Aromatase Inhibitors to Prevent Breast Cancer Recurrence

Table of ContentsView AllTable of ContentsHow They WorkIndicationsDosageSide EffectsInteractionsContraindicationsOngoing Research

Table of ContentsView All

View All

Table of Contents

How They Work

Indications

Dosage

Side Effects

Interactions

Contraindications

Ongoing Research

Aromatase inhibitors are a class of drug used to preventcancer recurrencein postmenopausal women withestrogen receptor-positive breast cancer. These medications also are prescribed for premenopausal women in combination with ovarian suppression therapy and for men with breast cancer who are unable to take tamoxifen.

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Woman taking vitamins and supplements

For women with breast cancer, there is growing evidence aromatase inhibitors are more effective than tamoxifen, the drug traditionally used to prevent breast cancer recurrence. In addition, clinical research is pointing to a day where aromatase inhibitors may be used to prevent breast cancer in postmenopausal women who are at an increased risk of the disease.

Despite these benefits, aromatase inhibitors can cause significant side effects, including accelerated bone loss leading toosteoporosis.

In women who have not undergonemenopause, estrogen is produced mainly in theovariesand, to a lesser degree, in peripheral tissues such as the breasts, liver, brain, skin, bone, and pancreas. In postmenopausal women, whose ovaries are no longer functioning, the peripheral tissues are the predominant source of estrogen.

Aromatase inhibitors block a process that occurs within these cells called aromatization—the conversion of the male hormonetestosteroneintoestrone and estradiol(the two primary forms of estrogen) via an enzyme known as aromatase.

Aromatase inhibitors differ from tamoxifen in that tamoxifen binds to estrogen receptors on cells rather than to aromatase. The different mechanisms of action achieve similar outcomes, but with different rates of efficacy.

Aromatase inhibitors are approved to reduce the risk of recurrence in postmenopausal women with estrogen receptor-positive breast cancer.They can also be used to treat advanced breast cancer, includingstage 4 breast cancer, in which the malignancy has spread (metastasized) to other parts of the body.

For men with breast cancer, the 2020 American Society of Clinical Oncology Guidelines recommend tamoxifen be used instead of an aromatase inhibitor to reduce the risk of breast cancer recurrence. An aromatase inhibitor (in combination with ovarian suppression therapy) may be considered, however, for men who are unable to take tamoxifen for some reason.

Each individual aromatase inhibitor has its own specific indications.

Arimidexis indicated for use as:

Aromasinis indicated for use as:

Femarais indicated for use as:

Aromatase inhibitor treatment is started after primary treatment is complete. This includesbreast cancer surgeryand possiblychemotherapy. Treatment with aromatase inhibitors can be started at the same time withradiation therapy.

How Premenopausal Breast Cancer Is Different

Reduction of Late Recurrence

In people who have estrogen receptor positive tumors, the risk of recurrence does not decrease with time. In fact, a hormone positive early stage breast cancer is more likely to recurafterfive years than in the first five years. It’s thought that the risk of recurrence remains steady (the same chance of recurrence each year) for at least 20 years following the original diagnosis. Fortunately, while chemotherapy does not appear to significantly reduce the risk of late recurrence, hormonal therapy (such as aromatase inhibitors) can reduce the risk.

Late Recurrence of Breast Cancer

Aromatase inhibitors are delivered in tablet form and prescribed as a once-daily dose. Arimidex and Femara can be taken with or without food. Aromasin should be taken after a meal as fat in food aids in the drug’s absorption.

As with any medication, aromatase inhibitors can cause side effects and adverse reactions. Some of the more common ones are related to the reduction of estrogen in the body, leading tomenopausal symptomsand other more potentially serious complications.

The common short-term side effects associated with all three aromatase inhibitors include:

Of these, persistent joint and muscle pain are the commonly cited reasons for treatment termination. Hot flashes are the most frequent side effect, impacting as many as 59% of women on aromatase inhibitors, according to a 2014 study inCancer.

Hot Flashes Linked to Breast Cancer Survival

Osteoporosis Risk

The long-term effects of aromatase inhibitors are arguably more concerning. Unlike tamoxifen, aromatase inhibitors tend to speed uposteopenia(bone loss) in older women who are already at risk of bone problems.

Women on aromatase inhibitors are at a two- and four-fold increased risk of bone loss compared to a matched set of women in the general population, says a 2015 review in theJournal of Bone Oncology.

