One in every thousand women who attend for breast screening is diagnosed with DCIS. This is when the breast cancer cells are completely contained within the breast ducts and have not spread into the surrounding breast tissue. DCIS may also be referred to as non-invasive or intraductal cancer. Most women with DCIS have no signs or symptoms so it is mostly found through breast screening.
The DCIS usually shows up on a mammogram as an area in which calcium has been deposited in the milk ducts (known as microcalcification). A small number of women with DCIS may have symptoms such as a breast lump or discharge from the nipple.
It is important to remember that DCIS is not harmful at this stage, but if it is left untreated it may, over a period of years, begin to spread into (invade) the breast tissue surrounding the milk ducts. It is then known as invasive breast cancer.
Some areas of DCIS will never develop into invasive breast cancer even with no treatment. However, treatment is usually given for DCIS because it is not currently possible to tell which areas will definitely develop into an invasive cancer.
How is DCIS treated?
The treatment almost always cures DCIS. If you have DCIS you will be referred to a breast surgeon or cancer specialist (oncologist). It is important to discuss with them the benefits and possible side effects of any treatment in your particular case.
The treatments offered for DCIS are removal: usually as a lumpectomy (removal of the area of DCIS and some surrounding healthy tissue), but sometimes by mastectomy (removal of the whole breast) if several areas are affected or if the area is large and high-grade. The surgery may be followed by radiotherapy or hormonal therapy.
The NHS Breast Screening Programme is funding The Sloane Project, to improve the quality of care for women with screen-detected DCIS and other non-invasive breast cancers and atypical hyperplasias.