Women with low levels of ‘friendly bacteria’ in their vagina may be more likely to get ovarian cancer

• Women with the disease have less of the strain lactobacilli in their genitals 
• Those who carry the BRCA1 gene, which raises the risk, also have lower levels
• Could lead to a smear-like test that looks for the bacteria to determine the risk 

Women with lower levels of ‘friendly’ bacteria in their vaginas may be more at risk of ovarian cancer, research suggests.

A study found women with the disease have less of the strain lactobacilli in their genitals. 

And those who carried the BRCA1 gene, which raises the risk of ovarian cancer by up to 42 times, also had lower levels of the bacteria.

Lactobacilli is crucial to maintaining the vagina’s acidic pH, which helps to prevent ‘bad’ bacteria from causing infections. 

Many women with a family history of ovarian cancer resort to having their ovaries removed to reduce their risk of the disease, leaving them infertile. 

The researchers hope their ‘tantalising’ study will lead to a smear-like test that detects a woman’s cancer risk by her bacterial levels, helping her avoid surgery.

A suppository could even be developed for at-risk women to put in their vaginas to boost its bacterial numbers, they add. 

Women with less ‘good’ bacteria in their vaginas may be more at risk of ovarian cancer (stock)

The research was carried out by University College London and led by Professor Martin Widschwendter, of the department of women’s cancer.

‘It’s the first time we have been able to demonstrate women with gene mutations have a change in their vaginal microbiome,’ Professor Widschwendter said.       

‘This novel approach could revolutionise the way we can intervene and change the implications of being at high risk of ovarian cancer development.’

He told the BBC: ‘We do not yet know for sure whether low levels of the beneficial bacteria leads to an increased risk of ovarian cancer, but that is what we suspect.

‘It fits with other research. It’s been shown that women who use excessive vaginal hygiene products have lower levels of this bacterium too and they are at increased risk of ovarian cancer.’

Around 7,300 women are diagnosed with ovarian cancer every year in the UK, Target Ovarian Cancer statistics show. 

And in the US, 22,530 women are expected to be told they have the disease in 2019, according to the American Cancer Society. 

Symptoms tend to be vague, and include bloating, feeling full and abdominal discomfort. This makes the disease difficult to diagnose, with many cases only being spotted once it has spread.

Unlike for breast and cervical cancer, there is no screening programme for ovarian forms of the disease in the UK or US. This is due to no reliable test being available. 

To uncover whether vaginal bacteria affects the risk, the researchers analysed cervical screening swabs collected from 580 women living in the UK, Czech Republic, Germany, Italy or Norway.

Some of the women, who were aged 18-to-87, had recently being diagnosed with ovarian cancer or carried the BRCA1 gene. 

The rest of the participants had neither cancer nor abnormal BRCA1, and acted as the study’s controls. 

BRCA1 produces proteins that repair damaged DNA, suppressing tumour formation. If the gene is mutated, these proteins do not get made or do not function correctly.

Around 44 per cent of women who inherit a harmful BRCA1 mutation will develop ovarian cancer, compared to just 1.3 per cent of the general population, according to the National Cancer Institute.  

WHY OVARIAN CANCER IS CALLED A ‘SILENT KILLER’ 

About 80 percent of ovarian cancer cases are diagnosed in the advanced stages of the disease.

At the time of diagnosis, 60 percent of ovarian cancers will have already spread to other parts of the body, bringing the five-year survival rate down to 30 percent from 90 percent in the earliest stage.  

It’s diagnosed so late because its location in the pelvis, according to Dr Ronny Drapkin, an associate professor at the University of Pennsylvania, who’s been studying the disease for more than two decades.

‘The pelvis is like a bowl, so a tumor there can grow quite large before it actually becomes noticeable,’ Dr Drapkin told Daily Mail Online.

The first symptoms to arise with ovarian cancer are gastrointestinal because tumors can start to press upward.

When a patient complains of gastrointestinal discomfort, doctors are more likely to focus on diet change and other causes than suggest an ovarian cancer screening.

Dr Drapkin said it’s usually not until after a patient endures persistent gastrointestinal symptoms that they will receive a screening that reveals the cancer.

‘Ovarian cancer is often said to be a silent killer because it doesn’t have early symptoms, when in fact it does have symptoms, they’re just very general and could be caused by other things,’ he said.

‘One of the things I tell women is that nobody knows your body as well as you do. If you feel something isn’t right, something’s probably not right.’

Results – published in The Lancet Oncology – revealed that of the women with ovarian cancer, 60 per cent had less than half of their vaginal microbiome populated by lactobacilli.

This is compared to the the low-risk women whose vaginal microbiome’s were dominated by the bacteria. 

The results also showed the women who carried a ‘faulty’ BRCA1 had almost three times less lactobacilli than those without the genetic mutation.

More than a quarter of the women who were under 30 and had the genetic mutation had low levels of the bacteria.

This is compared to none of the under 30-year-olds without a faulty BRCA1. 

Participants who had close family members with ovarian cancer also had less lactobacilli. 

Many women with a family history of cancer, or those that know they carry a BRCA mutation, have their ovaries and fallopian tubes removed at a young age.

While this prevents ovarian cancer taking hold, it leaves women infertile and can trigger an early menopause.  

The researchers hope that by using lactobacilli as an indicator of a woman’s cancer risk, more will be able to postpone surgery and preserve their fertility.

Athena Lamnisos, CEO of the Eve Appeal, said: ‘As a woman at high risk of cancer development you are faced with one stark choice – to undergo life-changing surgery to reduce your risk.

‘This decision is not easy for many women, with implications for their fertility, being plunged into early menopause and the fact of undergoing surgery.

‘This research is an exciting step forward in both understanding the factors that potentially impact on cancer development but also, and most importantly, in developing interventions that can reduce that risk.

‘If that can be done by something as simple as adjusting the vaginal microbiome – that is a game-changer.’

The researchers hope to carry out further studies to determine whether introducing healthy bacteria into a woman’s vagina reduces her risk of developing ovarian cancer.

This could be as simple as regularly using a vaginal suppository.

Dr Adam Rosenthal, director of familial gynaecological cancer clinic at UCL Hospitals NHS Foundation Trust, said: ‘This study raises the tantalising possibility that something as simple as a tablet placed in the vagina could prevent ovarian cancer.’

The researchers will first look at whether ‘unfriendly’ bacteria are found in the fallopian tubes, which is where most ovarian cancers start. 

Alexandra Holden, director of communications at Target Ovarian Cancer, added: ‘Anything that furthers our understanding of the causes of ovarian cancer is to be enthusiastically welcomed. 

‘Before women become concerned about the bacteria in their vagina, more research is required to better understand how the vaginal microbiome may contribute to ovarian cancer, and find better ways to detect the disease. 

‘In the meantime, it is crucial for women to be aware of the symptoms, and to visit the GP with any concerns.’ 

Public health minister Seema Kennedy said she was ‘delighted’ by the new research, which is the first to be funded by the Government’s tampon tax.

‘We are committed to preventing and diagnosing cancer earlier as part of our long-term plan for the NHS,’ she said.

‘This new research will be vital for improving our understanding of the risk factors for women.

‘It is just one of many innovative programmes in women’s health enabled by the Tampon Tax and I look forward to seeing more great work like this in the near future.’ 

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