Epidemiology of breast carcinoma: Age, menstrual status, and exogenous hormone usage in patients with lobular carcinoma in situ.

Lobular carcinoma in situ (LCIS) of the breast is a neoplastic condition associated with premenopausal women and it is largely for this reason that LCIS has been considered to be an estrogen-dependent lesion. In this report we present the results of a study of age at diagnosis, menstrual status, and exogenous hormone usage in 59 women with LCIS and in 190 patients with duct carcinoma. When LCIS was associated with duct carcinoma, 46% of patients were postmenopausal and in the group that also had infiltrating lobular carcinoma 71% were postmenopausal. Nine of 39 (23%) patients whose only carcinoma was LCIS were postmenopausal, 56% were premenopausal and 21% were menopausal. Seven of the nine postmenopausal women had never used a hormone-containing medication. In a comparison group with only duct carcinoma, 59.4% were postmenopausal and 35.2% had taken a hormone preparation. The high proportion of postmenopausal patients with LCIS leaves considerable doubt as to whether all lesions termed LCIS are equally dependent on estrogens at all stages in their evolution. We found no evidence to link LCIS with exogenous hormone usage in postmenopausal women. Prospective studies of hormone levels in patients with LCIS and in their relatives may provide an explanation for persistence of the lesion in postmenopausal women and could aid in identifying women at risk of developing invasive carcinoma.