How injecting small amounts of this very common household item could be the secret to tackling breast cancer… as researchers suggest stunning plan could also fight other tumours

When US President Donald Trump suggested during the pandemic that injecting people with disinfectant might treat the Covid-19 virus, he was widely ridiculed – but could there actually be some merit in the idea?

His remarks during a live press conference in 2020 followed reports that, in lab tests, disinfectant had destroyed Covid-19 virus particles on a hard surface in less than a minute. No scientists, however, had suggested injecting it into humans.

Fast forward five years and NHS researchers are running trials to see whether hydrogen peroxide, the main ingredient in disinfectant, could hold the secret to transforming breast cancer treatment for thousands of women.

Elsewhere, it is being tested to improve the treatment of other cancers and it is also thought to offer hope as a way to help chronic wounds heal.

A colourless liquid with a slightly sharp odour, hydrogen peroxide occurs naturally in tiny amounts in human tissue (as a by-product of cells burning energy) and is also found in plants, bacteria, the air and water.

It’s been mass-produced for more than 100 years for use in everything from rocket fuel to hair dye, medicines and disinfectant – Domestos multi-purpose disinfectant wipes are made with it, for example.

The UK Health Security Agency warns that, in high doses, it can cause abdominal pain, foaming at the mouth, vomiting, gastrointestinal bleeding, loss of consciousness and – in severe cases – death.

Yet a clinical trial at The Institute of Cancer Research in London is investigating whether injecting small amounts into breast tumours could boost the effectiveness of radiotherapy treatment.

More than 37,000 British women undergo radiotherapy for breast cancer each year.

The treatment is intended to kill off any lingering cells after a tumour has been surgically removed.

Although it’s effective, scientists are constantly looking for ways to get the same benefits from fewer sessions or lower doses – reducing patients’ risk of common side-effects such as red or peeling skin (around the treatment area), fatigue, nausea and vomiting.

Breast cancer radiotherapy can also lead to heart damage – and, in rare cases, raise the risk of developing other cancers later on.

The trial, involving more than 180 patients at five different NHS hospitals, is examining whether injecting a slow-release hydrogen peroxide gel will lead to the radiotherapy killing more cancer cells. The idea is that hydrogen peroxide increases the levels of oxygen in cancer cells, making them more likely to respond to radiotherapy.

‘We know that cancer cells generally have low levels of oxygen in them,’ says Dr Navita Somaiah, a consultant oncologist at The Royal Marsden Hospital in London, who is leading the study.

This is thought to be because tumours often grow at a faster rate than the blood vessels they need to supply them with oxygen.

‘And this makes them resistant to radiotherapy, as it requires good oxygen levels in cancer cells to enhance its effectiveness.’

This happens through a process called oxygen fixation – where the damage to a cancer cell’s DNA from radiotherapy gets ‘fixed’ into place by the oxygen, making it much harder for the rogue cell to repair itself.

Dr Somaiah told Good Health: ‘When we inject the hydrogen peroxide gel into the tumour, it breaks down into water and oxygen – and this increase in oxygen makes cancer cells less resistant to the radiotherapy.’

Half of the trial’s recruits are getting radiotherapy alone – the rest will have a disinfectant gel jab (directly into the tumour site under local anaesthetic) an hour before each treatment session.

Early trial results, involving a dozen volunteers with inoperable breast cancer, found that the treatment is safe (the gel contains a diluted form of hydrogen peroxide that’s six times weaker than levels used in disinfectant) and effective, improving the tumour-shrinking effects of radiotherapy.

And it’s cheap to make – hydrogen peroxide costs as little as £3 a litre.

Dr Somaiah says that, in principle, the disinfectant therapy could also work on other solid tumours treated with radiotherapy – trials in cervical cancer and head and neck cancer are also in the pipeline.

‘There’s nothing specific about breast tumours – except that they are easy to access for the injections,’ she told Good Health. ‘But this treatment has the potential to be applied to other solid tumours as well.’

Meanwhile, researchers at London Health Sciences Centre Research Institute in Ontario, Canada, are testing whether a hydrogen peroxide cream rubbed on the skin will cure common skin tumours such as basal cell carcinoma or squamous cell carcinoma.

Around 180,000 people a year in the UK are diagnosed with a basal cell carcinoma, and 25,000 or so with squamous cell carcinoma. They often appear on the face and head (because of too much sun exposure) and, although they are not as aggressive as malignant melanoma (a type skin cancer that can spread elsewhere and may prove fatal), they can cause scarring and disfigurement if not surgically removed.

The study in Canada, involving 51 patients, is based on earlier lab studies suggesting hydrogen peroxide cream can reduce tumour size and even banish them completely in about half of cases. Results are expected in the next year.

And scientists at the Mayo Clinic in Minnesota in the US are working on an electric bandage that can pump small amounts of hydrogen peroxide into hard-to-treat wounds, helping them heal.

It’s thought that this constant flow of the chemical stops the formation of bacterial ‘biofilms’ – layers of bacteria that slow the healing process – in the wound.

Results are not expected until 2029 but, if successful, this could be a significant medical breakthrough – more than 180 diabetes patients a week in the UK undergo lower limb amputations because of wounds that don’t heal.

It’s not just as a treatment that the disinfectant is helping medicine.

A Cambridge-based tech firm, Exhalation Technology, has developed a hair dryer-shaped device that detects tiny traces of hydrogen peroxide in the breath of patients to see if they have a serious lung condition called chronic obstructive pulmonary disease (COPD).

Affecting more than three million people in the UK, COPD is a condition where the airways become so inflamed that it’s hard to breathe. Smoking is a major risk factor and many sufferers end up having to wheel an oxygen cylinder around with them everywhere they go.

COPD is diagnosed through a combination of a patient’s clinical history, physical examination and lung function tests – but it can take five years or more to get a diagnosis, as it’s often misdiagnosed as asthma because symptoms are very similar.

The new gadget, called Inflammacheck, could detect COPD much sooner – allowing patients to benefit more from drugs such as inhaled steroids to open up the airways.

It has sensors that can detect the presence of hydrogen peroxide in breath samples – COPD sufferers have higher levels because it’s a by-product of inflammation in the lungs.

The results are displayed on the device in a matter of minutes, whereas lab tests can take 24 hours or more.