Lobular Carcinoma In Situ

What is lobular carcinoma in situ?

The term lobular carcinoma in situ (LCIS) is misleading. This lesion is more appropriately termed lobular neoplasia. Strictly speaking, it is not known to be a premalignant lesion, but rather a marker that identifies women at an increased risk for subsequent development of invasive breast cancer. This risk remains elevated even beyond 2 decades, and most of the subsequent cancers are ductal rather than lobular. Lobular carcinoma in situ is usually multicentric and is frequently bilateral. In a large prospective series from the National Surgical Adjuvant Breast and Bowel Project with a 5-year follow-up of 182 women with lobular carcinoma in situ managed with excisional biopsy alone, only 8 women developed ipsilateral breast cancer (4 of them invasive). In addition, 3 developed contralateral breast tumors (2 of them invasive).

Lobular Carcinoma in Situ Picture

Treatment option overview

Most women with lobular carcinoma in situ can be managed without additional local therapy after biopsy. No evidence is available that re-excision to obtain clear margins is required. Tamoxifen has decreased the risk of developing breast cancer in women with lobular carcinoma in situ and should be considered in the routine management of these women. The Breast Cancer Prevention P-1 trial of 13,388 high-risk women comparing tamoxifen to placebo demonstrated an overall 49% decrease in invasive breast cancer, with a mean follow-up of 47.7 months. Risk was reduced by 56% in the subset of 826 women with a history of lobular carcinoma in situ, and the average annual hazard rate for invasive cancer fell from 12.99 per 1,000 women to 5.69 per 1,000 women. In women older than 50 years, this benefit was accompanied by an annual incidence of 1 to 2 per 1,000 women of endometrial cancer and thrombotic events. Bilateral prophylactic mastectomy is sometimes considered an alternative approach for women at high risk for breast cancer. Many breast surgeons, however, now consider this to be an overly aggressive approach. Axillary lymph node dissection is not necessary in the management of lobular carcinoma in situ.