With more than 1,000 cases of cancer being diagnosed every day in the UK, most of us will be familiar with the staging terminology doctors use, from 1, meaning a cancer is small and contained to 4, when a cancer has spread to another body organ. But there’s one additional stage that many people don’t know about… and that’s the earliest stage, stage 0.
It’s the stage that Tina Knowles, Beyoncé's mum, recently spoke about, after a routine mammogram revealed she had stage 1 cancer. In an interview, Knowles revealed that her cancer might have been caught earlier – at stage 0 – if she hadn’t missed a screening due to Covid. ‘I didn’t know that there was a stage 0,’ she said. ‘I could’ve caught this at stage 0 if I hadn’t missed my mammogram.’
So what exactly is stage 0 cancer?
‘Stage 0 cancer is used to refer to abnormal cells that haven’t spread from the area they formed,’ says Good Housekeeping’s Dr Sarah Jarvis. ‘They could spread and lead to invasive cancer but they haven’t yet. It’s sometimes called carcinoma in situ. Several different cancers can be found at this very early stage, but perhaps the best-known forms of stage 0 cancer are in the cervix and the breast.’
There are more than 200 different cancers, explains Caroline Geraghty, senior cancer information nurse at Cancer Research UK – and not all of them have a stage 0. ‘Cancers such as leukaemias, lymphomas and myelomas – cancers of the blood and of the lymph glands – aren’t staged in the same way,’ she explains.
It’s solid tumours that can be graded a stage 0 – most usually, breast cancer, as very early changes can be picked up at routine mammograms. ‘With breast cancer, stage 0 cancer is known as ductal carcinoma in situ (DCIS), where abnormal cells are confined to the milk ducts. The ‘in situ’ means they haven’t spread,’ says Caroline.
Not all Stage 0 cancers will develop into stage 1 cancers, she adds. ‘Not every cancer in situ will break through the cancer cell and form a tumour. In fact, in many cases, the cancer would just stay like that. But to be on the safe side, they’re nearly always removed.’
Similar early changes can be found in other organs, such as the cervix or the colon. Melanomas can also have a stage 0. ‘That’s a melanoma in situ,’ says Caroline, ‘and it would be detected by a biopsy.’
Mammograms and other screening tools, such as colonoscopies, are vital for catching cancers at the earliest, most treatable stages. And while, as Caroline points out, stage 0 cancers might never progress, an early diagnosis gives people options for treatment before cancer potentially becomes more aggressive.
Will I have symptoms with a stage 0 cancer?
Stage 0 cancers are too small to cause noticeable symptoms, which is why they’re usually only picked up at routine mammograms, screenings or incidentally. ‘The best way to know if you have cancer is to know what’s normal for you and report anything that’s abnormal,’ says Caroline.
Happily, the prognosis for stage 0 cancer is very positive; the five-year survival rate for stage 0 breast cancer is nearly 99%.
‘With all cancers, the earlier abnormal cells are found and treated, the higher the chance of treatment being successful,’ says Dr Sarah Jarvis. ‘Treatment at this stage is also often much less invasive and extreme. It’s essential to get any cancer, including stage 0 cancer, followed up closely by a specialist, but the outlook is better than for almost any other form of cancer.’
For more information, visit cancerresearchuk.org, or call the nurse helpline freephone on 0808 800 4040, available from Monday to Friday, 9am to 5pm.
