EXOGENOUS SEX-HORMONE USE, CORRELATES OF ENDOGENOUS HORMONE LEVELS, AND THE INCIDENCE OF HISTOLOGIC TYPES OF SARCOMA OF THE UTERUS

BACKGROUND, We analyzed data from a population-based, multi-center, ca se-control study to determine whether the occurrence of histologic typ es of uterine sarcoma is related to exogenous hormone use and/or to tw o correlates of endogenous estrogens: excess weight and cigarette smok ing. METHODS, One hundred sixty-seven women with newly-diagnosed uteri ne sarcoma (56 leiomyosarcoma, 85 mixed mullerian tumors, and 26 endom etrial stromal sarcomas) were interviewed by telephone regarding possi ble risk factors for these neoplasms. For comparison, 208 women identi fied at random from the general population of the study areas were int erviewed as controls. RESULTS. Use of oral contraceptives was positive ly associated with the risk of leiomyosarcoma (odds ratios [OR] = 1.7, 95% confidence interval [CI] = 0.7, 4.1), primarily among women who l ast used these medications 15 or more years prior to diagnosis. Use of noncontraceptive estrogens was directly associated with the risk of m ixed mullerian tumors, but only among recent and long-term users of th ese medications. Women in the highest quantile of body mass index (gre ater than or equal to 27.5 kg/m(2)) one year prior to diagnosis were a t increased risk of each type of uterine sarcoma (leiomyosarcoma, OR = 2.5, 95% CI = 1.1, 5.7; mixed mullerian tumors, OR = 2.9, 95% CI = 1. 3, 6.7; stromal sarcoma, OR = 3.5, 95% CI = 1.1, 10.9). Women who had ever smoked cigarettes were at reduced risk of leiomyosarcoma (OR = 0. 6, 95% CI = 0.3, 1.1) and stromal sarcoma (OR = 0.5, 95% CI = 0.2, 1.2 ), but the relationship was not more pronounced among heavy smokers; n o association with smoking was observed with mixed mullerian tumors. C ONCLUSIONS. Several of these findings parallel those from studies of e ndometrial carcinoma, and may indicate a role for unopposed estrogen i n the etiology of histologic types of uterine sarcoma. (C) 1996 Americ an Cancer Society.