Lobular carcinoma in situ (LCIS) describes a condition in which there is abnormal cell growth in the lining on the lobules that don’t invade the wall of the lobules. LCIS is similar to atypical lobular hyperplasia (ALH) in that they both involve abnormal cell growth in the lobules, however, compared to ALH, LCIS is more extensive. Research shows that LCIS is found in about 0.5% to 1.5% of benign breast biopsies and in about 1.8% to 2.5% of all breast biopsies. LCIS has also been shown to occur at higher rates in premenopausal women at an average age of 49 at diagnosis. While LCIS is a benign condition and is not considered to be breast cancer, having LCIS puts a person at an approximately 7 to 12 times higher risk of later developing invasive breast cancer. For women diagnosed with LCIS, the risk of developing breast cancer in 10 years is 10% and after 20 years of an LCIS diagnosis, the risk is 20%.
There are three types of LCIS: classic, pleomorphic, and florid. In classic LCIS, the cells that line the breast lobules are smaller or similar in size. Following a diagnosis of classic LCIS, the risk of going on to develop invasive carcinoma is about 9 to 10 times higher as compared to the general population. Classic LCIS is also generally positive for estrogen and/or progesterone receptors and negative for HER2. In pleomorphic LCIS, the cells lining the breast lobules and larger and more abnormal looking. 72% to 100% of cases of pleomorphic LCIS are positive for estrogen receptors (ER), 50% to 100% of cases are positive for progesterone receptors (PR), and in 1% to 41% of cases HER2 is overexpressed. Florid LCIS describes a condition where the cells that line the lobules have grown into a large group and become a mass, usually with sections of dead cells in the middle (referred to as central necrosis).
There are no notable signs or symptoms of LCIS. Classis LCIS is generally not seen on mammograms, while pleomorphic and florid LCIS can sometimes be found in this way. However, all 3 types of LCIS are diagnosed by a breast biopsy, usually following a concerning mammogram result or while assessing another issue.
Treating and Managing LCIS
If you have been diagnosed with LCIS, there is no action that you need to take since it is not cancer. However, there are a few options available to you to manage your increased risk of breast cancer. Which option is most appropriate will depend on your individual situation and will depend on a number of factors, including if you have additional factors that put you at an increased risk of developing breast cancer. Options following a diagnosis of LCIS include:
Close monitoring and increased surveillance: After being diagnosed with LCIS, you might take a “wait and see” approach. While this option does not involve any drugs, surgery, or any other treatment, it does involve a closer monitoring of breast cancer signs and symptoms as well as increased screening mammograms. Additional breast screening methods might also be ideal.
Chemoprevention and aromatase inhibitors: Estrogen is a natural hormone in the body that has been found to increase the risk of developing breast cancer and making breast tumors grow. Certain drugs that reduce the risk of developing breast cancer by blocking the effects of estrogen may be suggested for individuals diagnosed with LCIS. Tamoxifen and raloxifene are two such drugs. Tamoxifen can be used by both pre- and post- menopausal women while raloxifene can only be used by postmenopausal women. Although tamoxifen is better at reducing a person's risk of developing breast cancer, raloxifene has fewer side effects.
Additionally, aromatase inhibitors, which stops the enzyme aromatase from changing other hormones into estrogen, may also be used by post-menopausal women to reduce their risk of developing breast cancer following a diagnosis of LCIS. It is important to note that these drugs only reduce the risk of getting ER-positive breast cancer, not ER-negative breast cancer. If you take any medicines with estrogen in them, such as birth control, your healthcare team may also suggest that you stop taking them.
Surgery: The risks and benefits of having surgery to treat LCIS must be taken into consideration since an LCIS diagnosis is not guaranteed to become a breast cancer diagnosis. Surgery may be most suitable if you are at high-risk of developing breast cancer due to factors other than LCIS. Whether you are high-risk or not, speak to your healthcare team regarding which surgical option would be most ideal for you. Surgical options for treating LCIS include:
- Ultrasound-guided, vacuum-assisted excision – A fairly non-invasive method that removes the abnormal areas of the breast tissue. This is a common approach and is especially relevant in the case of pleomorphic and florid LCIS which have a tendency to grow quickly.
- Lumpectomy – Involves removing the abnormal areas of the breast tissue along with parts of the surrounding tissue.
- Prophylactic mastectomy – The removal of the entire breast tissue in one or both breasts. This option may be considered more ideal for individuals who have other high-risk factors for developing breast cancer, such as having a family history of breast cancer or having dense breasts.
Lobular Carcinoma in Situ (LCIS) and Atypical Lobular Hyperplasia from Breastcancer.org
Atypical Hyperplasia from Cleveland Clinic
Lobular Carcinoma in Situ (LCIS) from American Cancer Society
Lobular Carcinoma in Situ from National Library of Medicine
Lobular Carcinoma in Situ (LCIS) from Susan G. Komen