A simple blood test that promises to be better at spotting early-stage breast cancer than a mammogram has been hailed as a ‘game-changer’ for women’s health. The Trucheck test, which highlights cancer cells circulating in the blood, correctly identifies 92 per cent of breast cancers – around five percentage points higher than mammography.
But scientists say the real breakthrough is its enhanced ability to spot early-stage breast cancers that are so small they are difficult to pick up on scans, particularly among younger women. Breast cancer surgeon Professor Kefah Mokbel, who was involved in the research, predicted the blood test would lead to a ‘paradigm shift’ in screening for breast cancer. ‘Potentially, this test is a game-changer. It could transform breast cancer screening,’ he said.
Medical oncologist Dr Tim Crook, of The London Clinic private hospital, who is offering it to patients, said the test could even replace mammograms, adding: ‘We have a massive problem with late diagnosis of cancer in this country and it’s been difficult to think of ways to ameliorate that.’
In the test, a nurse withdraws 5ml of blood, which is processed to identify the presence of ‘circulating tumour cells’ (CTCs). These cells are almost always produced by cancerous tumours and are a highly accurate sign of cancer. In a case-controlled study involving blood samples from 9,632 healthy women and another 548 with breast cancer, Trucheck was able to correctly spot cancer where it existed 92 per cent of the time.
The test perfectly spotted late-stage cancer – where tumours have spread beyond the breast – by identifying 100 per cent of samples from women with Stage 3 or Stage 4 of the disease. It was not as accurate at spotting earlier-stage cancers, which produce fewer CTCs, but the results were still impressive – identifying 96 per cent of women with Stage 2 disease, where tumours are largely confined to the breast.
For Stage 1, where the cancer is small and only in the breast, accuracy was 89 per cent. Even for the ‘ductal carcinoma in situ’, also known as Stage 0, where there are pre-cancerous lesions that could develop into the disease, it identified 70 per cent of cases.
There were no false positives – in which a test indicates cancer exists but none is found – although another study found a handful.
By contrast, around one in ten positive mammograms is a false alarm, resulting in unnecessary treatment. Dr Crook said the blood test had other advantages over mammography, such as the lack of radiation, which raises cancer risk, and the ‘absence of the need for infrastructure’ such as clinics.
Women in England are invited for their first mammogram at 50, and then every three years until 71. Last year just 62 per cent of eligible women had the X-ray, in part due to the pandemic affecting services and attendance – meaning that while 1.2 million had a mammogram, resulting in almost 11,000 breast cancer diagnoses, 750,000 did not. Later diagnosis leads to poorer chances of survival.
Dr Crook said that if more women were diagnosed when their breast cancers were less developed, it would dramatically improve overall outcomes. When spotted at Stage 1 and 2, cure rates exceed 90 per cent ‘without high-tech treatment’.
The test could help women in their 40s, who are not normally offered NHS mammograms because they are relatively poor at spotting tumours in the denser breast tissue found among younger women. More than 10,000 women under 50 – most in their 40s – are diagnosed with breast cancer in the UK every year – a fifth of all cases. Often their cancers are only spotted late on when they have spread.
Prof Mokbel, of the London Breast Institute at Princess Grace Hospital, said the blood test results, published in the journal Cancers, ‘represent a pivotal step towards extending early breast cancer detection beyond the current screening age and to women not participating in the current screening programmes’.
The test has European approval for use in women over 40 but is still undergoing validation studies in the UK and the US. The same technology, developed by the Indian firm Datar, has been validated to accurately spot glioblastoma, an aggressive brain cancer.
Dr Crook said the test could eventually be used to screen annually for multiple cancers from a single sample of blood, adding: ‘If you can have a one-tube blood test that can reliably pick up all the common solid tumours, that would be fantastic. Your GP could do it.’ Simon Vincent, of the charity Breast Cancer Now, said: ‘Early detection can stop people dying. This method could be especially helpful for diagnosing breast cancer where the limits of mammography detection are pushed.’
