Lobular carcinoma in situ (LCIS) means abnormal cells are in the breast. LCIS is sometimes grouped with ductal carcinoma in situ (DCIS) as a type of non-invasive breast cancer, but it differs from DCIS in that it’s not a pre-cancer. The main difference is that LCIS cannot become an invasive cancer, even if it isn’t treated.
Since LCIS is not a true cancer or pre-cancer, often no treatment is recommended. Sometimes if a needle biopsy result shows LCIS , the doctor might recommend that it be removed completely (with an excisional biopsy or some other type of breast-conserving surgery) to help make sure that LCIS was the only thing there. This is especially true if the LCIS is described as pleomorphic or if it has necrosis (areas of dead cells), in which case it might be more likely to grow quickly.
Having LCIS does increase your risk of developing invasive breast cancer later on, so close follow-up is very important. This usually includes a yearly mammogram and a breast exam. Close follow-up of both breasts is important because women with LCIS in one breast have the same increased risk of developing cancer in both breasts. There isn’t enough evidence to recommend getting routine magnetic resonance imaging (MRI) in addition to mammograms for all women with LCIS, but it’s reasonable for women with LCIS to talk with their doctors about their other risk factors and the benefits and limits of being screened yearly with MRI.
A certain kind of LCIS, called pleomorphic LCIS, may be more likely to turn into invasive cancer than most types of LCIS. Some doctors feel that this kind of LCIS needs to be removed completely with surgery.
If you have LCIS, you may want to consider taking a hormone medicine such as tamoxifen or raloxifene (Evista) to help reduce your risk of breast cancer. You might also want to consider taking part in a clinical trial for breast cancer prevention, or discussing other possible prevention strategies (such as getting to a healthy weight or starting an exercise program) with your doctor.
Because LCIS is linked to an increased risk of cancer in both breasts, some women with LCIS choose to have a bilateral simple mastectomy (removal of both breasts but not nearby lymph nodes) to lower this risk. This is more likely to be a reasonable option in women who also have other risk factors for breast cancer, such as a BRCA gene mutation or a strong family history. This may be followed by delayed breast reconstruction.