Study supports use of radiotherapy in localised breast cancer (DCIS)
A new study in the Lancet Oncology medical journal has shown that women with ductal carcinoma in situ (DCIS), the most common type of non-invasive breast cancer, may benefit from radiotherapy after surgery.
DCIS is a form of non-invasive cancer, where cells inside some of the ducts in the breast have started to become cancerous. However, the cells have not spread into the surrounding breast tissue or elsewhere in the body.
About 98 per cent of patients survive following treatment, but in some cases the disease may come back, or a new cancer can develop in the other breast.
The UK, Australia and New Zealand (UK/ANZ) DCIS trial found that women with DCIS were much less likely to develop invasive disease if they received radiotherapy after surgery.
The long-term study, which recruited 1,710 women between 1990 and 1998, also showed that women who were given the hormone therapy tamoxifen were much less likely to see the disease return after surgery.
Initial results published in 2003 (after an average follow-up of 4.4 years) suggested that, while radiotherapy halved the number of new invasive and local recurrences, tamoxifen had no significant effect.
But the latest results, after the participants had been followed up for longer, indicate that both radiotherapy and tamoxifen are beneficial.
Among patients who were treated with radiotherapy after surgery, the risk of new invasive cancer in the same breast fell by almost 70 per cent, while the chance of DCIS coming back in the same breast dropped by more than 60 per cent.
Radiotherapy treatment had no effect on the risk of cancer developing in the other breast.
Women who were given tamoxifen were 30 per cent less likely to have DCIS come back in the same breast, and 65 per cent less likely to have a new cancer develop in the opposite breast.
Tamoxifen was not found to reduce the risk of developing invasive cancer in the same breast as the initial DCIS.
In addition, women who received radiotherapy did not seem to gain any additional benefit from taking tamoxifen as well.
Kate Law, Cancer Research UK's director of clinical research, said: "These important trial results prove that a small but significant number of women may benefit from radiotherapy after surgery to reduce the risk of their DCIS coming back or developing into invasive cancer. Modern radiotherapy is a cornerstone of today's cancer treatment and in fact helps cure more people of the disease than cancer drugs.
"Our researchers are involved in international efforts to develop better ways of identifying which women with DCIS will go on to develop invasive breast cancer, so treatment can be better targeted at those most likely to benefit."