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Anastrozole (Monograph)

Brand name: Arimidex
Drug class: Antiestrogens
- Aromatase Inhibitors
VA class: AN900
Chemical name: α,α,α′,α′-Tetramethyl-5-(1H-1,2,4-triazol-1-ylmethyl)-1,3-benzenediacetonitrile
Molecular formula: C17H19N5
CAS number: 120511-73-1

Medically reviewed by Drugs.com on May 22, 2023. Written by ASHP.

Introduction

Antineoplastic agent; selective aromatase inhibitor (type II).1 16

Uses for Anastrozole

Initial, Sequential, or Extended Adjuvant Therapy for Postmenopausal Women with Early-Stage Hormone Receptor-Positive Breast Cancer

Initial (primary) adjuvant therapy in postmenopausal women with early-stage hormone receptor-positive breast cancer.1 24 50 57 66 68 10002 10029

Sequential adjuvant therapy† [off-label] following 2–3 years of adjuvant tamoxifen for early-stage hormone receptor-positive breast cancer in postmenopausal women.51 52 53 63 64 65 78 10019 10053 10075

Extended adjuvant therapy† [off-label] following 5 years of adjuvant tamoxifen for early-stage hormone receptor-positive breast cancer in postmenopausal women.54 75 81 10019

Guidelines from ASCO states that postmenopausal women with node-positive hormone receptor-positive breast cancer should be offered extended adjuvant endocrine therapy with one of the following: aromatase inhibitor therapy for up to a total of 10 years; tamoxifen for 10 years; tamoxifen for 5 years, then an aromatase inhibitor for 5 years; or tamoxifen for 2–3 years, then an aromatase inhibitor for 7–8 years.10019 Women with node-negative breast cancer may also be offered extended adjuvant endocrine therapy for up to a total of 10 years, but benefits are likely narrower due to lower risk for recurrence.10019

Consider adverse effects, patient preference, and preexisting conditions when selecting an adjuvant regimen; during the course of adjuvant therapy, patients who are intolerant of one treatment may be switched to a different treatment.10075

Adjuvant Therapy for Early-stage Breast Cancer in Premenopausal Women

Use of endocrine therapy (i.e., anastrozole, exemestane, letrozole, tamoxifen) in combination with ovarian suppression† [off-label] as adjuvant therapy in premenopausal women† [off-label] with early-stage hormone receptor-positive breast cancer may be considered a reasonable choice (accepted).79 10010 10011 10012 10013 10023 10026 10028

Advanced Breast Cancer in Postmenopausal Women

First-line therapy for hormone receptor-positive (i.e., estrogen receptor-positive, progesterone receptor-positive, or both) or hormone receptor-unknown locally advanced or metastatic breast cancer in postmenopausal women.1 21 22 40 55 56 76

Second-line therapy for advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy.1 2 8 23 56 82 83 84 Usually ineffective in patients with estrogen receptor-negative breast cancer and those who fail tamoxifen therapy.1

According to ASCO, combination therapy with a nonsteroidal aromatase inhibitor (e.g., letrozole, anastrozole) and a cyclin-dependent kinase (CDK) 4/6 inhibitor should be offered first line to postmenopausal patients with treatment-naive hormone receptor-positive metastatic breast cancer; for some patients, monotherapy with an aromatase inhibitor may be appropriate.4000 Choice of second-line hormonal therapy should take into account prior treatment exposure and response to previous endocrine therapy; options for second-line therapy include tamoxifen, an aromatase inhibitor, or fulvestrant with or without everolimus.4000

Advanced Breast Cancer in Premenopausal Women

For first-line treatment of premenopausal women with treatment-naive, hormone receptor-positive metastatic breast cancer† [off-label], ASCO recommends combination therapy with a nonsteroidal aromatase inhibitor (e.g., letrozole, anastrozole) and a CDK 4/6 inhibitor, in conjunction with chemical ovarian function suppression.4000 Ovarian suppression or ablation in combination with hormonal therapy should be offered to premenopausal women with metastatic hormone receptor-positive breast cancer; patients without prior exposure to hormonal therapy may be treated with tamoxifen or ovarian suppression/ablation alone, but combination therapy is preferred.4000

Reduction in the Incidence of Breast Cancer in Women at High Risk

Has been used for reduction in the incidence of breast cancer† in women at high risk for developing the disease.77 80 10050 10055

