Women who are treated for early breast cancer are twice as likely to develop and die from the disease up to 20 years later, new study shows

• Cancerous cells in milk ducts is considered treatable and non-life threatening
• Researchers wanted to ascertain the long-term risk for women diagnosed with it
• Most women with DCIS are only recalled for yearly mammograms for five years 

Women treated for early breast cancer are twice as likely to develop and die from an aggressive form of the disease up to 20 years later, a study has found.

Ductal carcinoma in situ (DCIS) – cancerous cells in the milk ducts – is considered treatable and non-life threatening. But researchers wanted to ascertain the long-term risk for women diagnosed with it.

They looked at 35,024 women in England diagnosed as having DCIS by the NHS breast screening programme from when it began in 1988 until March 2014. 

By December 2014, 2,076 women had developed invasive breast cancer – an incidence rate of 8.82 per 1,000 a year – and more than double the number expected from national rates.

Some 310 died from breast cancer – a death rate of 1.26 per 1,000 a year and 70 per cent more than expected from national rates. 

For both invasive breast cancer and death from breast cancer, the increases continued for at least two decades, reported the BMJ. 

However, most women with DCIS are only recalled for yearly mammograms for five years. After this, they are given a follow-up every three years up to the age of 70.

Professor Sarah Darby, from the University of Oxford, who led the research, said: 'Understanding more about this risk puts us in a better position to make informed decisions about how to treat and monitor women with DCIS to give them the best possible care and save lives.'

Study author Dr Gurdeep Mannu, from the University of Oxford, said: 'We have shown that women diagnosed as having DCIS detected by screening in England have experienced substantially increased risks of both invasive breast cancer and death from breast cancer compared with women in the general population, despite having lower overall mortality.

'The women with DCIS detected by screening had rates of both invasive breast cancer and death from breast cancer that, from a few years after diagnosis of DCIS, were more than double those of the general population, and the increases lasted until at least 20 years after diagnosis.

'The increases affected women of all ages.'