{"registry": "ISRCTN", "registryId": "ISRCTN31488319", "source": "https://www.isrctn.com/ISRCTN31488319", "apiSource": "https://www.isrctn.com/api/trial/ISRCTN31488319/format/default", "fetchedAt": "2026-10-07T17:01:01.083343Z", "license": "CC BY 4.0", "licenseSource": "https://www.isrctn.com/page/faqs#licence-to-post", "study": {"title": "Anastrozole versus placebo in post-menopausal women at increased risk of breast cancer", "scientificTitle": "An international multi-centre randomised controlled trial of anastrozole versus placebo in post-menopausal women at increased risk of breast cancer", "acronym": "IBIS-II Prevention", "hypothesis": "Primary hypothesis: \nTo determine if anastrozole is an effective method of preventing breast cancer in postmenopausal women at increased risk of the disease.\n\nSecondary hypothesis:\n1. To examine the role of anastrozole in preventing oestrogen receptor positive breast cancer\n2. To examine the rate of breast cancer occurrence after cessation of anastrozole\n3. To examine the effect of anastrozole on breast cancer mortality\n4. To examine the effect of anastrozole on other cancers, cardiovascular disease, fracture rates, and non-breast cancer deaths\n5. To examine tolerability and acceptability of side effects experienced by women on the study", "primaryOutcome": "Breast cancer incidence", "secondaryOutcome": "Current secondary measures as of 23/02/2012:\n1. Breast cancer mortality\n2. Cardiovascular events \n3. Osteoporosis \n4. Other relevant side effects\n \nPrevious secondary measure:\n1. Breast cancer mortality\n2. Thromboembolic events \n3. Cardiovascular events \n4. Osteoporosis \n5. Other relevant side effects", "intervention": "\n\tIBIS-II Prevention is a randomised double blind study investigating the use of anastrozole versus placebo in breast cancer prevention. There are two treatment groups:\nGroup One: anastrozole \nGroup Two: placebo\nBoth the anastrozole and the placebo are tablets that are taken once a day for 5 years.\n\tDrug\n\tPhase III\n\tAnastrozole\n      ", "condition": "\n\tBreast cancer\n\tCancer\n\tBreast cancer\n      ", "studyDesign": "Randomized controlled trial", "overallEndDate": "2021-05-31T00:00:00.000Z", "clinicalTrialsGovNumber": "NCT00078832", "lastUpdated": "2025-04-24T15:30:18.566127673Z", "eligibility": {"inclusion": "All women must be post-menopausal and between the ages of 40 to 70 years.\nPostmenopausal status is defined as meeting one or more of the following criteria:\n1. Over the age of 60 years \n2. Bilateral oophorectomy\n3. Aged 60 years or under with a uterus and amenorrhoea for at least 12 months\n4. Aged 60 years or under without a uterus and with Follicle-Stimulating Hormone (FSH) more than 30 IU/L\n\nThe entry criteria will be age-dependent to reflect the increasing baseline risk with age.\n\nAged 45 to 70 years - the entry criteria are based on a relative risk of at least twofold and are similar to IBIS-I. At least one of the following must be satisfied:\n1. First degree relative who developed breast cancer at age 50 years or less\n2. First degree relative who developed bilateral breast cancer\n3. Two or more first or second degree relatives who developed breast or ovarian cancer\n4. Nulliparous (or first birth at age 30 years or above) and a first degree relative who developed breast cancer\n5. Benign biopsy with proliferative disease and a first degree relative who developed breast cancer\n6. Mammographic opacity covering at least 50% of the breast in absence of Hormone Replacement Therapy (HRT) use within the last 3 months\n\nAlso aged 60 to 70 years - because of their higher baseline risk, women aged 60 to 70 years can enter the study with a smaller relative risk:\n7. First degree relative with breast cancer at any age\n8. Age at menopause 55 years or older\n9. Nulliparous or age at first birth 30 years or above\n\nAged 40 to 44 years - who are postmenopausal (usually because of a bilateral oophorectomy) are eligible if they satisfy one or more of the following criteria (approximately fourfold risk or greater):\n10. Two or more first or second degree relatives who developed breast or ovarian cancer at age 50 years or less\n11. First degree relative with bilateral breast cancer who developed the first breast cancer at age 50 years or less\n12. Nulliparous (or first birth at age 30 years or above) and a first degree relative who developed breast cancer at age 40 years or less\n13. Benign biopsy with proliferative disease and a first degree relative who developed breast cancer at age 40 years or less\n\nAll age groups (40 to 70 years) - women who have had certain breast conditions will also be eligible. These are:\n14. Lobular Carcinoma In Situ (LCIS)\n15. Atypical ductal or lobular hyperplasia in a benign lesion\n16. Ductal Carcinoma In Situ (DCIS), diagnosed within the last six months, and treated by mastectomy. Oestrogen Receptor (ER) or Progesterone Receptor (PgR) status of DCIS must be known, and must be greater than 5% positive cells.