The study findings of the Australian Institute of Health and Welfare (AIHW) and National Breast and Ovarian Cancer Center (NBOCC) released today found that women diagnosed with ductal carcinoma in situ (DCIS) are at a significantly higher risk of being diagnosed with a subsequent invasive breast cancer.

The study called Risk of Invasive breast cancer in women diagnosed with ductal carcinoma in situ in Australia between 1995 and 2005 provides the first Australian information on the risk of the development of invasive breast cancer following a diagnosis of DCIS.

According to Dr Helen Zorbas, CEO NBOCC, DCIS is a non-invasive tumour arising from, and contained entirely within, a milk duct of the breast. About 1,600 women are diagnosed with DCIS each year in Australia.

The study have found that women who have been diagnosed with DCIS were about 4 times more likely to develop a subsequent invasive breast cancer as compared to the women of the same age range in Australia.

Christine Sturrock, the Head of the AIHW's Cancer and Screening Unit said that the risk was significantly higher for women who were diagnosed with DCIS when they were less than 40 years of age. Among these women, the risk of developing the invasive breast cancer was 20 times more than Australian women of the same age range.

Even though the risk of developing invasive breast tumour was higher in women diagnosed with DCIS, they generally had relatively small invasive breast cancers, and they were less likely to reach the lymph nodes.

Ms Sturrock said that the close medical surveillance that has been practiced may be responsible for earlier detection and diagnosis of the subsequent invasive breast cancer.

Dr Zorbas believes that this study is vital in building a thorough understanding of the risk of invasive breast cancer in Australian women subsequent to the diagnosis of DCIS. It also shows that ongoing medical surveillance is very important after the DCIS treatment.

Future research will focus on the determination of the types of DCIS that are strongly linked to heightened risk for developing subsequent invasive breast cancer, according to Dr Zorbas.