Anastrozole Dosage and Administration

General

Pretreatment Screening

Patient Monitoring

Other General Considerations

Administration

Oral Administration

Administer orally once daily without regard to meals.1

Dosage

Adults

Breast Cancer
Initial, Sequential, or Extended Adjuvant Therapy for Postmenopausal Women with Early-Stage Hormone Receptor-Positive Breast Cancer
Oral

1 mg once daily.1

Optimum duration unknown; duration of therapy in clinical study was 5 years.1

Sequential and/or extended adjuvant therapy†: ASCO states that postmenopausal women with node-positive hormone receptor-positive early breast cancer should be offered extended adjuvant endocrine therapy with one of the following: aromatase inhibitor therapy for up to a total of 10 years; tamoxifen for 10 years; tamoxifen for 5 years, then an aromatase inhibitor for 5 years; or tamoxifen for 2–3 years, then an aromatase inhibitor for 7–8 years.10019 Women with node-negative breast cancer may also be offered extended adjuvant endocrine therapy for up to a total of 10 years, although benefits are likely narrower due to lower risk for recurrence.10019

Adjuvant Therapy for Early-Stage Breast Cancer in Premenopausal Women†
Oral

Dosage of 1 mg once daily has been used in combination with ovarian suppression†.79 10023

Advanced Breast Cancer in Postmenopausal Women
Oral

1 mg once daily.1 Continue therapy until tumor progresses.1

Reduction in the Incidence of Breast Cancer in Women at High Risk†
Oral

Dosage of 1 mg once daily for 5 years has been used.77 10050

Special Populations

Hepatic Impairment

Dosage adjustment not required in patients with mild to moderate hepatic impairment or stable hepatic cirrhosis.1

Not studied in patients with severe hepatic impairment.1

Renal Impairment

Dosage adjustment not required.1

Geriatric Patients

Dosage adjustment not required.1

Detailed Anastrozole dosage information

Cautions for Anastrozole

Contraindications

Warnings/Precautions

Ischemic Cardiovascular Effects

Increased incidence of ischemic cardiovascular events (e.g., angina pectoris) reported in patients with preexisting ischemic heart disease; consider risks and benefits of therapy in these patients.1

Bone Effects

Bone mineral density (BMD) at lumbar spine and hip decreased in patients receiving anastrozole and increased in those receiving tamoxifen as initial (primary) adjuvant therapy.1 43 48 Incidence of fractures was higher with anastrozole versus tamoxifen during treatment, but not following completion of treatment.1 66

Consider BMD monitoring in patients receiving anastrozole.1

Cholesterol

Increases in total serum cholesterol reported during therapy.1

Consider cholesterol monitoring in patients receiving anastrozole.1

Fetal/Neonatal Morbidity and Mortality

May cause fetal harm; embryotoxic and fetotoxic in animals.1 Test for pregnancy prior to initiation of the drug.1 Advise females of reproductive potential to use effective contraceptive methods during therapy and for ≥3 weeks after discontinuance of the drug.1 If used during pregnancy or patient becomes pregnant, apprise of potential fetal hazard.1

Specific Populations

Pregnancy

May cause fetal harm; embryotoxic and fetotoxic in animals.1 Test for pregnancy prior to initiation of the drug.1 If used during pregnancy or patient becomes pregnant, apprise of potential fetal hazard.1

Lactation

Not known whether anastrozole or its metabolites are distributed into human milk; effects on nursing infant and milk production also unknown.1 Discontinue nursing during therapy and for 2 weeks after drug discontinuance.1

Females of Reproductive Potential

May cause fetal harm; embryotoxic, fetotoxic, and abortifacient in animals.1 Perform pregnancy test prior to initiation of anastrozole therapy in females of reproductive potential and advise such patients to use effective contraceptive methods during therapy and for ≥3 weeks after discontinuance of the drug.1

Impairment of fertility and effects on the reproductive organs demonstrated in animal studies.1

Pediatric Use

Has been used in clinical studies of adolescent boys 11–18 years of age with pubertal gynecomastia† and in girls 2 to <10 years of age with McCune-Albright syndrome and progressive precocious puberty†; however, efficacy not established for these indications.1

Geriatric Use

For adjuvant treatment of hormone receptor-positive early-stage breast cancer, efficacy (e.g., disease-free survival benefit) in women ≥65 years of age was less than efficacy observed in postmenopausal women <65 years of age.1