\n17. Women with a ten year risk greater than 5%, who do not fit into the above categories (risk equivalent). All risk equivalent women must be approved by the Steering Committee Co-Chairman (London IBIS central office). These women must have clearly apparent family history and/or other risk factors indicating appropriate increased risk of breast cancer for their age. Particularly careful assessment of the risk-benefit for these women should be undertaken before a woman from this group is entered.\n\nAll women must have:\n1. Had a mammogram taken within the last year and showing no evidence of breast cancer\n2. Had a baseline bone mineral density scan within the last 2 years (dual-energy X-ray absorptiometry [DXA] either of hip, lumbar spine, forearm) and spinal X-ray\n3. Signed a consent form after receiving full information about the study", "exclusion": "Current exclusion criteria as of 23/02/2012\n1. Still having periods \n2. Have breast cancer, or have had breast cancer in the past (unless you have had DCIS - see criteria for specific age groups) \n3. Have had any other cancer in the last five years (except non-melanoma skin cancer or carcinoma in situ of the cervix or Hodgkin's disease if before the age of 30 and treated with mantle therapy. \n4. Have had tamoxifen, raloxifene or other Selective Estrogen Receptor Modulators (SERMs) for more than six months in the past 5 years. (women in IBIS-1 are eligible if they have been off the therapy for more than five years. \n5. Want to carry on taking HRT that contains oestrogen \n6. Have had (or are planning to have) your breast(s) removed (a mastectomy) to try and prevent breast cancer \n7. Have any other serious medical conditions \n8. have had treatment with non-approved experimental drugs during the 6 months before randomisation. \n9. History of Lactose or gluten intolerance. \n10. Life expectancy of less than 10 years or other medical condition which would significantly interfere with the ability to accept the trial treatment. \n\nPrevious exclusion criteria\n1. Still having periods \n2. Have breast cancer, or have had breast cancer in the past (unless you have had DCIS - see criteria for specific age groups) \n3. Have had any other cancer in the last five years (except non-melanoma skin cancer or carcinoma in situ of the cervix) \n4. Have had tamoxifen, raloxifene or other Selective Estrogen Receptor Modulators (SERMs) for more than three months in the past \n5. Have taken part in the IBIS 1 trial \n6. Want to carry on taking HRT that contains oestrogen \n7. Have had (or are planning to have) your breast(s) removed (a mastectomy) to try and prevent breast cancer \n8. Have any other serious medical conditions \n9. Have taken any other drug as part of a clinical trial within the last three months", "ageRange": "Adult", "gender": "Female", "participantType": "Patient"}, "recruitment": {"recruitmentStart": "2003-05-25T00:00:00.000Z", "recruitmentEnd": "2012-01-31T00:00:00.000Z", "recruitmentStatusOverride": "", "recruitmentStartStatusOverride": "", "targetEnrolment": "3500", "totalFinalEnrolment": "3864"}, "countries": ["United Kingdom", "England", "Australia", "Belgium", "Chile", "Denmark", "Egypt", "Finland", "Germany", "Hungary", "Ireland", "Italy", "Malta", "New Zealand", "Pakistan", "Peru", "Portugal", "Russian Federation", "Switzerland", "Türkiye"], "locations": [{"name": "Centre for Cancer Prevention", "city": "London", "state": "", "country": "United Kingdom", "zip": "EC1M 6BQ"}], "sponsors": [{"organisation": "Queen Mary University of London (UK)", "sponsorType": "University/education", "rorId": "https://ror.org/026zzn846"}], "funders": [{"name": "Cancer Research UK (CRUK) (UK)", "fundRef": "http://dx.doi.org/10.13039/501100000289"}]}, "studySha256": "eb0eb062305e97f6dc82af4f9677b95bb3f9adbf31c72dddfa983010b6452d2c"}