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dc.contributor.authorCuzick, Jen_US
dc.contributor.authorSestak, Ien_US
dc.contributor.authorForbes, JFen_US
dc.contributor.authorDowsett, Men_US
dc.contributor.authorCawthorn, Sen_US
dc.contributor.authorMansel, REen_US
dc.contributor.authorLoibl, Sen_US
dc.contributor.authorBonanni, Ben_US
dc.contributor.authorEvans, DGen_US
dc.contributor.authorHowell, Aen_US
dc.contributor.authorIBIS-II investigatorsen_US
dc.date.accessioned2020-01-06T12:08:36Z
dc.date.issued2020-01
dc.identifier.citationLancet (London, England), 2020, 395 (10218), pp. 117 - 122
dc.identifier.issn0140-6736
dc.identifier.urihttps://repository.icr.ac.uk/handle/internal/3484
dc.identifier.eissn1474-547X
dc.identifier.doi10.1016/s0140-6736(19)32955-1
dc.description.abstractBACKGROUND:Two large clinical trials have shown a reduced rate of breast cancer development in high-risk women in the initial 5 years of follow-up after use of aromatase inhibitors (MAP.3 and International Breast Cancer Intervention Study II [IBIS-II]). Here, we report blinded long-term follow-up results for the IBIS-II trial, which compared anastrozole with placebo, with the objective of determining the efficacy of anastrozole for preventing breast cancer (both invasive and ductal carcinoma in situ) in the post-treatment period. METHODS:IBIS-II is an international, randomised, double-blind, placebo-controlled trial. Postmenopausal women at increased risk of developing breast cancer were recruited and were randomly assigned (1:1) to either anastrozole (1 mg per day, oral) or matching placebo daily for 5 years. After treatment completion, women were followed on a yearly basis to collect data on breast cancer incidence, death, other cancers, and major adverse events (cardiovascular events and fractures). The primary outcome was all breast cancer. FINDINGS:3864 women were recruited between Feb 2, 2003, and Jan 31, 2012. 1920 women were randomly assigned to 5 years anastrozole and 1944 to placebo. After a median follow-up of 131 months (IQR 105-156), a 49% reduction in breast cancer was observed for anastrozole (85 vs 165 cases, hazard ratio [HR] 0·51, 95% CI 0·39-0·66, p<0·0001). The reduction was larger in the first 5 years (35 vs 89, 0·39, 0·27-0·58, p<0·0001), but still significant after 5 years (50 vs 76 new cases, 0·64, 0·45-0·91, p=0·014), and not significantly different from the first 5 years (p=0·087). Invasive oestrogen receptor-positive breast cancer was reduced by 54% (HR 0·46, 95% CI 0·33-0·65, p<0·0001), with a continued significant effect in the period after treatment. A 59% reduction in ductal carcinoma in situ was observed (0·41, 0·22-0·79, p=0·0081), especially in participants known to be oestrogen receptor-positive (0·22, 0·78-0·65, p<0·0001). No significant difference in deaths was observed overall (69 vs 70, HR 0·96, 95% CI 0·69-1·34, p=0·82) or for breast cancer (two anastrozole vs three placebo). A significant decrease in non-breast cancers was observed for anastrozole (147 vs 200, odds ratio 0·72, 95% CI 0·57-0·91, p=0·0042), owing primarily to non-melanoma skin cancer. No excess of fractures or cardiovascular disease was observed. INTERPRETATION:This analysis has identified a significant continuing reduction in breast cancer with anastrozole in the post-treatment follow-up period, with no evidence of new late side-effects. Further follow-up is needed to assess the effect on breast cancer mortality. FUNDING:Cancer Research UK, the National Health and Medical Research Council Australia, Breast Cancer Research Foundation, Sanofi Aventis, and AstraZeneca.
dc.formatPrint-Electronic
dc.format.extent117 - 122
dc.languageeng
dc.language.isoeng
dc.rights.urihttps://creativecommons.org/licenses/by/4.0
dc.subjectIBIS-II investigators
dc.subjectHumans
dc.subjectCarcinoma, Ductal, Breast
dc.subjectCarcinoma, Intraductal, Noninfiltrating
dc.subjectBreast Neoplasms
dc.subjectPlacebos
dc.subjectAromatase Inhibitors
dc.subjectTreatment Outcome
dc.subjectAdministration, Oral
dc.subjectIncidence
dc.subjectFollow-Up Studies
dc.subjectAdult
dc.subjectAged
dc.subjectMiddle Aged
dc.subjectFemale
dc.subjectUnited Kingdom
dc.subjectAnastrozole
dc.titleUse of anastrozole for breast cancer prevention (IBIS-II): long-term results of a randomised controlled trial.
dc.typeJournal Article
dcterms.dateAccepted2019-11-27
rioxxterms.versionofrecord10.1016/s0140-6736(19)32955-1
rioxxterms.licenseref.urihttps://creativecommons.org/licenses/by/4.0
rioxxterms.licenseref.startdate2020-01
rioxxterms.typeJournal Article/Review
dc.relation.isPartOfLancet (London, England)
pubs.issue10218
pubs.notesNo embargo
pubs.organisational-group/ICR
pubs.organisational-group/ICR/Primary Group
pubs.organisational-group/ICR/Primary Group/ICR Divisions
pubs.organisational-group/ICR/Primary Group/ICR Divisions/Breast Cancer Research
pubs.organisational-group/ICR/Primary Group/ICR Divisions/Breast Cancer Research/Endocrinology
pubs.organisational-group/ICR/Primary Group/ICR Divisions/Molecular Pathology
pubs.organisational-group/ICR/Primary Group/ICR Divisions/Molecular Pathology/Endocrinology
pubs.organisational-group/ICR/Primary Group/ICR Divisions/Molecular Pathology/Endocrinology/Endocrinology (hon.)
pubs.publication-statusPublished
pubs.volume395
pubs.embargo.termsNo embargo
icr.researchteamEndocrinologyen_US
dc.contributor.icrauthorDowsett, Mitchen


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