No substantial differences in efficacy for patients ≥65 years of age relative to younger adults when used as second line therapy for advanced breast cancer;1 moderately greater efficacy observed for patients ≥65 years of age when used as first-line therapy for locally advanced or metastatic breast cancer.1

Hepatic Impairment

Not studied in patients with severe hepatic impairment.1 No dosage adjustment required in patients with mild to moderate hepatic impairment or stable hepatic cirrhosis.1

Renal Impairment

Total body clearance of anastrozole reduced by only 10% in patients with severe renal impairment; adjustment of anastrozole dosage not required in patients with renal impairment.1

Common Adverse Effects

Early breast cancer (≥10%): hot flashes, asthenia, arthritis, pain, arthralgia, pharyngitis, hypertension, depression, nausea, vomiting, rash, osteoporosis, fractures, back pain, insomnia, headache, peripheral edema, and lymphedema.1

Advanced breast cancer (≥10%): hot flashes, nausea, asthenia, pain, headache, back pain, bone pain, increased cough, dyspnea, pharyngitis, and peripheral edema.1

Drug Interactions

Inhibits CYP1A2, 2C8/9, and 3A4 in vitro, but only at relatively high concentrations.1 Does not inhibit CYP2A6 or CYP2D6 in vitro.1 Pharmacokinetic interaction unlikely with drugs metabolized by CYP isoenzymes at recommended dosages.1

Specific Drugs

Drug

Interaction

Comment

Antipyrine

Pharmacokinetic interaction unlikely1

Estrogens

Antagonistic pharmacologic effects1

Concomitant use not recommended1

Tamoxifen

Possible decreased plasma anastrozole concentrations;1 26 concomitant use does not improve efficacy1

Concomitant use not recommended1

Warfarin

No clinically important effects on anticoagulant activity or pharmacokinetics of warfarin1
Anastrozole drug interactions (more detail)

Anastrozole Pharmacokinetics

Absorption

Bioavailability

Rapidly and well absorbed after oral administration, with peak plasma concentrations usually attained within 2 hours under fasting conditions.1

Steady-state plasma concentrations achieved in about 7 days.1

Onset

Serum estradiol concentrations reduced by approximately 70% within 24 hours of a 1-mg dose1 and by approximately 80% after 14 days of daily dosing.1

Duration

Suppression of serum estradiol concentrations maintained for up to 6 days after discontinuance of daily anastrozole administration.1

Food

Food reduces rate but does not affect extent of absorption.1

Distribution

Extent

Anastrozole crosses the placenta in animals;1 not known whether anastrozole crosses the placenta in humans.1

Not known whether anastrozole is distributed into milk.1

Plasma Protein Binding

40%.1

Elimination

Metabolism

Undergoes N-dealkylation, hydroxylation, and glucuronidation in the liver to multiple, pharmacologically inactive, metabolites.1

Elimination Route

Hepatic metabolism (85%) and renal excretion (10%).1

Half-life

Approximately 50 hours.1

Special Populations

No evidence of altered pharmacokinetics observed in women >80 years of age compared with women <50 years of age.1

Individuals with severe renal impairment (Clcr <30 mL/minute): Renal clearance decreased by approximately 50%, but total body clearance decreased by only 10%.1

Individuals with stable hepatic cirrhosis (related to alcohol abuse): Clearance reduced by approximately 30% compared with those with normal hepatic function;1 however, plasma concentrations within range compared with individuals with normal hepatic function.1

Stability

Storage

Oral

Tablets

20–25°C.1

Actions

Advice to Patients

Additional Information

The American Society of Health-System Pharmacists, Inc. represents that the information provided in the accompanying monograph was formulated with a reasonable standard of care, and in conformity with professional standards in the field. Readers are advised that decisions regarding use of drugs are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and that the information contained in the monograph is provided for informational purposes only. The manufacturer’s labeling should be consulted for more detailed information. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information contained in the monograph is not a substitute for medical care.

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Anastrozole

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Oral

Tablets, film-coated

1 mg*

Anastrozole Film-coated Tablets

Arimidex

ANI

AHFS DI Essentials™. © Copyright 2024, Selected Revisions May 22, 2023. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

† Off-label: Use is not currently included in the labeling approved by the US Food and Drug Administration.

