Lobular neoplasia: Long term risk of breast cancer and relation to other factors

BACKGROUND. Lobular (LN), also known as lobular carcinoma in situ, is an incident histologic finding in tissue removed surgery. Patients with LN are known to be predisposed to develop invasive or intraductal carcinoma (CA). This study investigate factors that influences the cancer risk in LN patients. METHODS. Analysis of data concerning term follow-up (median: 18 yrs) of 236 patients with LN identified in a pathologic review of more than 2000 biopsy specimens with benign ephithelial proliferative breast disease. RESULTS. The probability of CA developing in either breast in long term survivors after a biopsy that contained LN was approximately 1/3, which is 5.4 times (95% CE: 4.2-7.0) the rate in the general population. The relative risk (RR) tended to decrease with increasing age at diagnosis, but was approximately doubled RR: 1.8; 95% CI: 1.1-3.2) for patients with benign ephithelial breast disease preceding their initial diagnosis of LN risk remained markedly elevated for at least 20 years, and increased substantially if there was second operations showing LN from 4.9 95% CI: 3.7-6.4) after a single operation with LN to 16.1 (95% CI: 6.9-31.8) after a second such operation. CONCLUSION. LN is a maker of increased CA risk that is further exacerbated by episodes of preexisting benign breast epithelial proliferative changes, and that remains substantially elevated for many years.