Lobular Carcinoma In Situ

Lobular carcinoma in Situ (LCIS) is an abnormal change in the lining of the lobules (milk producing areas) of the breast. Although its name includes carcinoma it is not considered a malignancy, unlike its counter part change in the ducts, Ductal carcinoma in situ (DCIS). This is largely due to the fact that lobular carcinoma in situ is a slowly progressive change and although there is an increased risk of later developing breast cancer, this may take many years and may occur in a different part of the breast or in the other breast. It is therefore regarded as a risk for developing breast cancer, possibly up to ten times normal population risk or around 1% risk per year of developing breast cancer. (1) An exception to this is the pleomorphic type which is less common but treated more like malignancy and requires complete excision. 



Presentation and Management

LCIS is uncommon, possibly occurring in around 1% of non palpable mammographic abnormalities. It may be seen in association with a mass or calcification on imaging and is often incidental, as the change itself often is not radiologically detectable. Often surgical excision is performed particularly if the imaging and needle biopsy pathology do not exactly agree(discordance). If open surgical excision is performed and only LCIS is seen then no further specific treatment is required. It is not necessary to achieve clear surgical margins as is required for invasive carcinoma or DCIS.

Further management revolves around surveillance and prevention given that these women are at increase risk of developing breast cancer. Unlike those with increased risk due to gene mutations who have a high risk premenopausally, these woman will have a slowly rising risk over a lifetime, so that prophylactic mastectomy is not a conventional treatment. An exception to this may be those with a strong family history and LCIS, as there is some evidence of even a higher risk of developing breast cancer in this group and its not unreasonable to offer prophylactic mastectomy.

Patients with a diagnosis of LCIS should have close surveillance, and at BreastCare we would advocate an annual mammogram and ultrasound as well as physical examination. MRI is a useful additional screening test, possibly adding an extra 5% or so pick up of cancer particularly in dense breasts. It should be noted that individually mammography, ultrasound and MRI all have their strengths and omitting one modality will  reduce the cancer detection rate.

An additional management strategy is blocking the effect of oestrogen which has been shown in studies to reduce risk of breast cancer development by 45-50 %. Tamoxifen can be used in pre-menopausal and postmenopausal women, and the drug class of aromatase inhibitors including exemestane have been shown to be beneficial in postmenopausal women. 

References:

Diseases of the Breast 4th Edition 2010 Lippincott, Williams & Wilkins