What is DCIS?

Ductal Carcinoma-in situ is the name given to pre-cancerous changes in the breast. This is the stage before breast cancer and is different from breast cancer. Under the microscope, abnormal cells similar to cancer cells are seen within the breast ducts, but these cells do not have the ability to invade the surrounding tissue or to live outside the breast duct. As a consequence DCIS never spreads to the lymph nodes or away from the breast and for this reason is not life threatening in itself. If left untreated however, DCIS will often, though not always, turn into breast cancer with potentially more serious consequences.

How is DCIS diagnosed?

Ductal Carcinoma-in situ is most often discovered when you have a mammogram. In particular it produces fine specks of calcium which show up on a mammogram. A needle biopsy is usually required to make the diagnosis for certain. It is unusual to have any symptoms as DCIS does not cause any pain and only rarely leads to lump or to nipple discharge.

Treatment of DCIS

Ductal Carcinoma-in situ is nearly always treated by surgery. It is essential to remove all of the affected tissue in a way that leaves none of the problem behind. Often this can involve the removal of only a small area of breast tissue but if the changes are very extensive a mastectomy can sometimes be required. In these cases breast reconstructive surgery can be safely carried out at the same time as the mastectomy. Ductal Carcinoma-in situ is classified under the microscope according to its aggressive potential. High grade DCIS turns into breast cancer much more quickly and when it does turn into cancer it is of the more aggressive type. Low grade DCIS is the opposite taking many years to become cancerous and sometimes never going cancerous at all.

If it does become cancerous the type of cancer that evolves is of equally low grade, growing very slowly and often not spreading.  In cases of high grade DCIS we usually recommend the addition of radiotherapy to the breast to minimise the chances of further problems. Radiotherapy is occasionally also recommended in cases of intermediate grade DCIS, not of great benefit in low grade DCIS.

The success of the treatment for DCIS depends on the grade. There is very little chance that low grade DCIS will recur but approximately ¼ of all cases of high grade DCIS develop further DCIS (50%) or invasive breast cancer (50% of recurrences are invasive breast cancer). The addition of radiotherapy reduces the chance of recurrence by a half, giving a recurrence rate of approximately 12-13% in cases of high grade DCIS. Women who have a mastectomy have only a very small chance of recurrence (1%) even if they have high grade DCIS.

What is LCIS (Lobular Carcinoma In-Situ)?

In a similar way to DCIS (ductal carcinoma in-situ), lobular carcinoma in-situ (LCIS) is a pre-cancerous change in the cells of the breast. Under the microscope the appearance is distinct from DCIS because the abnormal cells crowd together and fill up the lobules of the breast rather than the milk ducts. The breast lobules are the glandular spaces at the end of the milk ducts, which produce milk. The cells of the lobules do not normally develop in a cancerous way and, it is probable that in lobular carcinoma in-situ, the abnormal cells arise from the very end of the smallest part of the milk duct where it joins into the breast lobule.  The abnormal cells then fill up the rounded spaces of the breast lobule as well as the end of the breast duct. In some cases LCIS and DCIS can occur together. In other cases it may be very difficult to tell the two conditions apart.

How is LCIS diagnosed?

LCIS does not normally show up on any type of x-ray or scan (mammography, ultrasound or MRI) and the problem is usually identified after a breast biopsy performed for some other reason. LCIS is then identified under the microscope when the tissue is examined by a pathologist.

What does it mean if you have LCIS?

Women who are found to have LCIS have a much higher chance of developing breast cancer than average. It is generally believed that LCIS increases the risk of breast cancer by about 6 times. The risk of breast cancer is not only applicable to the breast where the LCIS was diagnosed but also means that there is an increased risk of breast cancer in the opposite breast. However, the risk is 3 times greater in the breast with LCIS than in the opposite breast.The breast cancer risk is also greater in women who have a sub type of LCIS, termed pleomorphic lobular carcinoma in-situ.

Strangely it has been found that if breast cancer does develop it does not necessarily develop in the same part of the breast where the biopsy was taken from. This means that if LCIS is found it is usually spread out through other parts of the breast as well. Clearly this has implications for treatment.

Treatment of LCIS

LCIS is a generalised change throughout the breast so removal of just one area of breast tissue does not effectively prevent breast cancer. Additionally, the breast cancer risk also affects the opposite side, although only one third as much as the affected side. For this reason it is better to think of LCIS as a general warning sign or risk factor rather than a specific problem area that needs to be removed.

The increased breast cancer risk for LCIS applies to the whole of the breast and to a lesser extent the opposite breast. Although it would help to have a mastectomy to minimise the chances of breast cancer most surgeons agree that this is rather drastic. The alternative policy is to have regular mammograms and checks in an attempt to try and catch breast cancer early if it develops.