After five years of use, an estimated one of out of every 10 women on aromatase inhibitors will experience a fracture due to drug-induced osteoporosis.

Treatment with tamoxifen for two to five years before aromatase inhibitors may slow down the rate of bone loss. Similarly,bisphosphonate drugslike Zometa (zoledronic acid) may help counteract osteopenia, though they increase the risk ofosteonecrosisof the jaw.

Other Complications

Aromatase inhibitors are also associated with an increased risk of cardiovascular disorders, includinghyperlipidemia(high cholesterol),arrhythmia(abnormal heart rhythm),heart valve problems, andpericarditis(inflammation of the membranes around the heart).With that being said, serious or life-threatening cardiovascular events, such as heart attacks or stroke, are no more common in women who take aromatase inhibitors than those who don’t.

A 2018 study in theJournal of Clinical Oncologyalso noted that the risk of diabetes was 240% greater in women on aromatase inhibitors than in the general population.Although the risk was far lower with tamoxifen, aromatase inhibitors do not pose the risk ofthromboembolism(blood clots) orendometrial cancerthat tamoxifen does.

Benefits of Tamoxifen vs. Aromatase Inhibitors

Aromatase inhibitors can interact with certain medications. Some interactions may decrease the concentration of the aromatase inhibitor in the blood and require a dose adjustment to compensate for the effect.

Among the commonly cited drug interactions:

Advise your oncologist about any medications you are taking, whether they are pharmaceutical, over-the-counter, recreational, or traditional to avoid drug interactions.

Aromatase inhibitors should not be used in people with a known hypersensitivity to any of the active or inactive ingredients in the drug. With that being said, a drug allergy is not common with aromatase inhibitors, affecting less than one out of 10,000 users.

Armidex, Aromasin, and Femara can cause fetal harm and should not be used if there is any chance of pregnancy.As a safeguard, pregnancy testing is recommended seven days prior to the start of treatment if a woman’s menopausal status is unknown.

There is growing evidence that aromatase may benefit more than just postmenopausal women. A number of studies shown that the drugs may be beneficial in premenopausal women whose ovaries have suppressed withgonadotropin-releasing hormone agonists (GnHRa).

A 2015 study in theNew England Journal of Medicinereported that the use of Aromasin in women on ovary suppression therapy was just as effective in preventing recurrence after five years as tamoxifen.Similar results have been seen with Arimidex and Femara.

Even more impressive, a number of clinical studies have suggested that aromatase inhibitors may be just as effective in preventing breast cancer as preventing breast cancer recurrence.

Although the FDA has not yet approved aromatase inhibitors for any of these purposes, many believe that supporting research will one day broaden the current treatment recommendations.