References

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2. Jonat W, Howell A, Blomqvist C et al for the Arimidex Study Group. A randomised trial comparing two doses of the new selective aromatase inhibitor anastrozole (Arimidex) with megestrol acetate in postmenopausal patients with advanced breast cancer. Eur J Cancer. 1996; 32A:404-12. http://www.ncbi.nlm.nih.gov/pubmed/8814682?dopt=AbstractPlus

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8. Buzdar AU, Jones SE, Vogel CL et al. A phase III trial comparing anastrozole (1 and 10 milligrams), a potent and selective aromatase inhibitor, with megestrol acetate in postmenopausal women with advanced breast carcinoma. Cancer. 1997; 79:730-9. http://www.ncbi.nlm.nih.gov/pubmed/9024711?dopt=AbstractPlus

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16. Ibrahim NK, Buzdar AU. Aromatase inhibitors: current status. Am J Clin Oncol. 1995; 18:407-17. http://www.ncbi.nlm.nih.gov/pubmed/7572758?dopt=AbstractPlus

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21. Bonneterre J, Thurlimann B, Robertson JFR et al. Anastrozole versus tamoxifen as first-line therapy for advanced breast cancer in 668 postmenopausal women: results of the Tamoxifen or Arimidex Randomized Group Efficacy and Tolerability study. J Clin Oncol. 2000; 18:3748-57. http://www.ncbi.nlm.nih.gov/pubmed/11078487?dopt=AbstractPlus

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26. The ATAC Trialists’ Group. Pharmacokinetics of anastrozole and tamoxifen alone, and in combination, during adjuvant endocrine therapy for early breast cancer in postmenopausal women: a sub-protocol of the ‘ArimidexTM and Tamoxifen Alone or in Combination’ (ATAC) trial. Br J Cancer. 2001; 85:317-24. http://www.ncbi.nlm.nih.gov/pubmed/11487258?dopt=AbstractPlus http://www.pubmedcentral.nih.gov/picrender.fcgi?tool=pmcentrez&artid=2364083&blobtype=pdf

40. Bagley CM Jr, Rowbotham RK. Is anastrozole superior to tamoxifen as first-line therapy for advanced breast cancer? J Clin Oncol. 2001; 19:2578-9. Letter.

43. Eastell R, Adams JE, Coleman RE et al. Effect of anastrozole on bone mineral density: 5-year results from the anastrozole, tamoxifen, alone or in combination trial 18233230. J Clin Oncol. 2008; 26:1051-8. http://www.ncbi.nlm.nih.gov/pubmed/18309940?dopt=AbstractPlus

48. Food and Drug Administration. MedWatch—Safety-related drug labeling changes: Arimidex (anastrozole tablets) [Aug 2004]. From FDA web site. http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm152982.htm

50. Howell A, Cuzick J, Baum M. Results of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial after completion of 5 years’ adjuvant treatment for breast cancer.. Lancet. 2005; 365:60. http://www.ncbi.nlm.nih.gov/pubmed/15639680?dopt=AbstractPlus

51. Boccardo F, Rubagotti A, Puntoni M. Switching to anastrozole versus continued tamoxifen treatment of early breast cancer: preliminary results of the Italian Tamoxifen Anastrozole Trial.. J Clin Oncol. 2005; 23:5138. http://www.ncbi.nlm.nih.gov/pubmed/16009955?dopt=AbstractPlus

52. Jakesz R, Jonat W, Gnant M. Switching of postmenopausal women with endocrine-responsive early breast cancer to anastrozole after 2 years’ adjuvant tamoxifen: combined results of ABCSG trial 8 and ARNO 95 trial.. Lancet. 2005; 366:455. http://www.ncbi.nlm.nih.gov/pubmed/16084253?dopt=AbstractPlus

53. Jonat W, Gnant M, Boccardo F. Effectiveness of switching from adjuvant tamoxifen to anastrozole in postmenopausal women with hormone-sensitive early-stage breast cancer: a meta-analysis.. Lancet Oncol. 2006; 7:991. http://www.ncbi.nlm.nih.gov/pubmed/17138220?dopt=AbstractPlus

