Thousands of women with a common form of breast cancer may not need any treatment at all, scientists suggested today.
Around a fifth of all breast cancers are a slow-growing type of the disease which is contained in the milk ducts, known as ductal carcinoma in situ (DCIS).
Under current UK guidance, treatment to tackle these early stage cancers involves surgery followed by radiotherapy to kill off any abnormal cells lurking in breast tissue.
But US researchers, who tracked hundreds of women with DCIS, have discovered that this barrage of treatment makes little difference to whether or not the cancer progresses — or survival.
The study compared outcomes of women who were given the standard therapies with those who were offered a ‘watch and wait’ approach.
This meant they were monitored using scans and physical exams every six months.
After two years, the group of women who weren’t treated were at no higher risk of developing a more invasive form of the cancer than those who were.
Experts today said the ‘provocative’ findings could pave the way for a new protocol for women with DCIS, which could be actioned in as little as five years.
Ductal carcinoma in situ, or DCIS, is a a slow-growing type of the disease which is contained in the milk ducts and routinely picked up by screening. Pictured, DCIS in breast tissue
Under current UK guidance, treatment to tackle the early stage cancer involves surgery which may then be followed by radiotherapy to kill off any abnormal cells lurking in the breast tissue
Professor Eun-Sil Shelley Hwang, an expert in radiology at Duke University in North Carolina, who presented the study at San Antonio Breast Cancer Symposium today said there was ‘a growing body of evidence that not all DCIS is destined to progress’.
She added: ‘Current practice may result in the over-treatment of women whose tumors are at low risk of progression.
‘This can lead to chronic pain, altered body image, reduced quality of life, and other side effects that may be avoidable.
‘If these results are replicated in further studies, I believe they will change how we practice. I’m going to be optimistic and say this could happen within five years.’
DCIS affects around 4,800 Brits a year and is becoming more common because it is readily diagnosed by breast screening.
It is sometimes referred to as ‘pre-cancer’ because in a minority of cases it can develop into invasive disease.
But doctors do not know which DCIS cases will be dangerous and which will not.
In the UK, women are offered a mammogram – a special form of X-ray – every three years, between the ages of 50 and 70, to spot the disease in its earliest stages.
Symptoms of breast cancer to look out for include lumps and swellings, dimpling of the skin, changes in colour, discharge and a rash or crusting around the nipple
In the study, researchers tracked 673 patients with one of the most common types of DCIS cancer.
Just under two thirds underwent monitoring instead of treatment, and the rest received surgery with or without radiotherapy.
Women in the monitoring group could elect to have surgery at any time, and it was given if the tumor showed signs of invasive progression.
Both groups could also opt to receive hormone therapy — which blocks hormones in the body that can help the cancer to grow.
Over a follow-up of two years, 8.7 per cent of the group who received treatment were diagnosed with invasive breast cancer.
This means the cancer had spread from where it began in the same breast to surrounding normal tissue.
By comparison, the figure stood at 3.1 per cent among the monitoring group who had neither radiotherapy or surgery.
The study, which was published today in the journal JAMA, also found slightly more women in the active monitoring group (71.3 per cent) opted to receive hormone treatment, compared to 65.5 per cent in the standard group.
Checking your breasts should be part of your monthly routine so you notice any unusual changes. Simply rub and feel from top to bottom, in semi-circles and in a circular motion around your breast tissue to identify any abnormalities
Yet among those who received endocrine therapy, the rate of invasive ipsilateral cancer was 7.15 per cent in patients who received care according to the current guidance.
The figure stood at 3.21 per cent in the active monitoring arm.
Professor Hwang said: ‘Omission of surgery has been highly controversial, with both patients and providers fearing that it might result in an unacceptably high rate of patients who develop invasive cancer.
‘The important point to make is these are early results.
‘While the results are provocative I don’t think they’re quite practice changing yet.
‘For those patients who have already decided that they refuse to have surgery, we’ve come up with active monitoring that is safe.’
She also told the San Antonio Breast Cancer Symposium: ‘This was a select group of patients who were low risk. We will need follow-ups in five and ten years first.
‘The active monitoring group would have had similar results if they had had surgery.
‘The small size of the invasive cancers that were detected are a sign that we didn’t delay diagnosis in a way that is harmful to patients.’
One in seven women in the UK are diagnosed with breast cancer in their lifetime — around 56,000 a year — making it the most common cancer in the UK.
The figure stands at roughly 300,000 annually in the US. Around 85 per cent of women diagnosed with breast cancer survive more than five years.