Lobular carcinoma in situ (LCIS): what it means, monitoring and treatment

Cancer Research UK explains that the breast is made up of branching ducts that end in small glands called terminal duct lobular units, which make breast milk after pregnancy. In LCIS these units fill with abnormal cells. The abnormal cells stay within the units and cannot spread into surrounding breast tissue, which is different from invasive breast cancer, where abnormal cells have broken through the ducts.

LCIS can be found in both breasts. Men can develop it but this is very rare. Doctors may call it a type of lobular neoplasia, meaning abnormal cells, and atypical lobular hyperplasia is a closely related finding with fewer abnormal-looking cells. LCIS is also different from invasive lobular breast cancer, which is a separate condition.

Cancer Research UK says LCIS does not usually show up on mammograms and normally does not cause symptoms. It is often diagnosed by chance during tests for other breast conditions, such as a biopsy. This is why many people are surprised to hear the term at all.

The NHS lists the symptoms that should prompt a GP visit for breast changes, including a lump or swelling in the breast, chest or armpit, skin changes such as dimpling, changes in size or shape, nipple discharge or nipple changes. Since LCIS itself rarely causes symptoms, any such changes are investigated at a breast clinic through the usual tests.

There are three main types: classic LCIS, pleomorphic LCIS and florid LCIS. Cancer Research UK says most people with classic LCIS do not need any treatment, although the doctor may take more breast tissue if the diagnosis was made on a core biopsy, to check the area for other changes. This can be done by surgery or by a vacuum-assisted biopsy guided by mammogram or ultrasound.

Rarer types such as pleomorphic and florid LCIS are treated in a similar way to ductal carcinoma in situ (DCIS), and you are more likely to be offered surgery than monitoring for these, usually a wide local excision to remove the abnormal area with surrounding normal tissue. Rarely a mastectomy is needed if the changes are widespread throughout the breast.

Because the risk of invasive breast cancer is increased, your doctor may suggest regular monitoring, sometimes called close or careful observation. Cancer Research UK says you might have a mammogram every year for 5 years, so that if a cancer develops it is picked up at a very early stage and treatment can start as early as possible.

In some situations the doctor may offer hormone therapy or surgery to keep your risk low. Some people take hormone therapy for 5 years to lower the risk of invasive breast cancer, called chemoprevention. The drugs include tamoxifen, anastrozole, raloxifene and exemestane, and the choice depends on whether you have been through the menopause.

Having LCIS does not mean you will get breast cancer, and the decision about monitoring or preventive treatment is made with the breast team according to your individual circumstances.

Hearing a term containing the word carcinoma can be frightening even when the diagnosis is not cancer. Cancer Research UK stresses that LCIS is not cancer and that most women with it will not develop breast cancer, but that it does warrant follow-up because the risk of invasive disease is slightly higher.

It can help to ask the breast team which type of LCIS you have, whether more tissue needs to be removed, what monitoring is planned and whether hormone therapy is an option for you. The NHS also advises checking your breasts regularly so you know what is normal for you and can notice changes in size, look or feel, and seeing a GP about any change that is not normal for you.