54. Jakesz R, Greil R, Gnant M. Extended adjuvant therapy with anastrozole among postmenopausal breast cancer patients: results from the randomized Austrian Breast and Colorectal Cancer Study Group Trial 6a.. J Natl Cancer Inst. 2007; 99:1845. http://www.ncbi.nlm.nih.gov/pubmed/18073378?dopt=AbstractPlus

55. Nabholtz JM, Bonneterre J, Buzdar A, Robertson JF, Thürlimann B. Anastrozole (Arimidex) versus tamoxifen as first-line therapy for advanced breast cancer in postmenopausal women: survival analysis and updated safety results.. Eur J Cancer. 2003; 39:1684. http://www.ncbi.nlm.nih.gov/pubmed/12888362?dopt=AbstractPlus

56. Mauri D, Pavlidis N, Polyzos NP, Ioannidis JP. Survival with aromatase inhibitors and inactivators versus standard hormonal therapy in advanced breast cancer: meta-analysis.. J Natl Cancer Inst. 2006; 98:1285. http://www.ncbi.nlm.nih.gov/pubmed/16985247?dopt=AbstractPlus

57. Fallowfield L, Cella D, Cuzick J, Francis S, Locker G, Howell A. Quality of life of postmenopausal women in the Arimidex, Tamoxifen, Alone or in Combination (ATAC) Adjuvant Breast Cancer Trial.. J Clin Oncol. 2004; 22:4261. http://www.ncbi.nlm.nih.gov/pubmed/15514369?dopt=AbstractPlus

63. Boccardo FRubagotti AGuglielmini PSwitching to anastrozole versus continued tamoxifen treatment of early breast cancer. Updated results of the Italian tamoxifen anastrozole (ITA) trialAnn Oncol200617 Suppl 7vii10-4

64. Dubsky PC, Jakesz R, Mlineritsch B et al. Tamoxifen and anastrozole as a sequencing strategy: a randomized controlled trial in postmenopausal patients with endocrine-responsive early breast cancer from the Austrian Breast and Colorectal Cancer Study Group. J Clin Oncol. 2012; 30:722-8. http://www.ncbi.nlm.nih.gov/pubmed/22271481?dopt=AbstractPlus

65. Kaufmann M, Jonat W, Hilfrich J et al. Improved overall survival in postmenopausal women with early breast cancer after anastrozole initiated after treatment with tamoxifen compared with continued tamoxifen: the ARNO 95 Study. J Clin Oncol. 2007; 25:2664-70. http://www.ncbi.nlm.nih.gov/pubmed/17563395?dopt=AbstractPlus

66. Cuzick J, Sestak I, Baum M et al. Effect of anastrozole and tamoxifen as adjuvant treatment for early-stage breast cancer: 10-year analysis of the ATAC trial. Lancet Oncol. 2010; 11:1135-41. http://www.ncbi.nlm.nih.gov/pubmed/21087898?dopt=AbstractPlus

68. Cella D, Fallowfield L, Barker P et al. Quality of life of postmenopausal women in the ATAC (“Arimidex”, tamoxifen, alone or in combination) trial after completion of 5 years' adjuvant treatment for early breast cancer. Breast Cancer Res Treat. 2006; 100:273-84. http://www.ncbi.nlm.nih.gov/pubmed/16944295?dopt=AbstractPlus

75. Gnant M, Fitzal F, Rinnerthaler G, et al. Duration of Adjuvant Aromatase-Inhibitor Therapy in Postmenopausal Breast Cancer. N Engl J Med. 2021;385(5):395-405.

76. Robertson JFR, Bondarenko IM, Trishkina E, et al. Fulvestrant 500 mg versus anastrozole 1 mg for hormone receptor-positive advanced breast cancer (FALCON): an international, randomised, double-blind, phase 3 trial. Lancet. 2016;388(10063):2997-3005.

77. Cuzick J, Sestak I, Forbes JF, et al. Anastrozole for prevention of breast cancer in high-risk postmenopausal women (IBIS-II): an international, double-blind, randomised placebo-controlled trial. Lancet. 2014;383(9922):1041-1048.

78. Boccardo F, Guglielmini P, Bordonaro R, et al. Switching to anastrozole versus continued tamoxifen treatment of early breast cancer: long term results of the Italian Tamoxifen Anastrozole trial. Eur J Cancer. 2013;49(7):1546-1554.

79. Gnant M, Mlineritsch B, Schippinger W, et al. Endocrine therapy plus zoledronic acid in premenopausal breast cancer. N Engl J Med. 2009;360(7):679-691.

