormone oestrogen helps cancer to spread, which is why women are usually given anti-hormone treatments following chemotherapy and surgery.
But a new study from the Institute of Cancer Research has shown that breast cancers use cholesterol to produce a molecule which has the same impact as oestrogen. The molecule – called 25-HC- acts like a fuel to allow cancer cells to keep growing.
Lab trials showed that blocking the molecule prevents cancer spread by 50 per cent, a finding that cancer charities hailed as a ‘really crucial discovery.’
“Statins could be a valuable addition to breast cancer treatment, and that this warrants investigation in clinical trials”Dr Lesley-Ann Martin
Separate trials also showed that women whose genes encouraged the production of the cholesterol molecule were twice as likely to die within in 10 years.
The researchers suggest that taking statins to lower cholesterol could prevent breast cancer returning.
“During the course of treatment, breast cancers, that are ‘fed’ by oestrogen, often become resistant to standard hormone therapy,” said Dr Lesley-Ann Martin, group leader at the Breast Cancer Now Toby Robins Research Centre at The Institute of Cancer Research.
“Our research has demonstrated that these cancer cells can use a cholesterol molecule to mimic oestrogen so that they continue to grow without it.
“This is hugely significant. Testing the patient’s tumour for 25-HC or the enzymes that make it may allow us to predict which patients are likely to develop resistance hormone therapy, and tailor their treatment accordingly.
“Our study also demonstrates that statins could be a valuable addition to breast cancer treatment, and that this warrants investigation in clinical trials.”
Breast cancer uses hormones to fuel its spread
Breast cancer uses hormones to fuel its spread Credit: PA
The study looked at the most common type of breast cancer, known as ‘ER Positive’ which affect 80 per cent of the 40,000 women who are diagnosed each year.
Those women are at greater risk from oestrogen because their breast cells have more oestrogen receptors making them particularly sensitive to the hormone.
Anti-hormone drugs work by either reducing oestrogen in the body (known as aromatase inhibitors), by blocking the receptors themselves (tamoxifen), or by destroying the receptors entirely (fulvestrant).
But scientists were puzzled as to why the drugs often did not work for those women and set about trying to find out what was happening in the cells.
Around 12,000 ER-positive patients annually suffer a relapse during or following hormone treatment.
Cholesterol is an important molecule that allows the body to build and maintain cell membranes and produce a number of hormones.
Victoria Derbyshire’s last cancer treatment Play! 00:41
As well as obtaining cholesterol from food, the body produces its own cholesterol in a process called the cholesterol biosynthesis pathway. Blocking that pathway slowed down the proliferation of the cancer cells by up to 50 per cent.
“This is a really crucial discovery,” said Baroness Delyth Morgan, Chief Executive at Breast Cancer Now.
“Far too many women have to deal with the potentially devastating consequences of their breast cancer coming back and this research presents an important opportunity to improve the effectiveness of today’s most commonly used treatments.
“This study breaks new ground in uncovering how some breast cancers continue to survive without oestrogen and suggests that women could benefit from adding statins to standard anti-hormone treatments.
“But this is early research and greater clinical evidence is now needed to understand the potential risks and benefits of this approach.”
The findings were corroborated in patient trials involving nearly 1,000 breast cancer survivors.
The researchers say the findings support the idea that statins could improve prognosis for people who already have breast cancer.
Dr Áine McCarthy, Cancer Research UK’s senior science information officer, said: “This study provides a new clue to why some women’s breast cancer stops responding to hormone therapy, and may give doctors a potential new way to treat these patients.
“But clinical trials are needed to test whether anti-cholesterol drugs work the same way in patients as they do on cancer cells grown in the lab, to identify which women might benefit from taking these drugs, and to find out if there are any long term side effects.”
Jane Murphy, Clinical Nurse Specialist at Breast Cancer Care, added: “This early study raises an interesting question of whether cholesterol-reducing treatment, such as statins, could help lower the chances of breast cancer returning for some women who have developed a resistance to hormone therapy.”
“We know that many women can be consumed with fear of their breast cancer coming back, which can have a huge impact on their ability to move forward after treatment. This discovery may, in future, help reduce these concerns for some patients, by allowing doctors to test if their cancer is likely to return, and tailor treatment accordingly.
“However, this research is only in its initial stages. We look forward to seeing further trials to determine whether this approach could work in practice.