TY - JOUR
T1 - Laparoscopically Confirmed Endometriosis and Breast Cancer in the Nurses' Health Study II
AU - Farland, Leslie V.
AU - Tamimi, Rulla M.
AU - Eliassen, A. Heather
AU - Spiegelman, Donna
AU - Hankinson, Susan E.
AU - Chen, Wendy Y.
AU - Missmer, Stacey A.
N1 - Publisher Copyright:
© 2016 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.
PY - 2016/11/1
Y1 - 2016/11/1
N2 - OBJECTIVE: To investigate the association between laparoscopically confirmed endometriosis and the risk of breast cancer. Previous research on endometriosis and breast cancer has reported mixed results. METHODS: Our prospective cohort study included 116,430 women from the Nurses' Health Study II cohort followed from 1989 until 2013. Our primary analysis investigated the association between self-reported laparoscopically confirmed endometriosis and the risk of breast cancer. Breast cancer diagnosis was verified through medical records. Multivariable adjusted Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). Breast cancer was further classified by menopausal status at the time of diagnosis and tumor hormone receptor status verified through tissue microarrays when available and medical records. RESULTS: At baseline, 5,389 (5%) women reported laparoscopically confirmed endometriosis. Over 24 years of follow-up, 4,979 (3%) incident breast cancer cases were diagnosed. Women with endometriosis were not at higher risk for overall (adjusted HR 0.96, 95% CI 0.88-1.06), premenopausal (adjusted HR 1.05, 95% CI 0.89-1.23), or postmenopausal breast cancer (adjusted HR 0.93, 95% CI 0.80-1.07). However, associations varied by tumor hormone receptor status (P value, test for heterogeneity:.001), although women with endometriosis were not at increased risk of estrogen- and progesterone receptor-positive (ER+/PR+) tumors (adjusted HR 1.00, 95% CI 0.87-1.14) or ER- and PR- tumors (adjusted HR 0.90, 95% CI 0.67-1.21). Women with endometriosis reported 2.87 ER+/PR- breast cancer cases per 10,000 person-years compared with women without endometriosis (1.32/10,000 person-years), which resulted in nearly a twofold increased risk of ER+/PR- breast cancers (adjusted HR 1.90, 95% CI 1.44-2.50). CONCLUSION: Endometriosis was not found to be associated with overall risk of breast cancer in this study; however, endometriosis was significantly associated with an increased risk of ER+/PR- breast tumors, which should be interpreted cautiously.
AB - OBJECTIVE: To investigate the association between laparoscopically confirmed endometriosis and the risk of breast cancer. Previous research on endometriosis and breast cancer has reported mixed results. METHODS: Our prospective cohort study included 116,430 women from the Nurses' Health Study II cohort followed from 1989 until 2013. Our primary analysis investigated the association between self-reported laparoscopically confirmed endometriosis and the risk of breast cancer. Breast cancer diagnosis was verified through medical records. Multivariable adjusted Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). Breast cancer was further classified by menopausal status at the time of diagnosis and tumor hormone receptor status verified through tissue microarrays when available and medical records. RESULTS: At baseline, 5,389 (5%) women reported laparoscopically confirmed endometriosis. Over 24 years of follow-up, 4,979 (3%) incident breast cancer cases were diagnosed. Women with endometriosis were not at higher risk for overall (adjusted HR 0.96, 95% CI 0.88-1.06), premenopausal (adjusted HR 1.05, 95% CI 0.89-1.23), or postmenopausal breast cancer (adjusted HR 0.93, 95% CI 0.80-1.07). However, associations varied by tumor hormone receptor status (P value, test for heterogeneity:.001), although women with endometriosis were not at increased risk of estrogen- and progesterone receptor-positive (ER+/PR+) tumors (adjusted HR 1.00, 95% CI 0.87-1.14) or ER- and PR- tumors (adjusted HR 0.90, 95% CI 0.67-1.21). Women with endometriosis reported 2.87 ER+/PR- breast cancer cases per 10,000 person-years compared with women without endometriosis (1.32/10,000 person-years), which resulted in nearly a twofold increased risk of ER+/PR- breast cancers (adjusted HR 1.90, 95% CI 1.44-2.50). CONCLUSION: Endometriosis was not found to be associated with overall risk of breast cancer in this study; however, endometriosis was significantly associated with an increased risk of ER+/PR- breast tumors, which should be interpreted cautiously.
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U2 - 10.1097/AOG.0000000000001684
DO - 10.1097/AOG.0000000000001684
M3 - Article
C2 - 27741204
AN - SCOPUS:84992323228
SN - 0029-7844
VL - 128
SP - 1025
EP - 1031
JO - Obstetrics and gynecology
JF - Obstetrics and gynecology
IS - 5
ER -