80. Cuzick J, Sestak I, Forbes JF, et al. Use of anastrozole for breast cancer prevention (IBIS-II): long-term results of a randomised controlled trial. Lancet. 2020;395(10218):117-122. 2009;360(7):679-691.

81. Tjan-Heijnen VCG, van Hellemond IEG, Peer PGM, et al. Extended adjuvant aromatase inhibition after sequential endocrine therapy (DATA): a randomised, phase 3 trial. Lancet Oncol. 2017;18(11):1502-1511.

82. Robertson JF, Osborne CK, Howell A, et al. Fulvestrant versus anastrozole for the treatment of advanced breast carcinoma in postmenopausal women: a prospective combined analysis of two multicenter trials. Cancer. 2003;98(2):229-238.

83. Howell A, Pippen J, Elledge RM, et al. Fulvestrant versus anastrozole for the treatment of advanced breast carcinoma: a prospectively planned combined survival analysis of two multicenter trials. Cancer. 2005;104(2):236-239.

84. Rose C, Vtoraya O, Pluzanska A, et al. An open randomised trial of second-line endocrine therapy in advanced breast cancer. comparison of the aromatase inhibitors letrozole and anastrozole. Eur J Cancer. 2003;39(16):2318-2327.

4000. Burstein HJ, Somerfield MR, Barton DL, et al. Endocrine treatment and targeted therapy for hormone receptor-positive, human epidermal growth factor receptor 2-negative metastatic breast cancer: ASCO guideline update. J Clin Oncol. 2021;39(35):3959-3977.

10002. Goss PE, Ingle JN, Pritchard KI et al. Exemestane versus anastrozole in postmenopausal women with early breast cancer: NCIC CTG MA.27--a randomized controlled phase III trial. J Clin Oncol. 2013; 31:1398-404. http://www.ncbi.nlm.nih.gov/pubmed/23358971?dopt=AbstractPlus http://www.pubmedcentral.nih.gov/picrender.fcgi?tool=pmcentrez&artid=3612593&blobtype=pdf

10010. Francis PA, Regan MM, Fleming GF et al. Adjuvant ovarian suppression in premenopausal breast cancer. N Engl J Med. 2015; 372:436-46. http://www.ncbi.nlm.nih.gov/pubmed/25495490?dopt=AbstractPlus

10011. Pagani O, Regan MM, Walley BA et al. Adjuvant exemestane with ovarian suppression in premenopausal breast cancer. N Engl J Med. 2014; 371:107-18. http://www.ncbi.nlm.nih.gov/pubmed/24881463?dopt=AbstractPlus

10012. Francis PA, Pagani O, Fleming GF et al. Tailoring Adjuvant Endocrine Therapy for Premenopausal Breast Cancer. N Engl J Med. 2018; 379:122-137. http://www.ncbi.nlm.nih.gov/pubmed/29863451?dopt=AbstractPlus

10013. Tevaarwerk AJ, Wang M, Zhao F et al. Phase III comparison of tamoxifen versus tamoxifen plus ovarian function suppression in premenopausal women with node-negative, hormone receptor-positive breast cancer (E-3193, INT-0142): a trial of the Eastern Cooperative Oncology Group. J Clin Oncol. 2014; 32:3948-58. http://www.ncbi.nlm.nih.gov/pubmed/25349302?dopt=AbstractPlus

10016. Pan K, Bosserman LD, Chlebowski RT. Ovarian Suppression in Adjuvant Endocrine Therapy for Premenopausal Breast Cancer. J Clin Oncol. 2019; 37:858-861. http://www.ncbi.nlm.nih.gov/pubmed/30742565?dopt=AbstractPlus

10017. Burstein HJ, Lacchetti C, Anderson H et al. Adjuvant Endocrine Therapy for Women With Hormone Receptor-Positive Breast Cancer: American Society of Clinical Oncology Clinical Practice Guideline Update on Ovarian Suppression. J Clin Oncol. 2016; 34:1689-701. http://www.ncbi.nlm.nih.gov/pubmed/26884586?dopt=AbstractPlus

10019. Burstein HJ, Lacchetti C, Anderson H et al. Adjuvant Endocrine Therapy for Women With Hormone Receptor-Positive Breast Cancer: ASCO Clinical Practice Guideline Focused Update. J Clin Oncol. 2019; 37:423-438. http://www.ncbi.nlm.nih.gov/pubmed/30452337?dopt=AbstractPlus