Reducing the Risk of Breast Cancer Recurrence

15 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.U.S. National Library of Medicine. MedlinePlus.Hormone therapy for breast cancer.Miller WR, Larionov AA.Understanding the mechanisms of aromatase inhibitor resistance.Breast Cancer Res. 2012;14(1):201. doi:10.1186/bcr2931Early Breast Cancer Trialists' Collaborative Group (EBCTCG).Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials.Lancet.2015;386(10001):1341-1352. doi:10.1016/S0140-6736(15)61074-1Breastcancer.org.Aromatase inhibitors.Hassett MJ, Somerfield MR, Baker ER, et al.Management of male breast cancer: ASCO guideline.J Clin Oncol.2020;38(16):1849-1863. doi:10.1200/JCO.19.03120U.S. National Library of Medicine. ARIMIDEX.Highlights of prescribing information.Aromasin.Highlights of prescribing information.Femara.Highlights of prescribing information.Pan H, Gray R, Braybrooke, J, et al.20-year risks of breast-cancer recurrence after stopping endocrine therapy at 5 years.N Engl J Med. 2017;377:1836-1846. doi:10.1056/NEJMoa1701830Bao T, Cai L, Snyder C, et al.Patient-reported outcomes in women with breast cancer enrolled in a dual-center, double-blind, randomized controlled trial assessing the effect of acupuncture in reducing aromatase inhibitor-induced musculoskeletal symptoms.Cancer. 2014;120(3):381-9. doi:10.1002/cncr.28352Hadji P, Aapro MS, Body JJ, et al.Management of aromatase inhibitor-associated bone loss (AIBL) in postmenopausal women with hormone sensitive breast cancer: Joint position statement of the IOF, CABS, ECTS, IEG, ESCEO IMS, and SIOG.J Bone Oncol. 2017;7:1-12. doi:+10.1016/j.jbo.2017.03.001Haque R, Shi J, Schottinger JE, et al.Cardiovascular disease after aromatase inhibitor use.JAMA Oncol. 2016;2(12):1590-1597. doi:10.1001/jamaoncol.2016.0429Hamood R, Hamood H, Merhasin I, Keinan-boker L.Diabetes after hormone therapy in breast cancer survivors: A case-cohort study.J Clin Oncol. 2018;36(20):2061-2069. doi:10.1200/JCO.2017.76.3524Francis PA, Regan MM, Fleming GF, et al.Adjuvant ovarian suppression in premenopausal breast cancer.N Engl J Med. 2015;372(5):436-46. doi:10.1056/NEJMoa1412379Cuzick 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. doi:10.1016/S0140-6736(19)32955-1Additional ReadingBao T, Cai L, Snyder C, et al.Patient-reported outcomes in women with breast cancer enrolled in a dual-center, double-blind, randomized controlled trial assessing the effect of acupuncture in reducing aromatase inhibitor-induced musculoskeletal symptoms: Acupuncture & Patient-Reported Outcomes.Cancer. 2014;120(3):381-389. doi:10.1002/cncr.28352Cuzick J, Sestak I, Forbes JF, et al.Anastrozole for prevention of breast cancer in high-risk postmenopausal women (IBIS-II): an international, double-blind randomized placebo-controlled trial.Lancet.2014;383(9922):1041-8. doi:10.1016/S0140-6736(13)62292-8Cuzick 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. doi:10.1016/S0140-6736(19)32955-1Early Breast Cancer Trialists' Collaborative Group (EBCTCG).Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials.Lancet.2015;386(10001):1341-52. doi:10.1016/S0140-6736(15)61074-1Early Breast Cancer Trialists' Collaborative Group (EBCTCG).Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials.Lancet.2015;386(10001):1341-1352. doi:10.1016/S0140-6736(15)61074-1Francis PA, Regan MM, Fleming GF, et al.Adjuvant ovarian suppression in premenopausal breast cancer.New Engl J Med.2015;372(5):436-44. doi:10.1056/nejmoa1412379Hadji P, Aapro MS, Body J-J, et al.Management of aromatase inhibitor-associated bone loss (AIBL) in postmenopausal women with hormone-sensitive breast cancer: Joint position statement of the IOF, CABS, ECTS, IEG, ESCEO, IMS, and SIOG.J Bone Oncol.2017;7:1-12. doi:10.1016/j.jbo.2017.03.001Pan H, Gray R, Braybrooke, J, et al.20-year risks of breast-cancer recurrence after stopping endocrine therapy at 5 years.The N Engl J Med. 2017;377:1836-1846. doi:10.1056/NEJMoa1701830U.S. Food and Drug Administration.Highlights of prescribing information: Arimidex (anastrozole).U.S. Food and Drug Administration.Highlights of Prescribing Information: Femara (letrozole).U.S. Food and Drug Administration.Highlights of prescribing information: Aromasin (exemestane).

