BACKGROUND: Endocrine therapy initiation after @entity3821 ( @entity3821 ) is highly variable and largely unexplained. National guidelines recommend considering @entity440 for @entity1 with @entity172 receptor-positive (ER+) @entity3821 or who undergo excision alone. We evaluated endocrine therapy use after @entity3821 over a 15-year period in an integrated health care setting to identify factors related to initiation. METHODS: Female Group Health Cooperative enrollees ages 18-89 years with a @entity3821 diagnosis during 1996-2011 were eligible for inclusion. Endocrine therapy was identified through pharmacy records. @entity5 and treatment information were from @entity5 registry reports; demographics and other risk factors were from questionnaires and electronic medical records. Relative risks (RRs) and 95% confidence intervals (CIs) for endocrine therapy initiation were calculated using multivariable generalized linear models. RESULTS: We identified 727 @entity1 with a @entity3821 diagnosis, including 163 (22%) who initiated endocrine therapy (149 @entity440 , 14 aromatase inhibitor). Younger @entity1 were more likely to initiate endocrine therapy (RR 1.69; 95% CI 1.16-2.46 for ages 45-54 vs. 65-74 years). Compared with breast-conserving surgery (BCS) with radiation, @entity1 who had BCS alone (RR 0.46; 95% CI 0.25-0.84) or mastectomy (RR 0.54; 95% CI 0.39-0.75) were less likely to use endocrine therapy. ER testing increased from 4% of @entity3821 cases in 2001 to 71% in 2011; however, endocrine therapy initiation decreased from 58% of ER+ @entity3821 in 2001-2005 to 37% in 2009-2011. CONCLUSION: Increasing ER testing since 2001 has not corresponded to parallel @entity4903 . Age, surgery, and radiation were the primary factors associated with initiation. IMPLICATIONS FOR PRACTICE: National guidelines recommend considering @entity440 for @entity1 with @entity3821 ( @entity3821 ) who are @entity172 receptor-positive (ER+) or who undergo excision alone. In this study, the rapid increase in ER testing caused by @entity440 's approval in 2000 did not lead to @entity4903 , despite recognition of an increasing number of @entity3821 as ER+ each year. Contrary to the suggested guidelines, @entity1 who had breast-conserving surgery without radiation were less likely to use @entity440 than those who had radiation. Future Food and Drug Administration approval of new endocrine agents for @entity3821 (such as aromatase inhibitors) may provide an opportunity to reemphasize benefits by ER and surgery status.

XXXX Initiation After Ductal Carcinoma In Situ.

@entity1 :: ('9606', 'Species') :: ['women'] @entity172 :: ('MESH:D004967', 'Chemical') :: ['estrogen'] @entity3821 :: ('MESH:D002285', 'Disease') :: ['DCIS tumors', 'ductal carcinoma in situ', 'DCIS'] @entity440 :: ('MESH:D013629', 'Chemical') :: ['tamoxifen'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'Tumor'] @entity4903 :: ('MESH:D004700', 'Disease') :: ['increases in endocrine therapy initiation']
@entity440 :: (MESH:D013629,Chemical) :: ['Tamoxifen']
