More than half of women with DCIS are spared a mastectomy

Pre-op mammogram reduces the need for mastectomy in women with DCIS

Over 60 per cent of women who have a form of breast cancer in the milk ducts (DCIS) are spared a mastectomy, according to latest research published today in the British Journal of Cancer.

Researchers for the Sloane Project examined how the size of the DCIS - measured by both imaging and pathology - related to the surgeon's decision of whether to conserve or remove the breast.

They found that, out of 2,500 women who had DCIS detected by breast screening, around 70 per cent of patients had conservation surgery to remove the disease and save the breast.

Of those who had conservation surgery, 71 per cent only needed one operation to remove the cancer, 19 per cent needed a further operation and 10 per cent went on to have a mastectomy.

In situ (non-invasive) breast cancer is confined to the ducts or lobules of the breast and has not spread to the surrounding tissues of the breast or other parts of the body. It is therefore curable if removed completely, but if left untreated may become invasive breast cancer.

This research is part of a large review of screen-detected DCIS and its treatment over the past five years through the Sloane Project, investigating the best treatment methods for DCIS.

Dr Jeremy Thomas, study author and consultant pathologist from the Western General Hospital, Edinburgh said: "This study shows that comparing the size of tumours as measured by imaging to the actual size of the tumour removed at surgery, gives a clear indication of where to focus improvements in practice. The results are very encouraging showing that 90 per cent of patients offered breast conservation for DCIS have a successful surgical outcome, usually from one operation, and avoid mastectomy.

"Deciding the best surgery option for patients with in situ breast cancer is difficult and requires very careful pre-operative assessment to define the extent of disease. A mastectomy would almost always cure the disease but where possible we want to conserve the breast and only remove the tumour. In the future we would hope to see that, with improvements in imaging and pre-operative assessment, more women could avoid having mastectomies."

Professor Stephen Duffy, Cancer Research UK's professor of screening at Queen Mary University of London, said: "In the screening era, large numbers of breast cancers are diagnosed at the DCIS stage. We have a responsibility to see that these cancers are not overtreated. Therefore it is good to see that the vast majority do not get a mastectomy. There is clearly room for improvement in that we can further reduce the need for re-operation. This problem can and doubtless will be reduced by high-quality pre-operative imaging."

Sara Hiom, director of health information at Cancer Research UK, said: "In the past treatment for DCIS was nearly always mastectomy so it's really encouraging to see that now around 60 per cent of women with DCIS have only the affected area removed, along with a border of healthy tissue around it.

"It's important that women go for breast screening when invited. The programme is very successful at detecting early stages of the disease which means treatment can be much more effective."