Preinvasive Disease

The terms Ductal carcinoma in situ (DCIS) and Lobular carcinoma in situ (LCIS) refer to very early changes in the breast where abnormal cells have developed but have not spread beyond the basement membrane of the affected duct or lobule.

DCIS

This involves the larger ducts in the breast. As cells accumulate and die within the duct they can cause calcium to settle out of the bloodstream in these areas. Calcium shows up very well on an x-ray and so these changes are frequently identified on screening mammograms. Not all DCIS calcifies in the same way and the ammount of calcification does not always give an accurate indication of the extent of change in the tissue.

DCIS was seldom identified before the arrival of screening mammography. As screening has increased over the last few years the incidence of DCIS has gone up from 1% to over 20% of newly diagnosed breast cancer cases.

The progression from DCIS  to invasive cancer is slow and is not inevitable. Whilst some of these changes may never have progressed to invasive cancer in the patients' lifetime we cannot tell reliably which ones are likely to change and so all cases are treated.

DCIS is a very early change in the tissue and does not have the same implications as finding an invasive breast cancer.

The pathologist identifies three grades of DCIS. Low, intermediate and high grade. This grading indicates how active the cells are. High grade changes are the most likely to progress to invasive cancer.

Treatment involves excision of the abnormal area with a clear margin of healthy tissue.

With small abnormal areas partial mastectomy will be sufficient but you will usually be advised that the surgery needs to be followed by a course of radiotherapy to the breast to minimise the risk of recurrence.

If the changes in the breast are extensive then you will need to have a full mastectomy. This can be combined with breast reconstruction.

The prognosis after treatment for DCIS is very good as the change has been dealt with before any invasion or spread could occur. Ther is a chance (+/-10%) of local recurrence after breast conserving treatment and DCIS can also develop later on in the other breast. Regular checkups including annual mammograms will  detect any new changes.

LCIS

This  is an unusual and  particularly confusing condition to understand.

The change in the tissue is almost always discovered by accident when a biopsy is done to assess a lumpy area or a cluster of calcification seen on a mammogram.

Current opinion is that LCIS is not actually a "true cancer change" but rather a "marker of increased risk" of breast cancer developing in the future.

The risk applies equally to both breasts.

Management therefore consists of careful regular surveillance with clinical examination, ultrasound and mammography.

The alternative to surveillance is to consider a risk reducing option:

Prophylactic Tamoxifen that may reduce the risk by up to 50%

Prophylactic mastectomy that is estimated to reduce risk by about 90%.

Discuss these options carefully with your doctors and do not rush into any decisions.