DCIS and LCIS are both conditions that affect the breast.

The initials DCIS stand for ductal carcinoma in situ. DCIS may be discovered when a lump forms within the breast or the first sign may be the appearance of white specks (microcalcifications) on a routine breast X ray (mammogram).

With DCIS cancerous cells are confined to the inside of the ducts (fine tubes) within the breast. As they have not broken through the wall of the breast ducts to affect other breast tissue (become invasive) there is no risk of the cancer cells spreading. This is why DCIS is sometimes called a 'pre-cancerous condition'.

If left untreated, somewhere between a quarter to a half of all areas of DCIS will develop into invasive breast cancer.Treatment for DCIS is generally very successful with a high cure rate.

Treatment for DCIS depends on

• how much of the breast is affected
• its position in the breast
• its grading.

There are three grades of DCIS low, intermediate and high. The grade refers to how abnormal the cells look under the microscope and gives an idea how quickly the cells may develop into invasive breast cancer or how likely it is that DCIS may come back after surgery. Low-grade DCIS has the lowest risk of developing into an invasive cancer and high-grade the greatest risk.

A mastectomy used to be the main treatment for DCIS. Now, it's more common to remove just the breast tissue affected by DCIS with a small area (margin) of surrounding healthy tissue. This operation is called a wide local excision. However, if the area of DCIS is very large or if there are several areas of DCIS within the same breast, a mastectomy may be recommended.

Most women, who have a wide local excision, will also have radiotherapy, to help prevent DCIS or invasive breast cancer developing in the remaining breast tissue. (Ongoing studies are looking into whether women with low grade DCIS may not need additional radiotherapy)

There is some evidence that, following surgery and radiotherapy, hormone therapy with tamoxifen, may further reduce the risk of DCIS returning. This is most likely to benefit people who have DCIS with oestrogen receptors on the surface of the cells (ER positive DCIS). Studies are comparing tamoxifen with a newer hormone drug called anastrozole, to see if this is more effective in postmenopausal women, who have had treatment for DCIS.

The initials LCIS stand for lobular carcinoma in situ. LCIS is usually discovered as a chance finding after a woman has had a breast biopsy (removal of a small piece of tissue) or a breast lump removed.

Unlike DCIS, LCIS does not show up on mammograms and is usually discovered when a non-cancerous breast lump is removed and examined under the microscope.

LCIS is not a cancer but does increase the risk of breast cancer developing. The risk of breast cancer is increased in women who have LCIS and between 1 in 3 to 1 in 4 women with LCIS develop breast cancer at some time during their life.However most women with LCIS will not develop breast cancer and will never need treatment.

Once LCIS is discovered regular check-ups are recommended with breast examinations every 6-12 months and mammograms every one or two years so that any cancerous change is detected promptly.

Rarely, a woman with LCIS may make a personal decision to have both breasts removed (bilateral mastectomy). This tends to happen where there is a strong family history of breast cancer, or because a woman may have considerable feelings of anxiety about her risk of developing breast cancer.

A study called the International Breast Cancer Intervention Study (IBIS), which includes women with LCIS, has shown that tamoxifen may reduce the risk of LCIS developing into breast cancer in women who have had their menopause. Research is also looking at whether other types of hormonal therapy such as anastrozole can reduce the risk of LCIS developing into a breast cancer.