10020. Dowsett M, Lønning PE, Davidson NE. Incomplete Estrogen Suppression With Gonadotropin-Releasing Hormone Agonists May Reduce Clinical Efficacy in Premenopausal Women With Early Breast Cancer. J Clin Oncol. 2016; 34:1580-3. http://www.ncbi.nlm.nih.gov/pubmed/26729430?dopt=AbstractPlus

10023. Gnant M, Mlineritsch B, Stoeger H et al. Adjuvant endocrine therapy plus zoledronic acid in premenopausal women with early-stage breast cancer: 62-month follow-up from the ABCSG-12 randomised trial. Lancet Oncol. 2011; 12:631-41. http://www.ncbi.nlm.nih.gov/pubmed/21641868?dopt=AbstractPlus

10024. Gnant M, Mlineritsch B, Stoeger H et al. Zoledronic acid combined with adjuvant endocrine therapy of tamoxifen versus anastrozol plus ovarian function suppression in premenopausal early breast cancer: final analysis of the Austrian Breast and Colorectal Cancer Study Group Trial 12. Ann Oncol. 2015; 26:313-20. http://www.ncbi.nlm.nih.gov/pubmed/25403582?dopt=AbstractPlus

10025. Bellet M, Gray KP, Francis PA et al. Twelve-Month Estrogen Levels in Premenopausal Women With Hormone Receptor-Positive Breast Cancer Receiving Adjuvant Triptorelin Plus Exemestane or Tamoxifen in the Suppression of Ovarian Function Trial (SOFT): The SOFT-EST Substudy. J Clin Oncol. 2016; 34:1584-93. http://www.ncbi.nlm.nih.gov/pubmed/26729437?dopt=AbstractPlus

10026. Perrone F, De Laurentiis M, De Placido S et al. Adjuvant zoledronic acid and letrozole plus ovarian function suppression in premenopausal breast cancer: HOBOE phase 3 randomised trial. Eur J Cancer. 2019; 118:178-186. http://www.ncbi.nlm.nih.gov/pubmed/31164265?dopt=AbstractPlus

10027. Chlebowski RT, Pan K, Col NF. Ovarian suppression in combination endocrine adjuvant therapy in premenopausal women with early breast cancer. Breast Cancer Res Treat. 2017; 161:185-190. http://www.ncbi.nlm.nih.gov/pubmed/27785653?dopt=AbstractPlus

10028. AHFS final determination of medical acceptance: Off-label use of endocrine therapy in combination with ovarian suppression for the adjuvant treatment of early-stage hormone receptor-positive breast cancer in premenopausal women. Published January 4, 2021.

10029. Smith I, Yardley D, Burris H. Comparative Efficacy and Safety of Adjuvant Letrozole Versus Anastrozole in Postmenopausal Patients With Hormone Receptor-Positive, Node-Positive Early Breast Cancer: Final Results of the Randomized Phase III Femara Versus Anastrozole Clinical Evaluation (FACE) Trial.. J Clin Oncol. 2017; 35:1041. http://www.ncbi.nlm.nih.gov/pubmed/28113032?dopt=AbstractPlus

10050. Visvanathan K, Fabian CJ, Bantug E. Use of endocrine therapy for breast cancer risk reduction: ASCO Clinical Practice Guideline update.. J Clin Oncol. 2019; 37:3152. http://www.ncbi.nlm.nih.gov/pubmed/31479306?dopt=AbstractPlus

10053. De Placido S, Gallo C, De Laurentiis M. Adjuvant anastrozole versus exemestane versus letrozole, upfront or after 2 years of tamoxifen, in endocrine-sensitive breast cancer (FATA-GIM3): a randomised, phase 3 trial.. Lancet Oncol. 2018; 19:474. http://www.ncbi.nlm.nih.gov/pubmed/29482983?dopt=AbstractPlus

10055. Nelson HD, Fu R, Zakher B, Pappas M, McDonagh M. Medication use for the risk reduction of primary breast cancer in women. Updated evidence report and systematic review for US Preventive Services Task Force.. JAMA. 2019; 322:868. http://www.ncbi.nlm.nih.gov/pubmed/31479143?dopt=AbstractPlus

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