Ductal carcinoma in situ (DCIS) down under: patterns of diagnosis and treatment in BreastScreen Victoria

DCIS is a contentious component of breast cancer screening programs. Rates of diagnosis of DCIS within BreastScreen Victoria have risen from 15% of all cancers diagnosed in 1994 to 21% in 2001. Over one-half of the DCIS diagnosed is of a high grade.

BreastScreen Australia initially set as a standard that 10–20% of cancers detected should be DCIS. When revised standards were introduced in 2002, the upper limit for diagnosis was removed.

Most surgical treatment of DCIS is by wide local excision: 73.2% in 2001. However, a greater proportion of women diagnosed with DCIS in rural areas undergo mastectomy (32%) compared with women in urban areas (18%).

Initially around 20% of women diagnosed with DCIS by BreastScreen Victoria underwent axillary dissection. Following the first reporting of nodal status in 1996, research indicated that a majority of these procedures could be classed as inappropriate. This had a dramatic impact on practice, and since 1998 rates of axillary dissection have remained at around 10% of women diagnosed with DCIS.

While the biology of DCIS is not well understood, it is vital that screening programs are able to explain what we do know about DCIS in order to assist women who are making choices about whether to screen or how to deal with a diagnosis of DCIS.