15 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.U.S. National Library of Medicine. MedlinePlus.Hormone therapy for breast cancer.Miller WR, Larionov AA.Understanding the mechanisms of aromatase inhibitor resistance.Breast Cancer Res. 2012;14(1):201. doi:10.1186/bcr2931Early Breast Cancer Trialists' Collaborative Group (EBCTCG).Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials.Lancet.2015;386(10001):1341-1352. doi:10.1016/S0140-6736(15)61074-1Breastcancer.org.Aromatase inhibitors.Hassett MJ, Somerfield MR, Baker ER, et al.Management of male breast cancer: ASCO guideline.J Clin Oncol.2020;38(16):1849-1863. doi:10.1200/JCO.19.03120U.S. National Library of Medicine. ARIMIDEX.Highlights of prescribing information.Aromasin.Highlights of prescribing information.Femara.Highlights of prescribing information.Pan H, Gray R, Braybrooke, J, et al.20-year risks of breast-cancer recurrence after stopping endocrine therapy at 5 years.N Engl J Med. 2017;377:1836-1846. doi:10.1056/NEJMoa1701830Bao T, Cai L, Snyder C, et al.Patient-reported outcomes in women with breast cancer enrolled in a dual-center, double-blind, randomized controlled trial assessing the effect of acupuncture in reducing aromatase inhibitor-induced musculoskeletal symptoms.Cancer. 2014;120(3):381-9. doi:10.1002/cncr.28352Hadji P, Aapro MS, Body JJ, et al.Management of aromatase inhibitor-associated bone loss (AIBL) in postmenopausal women with hormone sensitive breast cancer: Joint position statement of the IOF, CABS, ECTS, IEG, ESCEO IMS, and SIOG.J Bone Oncol. 2017;7:1-12. doi:+10.1016/j.jbo.2017.03.001Haque R, Shi J, Schottinger JE, et al.Cardiovascular disease after aromatase inhibitor use.JAMA Oncol. 2016;2(12):1590-1597. doi:10.1001/jamaoncol.2016.0429Hamood R, Hamood H, Merhasin I, Keinan-boker L.Diabetes after hormone therapy in breast cancer survivors: A case-cohort study.J Clin Oncol. 2018;36(20):2061-2069. doi:10.1200/JCO.2017.76.3524Francis PA, Regan MM, Fleming GF, et al.Adjuvant ovarian suppression in premenopausal breast cancer.N Engl J Med. 2015;372(5):436-46. doi:10.1056/NEJMoa1412379Cuzick 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. doi:10.1016/S0140-6736(19)32955-1Additional ReadingBao T, Cai L, Snyder C, et al.Patient-reported outcomes in women with breast cancer enrolled in a dual-center, double-blind, randomized controlled trial assessing the effect of acupuncture in reducing aromatase inhibitor-induced musculoskeletal symptoms: Acupuncture & Patient-Reported Outcomes.Cancer. 2014;120(3):381-389. doi:10.1002/cncr.28352Cuzick J, Sestak I, Forbes JF, et al.Anastrozole for prevention of breast cancer in high-risk postmenopausal women (IBIS-II): an international, double-blind randomized placebo-controlled trial.Lancet.2014;383(9922):1041-8. doi:10.1016/S0140-6736(13)62292-8Cuzick 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. doi:10.1016/S0140-6736(19)32955-1Early Breast Cancer Trialists' Collaborative Group (EBCTCG).Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials.Lancet.2015;386(10001):1341-52. doi:10.1016/S0140-6736(15)61074-1Early Breast Cancer Trialists' Collaborative Group (EBCTCG).Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials.Lancet.2015;386(10001):1341-1352. doi:10.1016/S0140-6736(15)61074-1Francis PA, Regan MM, Fleming GF, et al.Adjuvant ovarian suppression in premenopausal breast cancer.New Engl J Med.2015;372(5):436-44. doi:10.1056/nejmoa1412379Hadji P, Aapro MS, Body J-J, et al.Management of aromatase inhibitor-associated bone loss (AIBL) in postmenopausal women with hormone-sensitive breast cancer: Joint position statement of the IOF, CABS, ECTS, IEG, ESCEO, IMS, and SIOG.J Bone Oncol.2017;7:1-12. doi:10.1016/j.jbo.2017.03.001Pan H, Gray R, Braybrooke, J, et al.20-year risks of breast-cancer recurrence after stopping endocrine therapy at 5 years.The N Engl J Med. 2017;377:1836-1846. doi:10.1056/NEJMoa1701830U.S. Food and Drug Administration.Highlights of prescribing information: Arimidex (anastrozole).U.S. Food and Drug Administration.Highlights of Prescribing Information: Femara (letrozole).U.S. Food and Drug Administration.Highlights of prescribing information: Aromasin (exemestane).

U.S. National Library of Medicine. MedlinePlus.Hormone therapy for breast cancer.Miller WR, Larionov AA.Understanding the mechanisms of aromatase inhibitor resistance.Breast Cancer Res. 2012;14(1):201. doi:10.1186/bcr2931Early Breast Cancer Trialists' Collaborative Group (EBCTCG).Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials.Lancet.2015;386(10001):1341-1352. doi:10.1016/S0140-6736(15)61074-1Breastcancer.org.Aromatase inhibitors.Hassett MJ, Somerfield MR, Baker ER, et al.Management of male breast cancer: ASCO guideline.J Clin Oncol.2020;38(16):1849-1863. doi:10.1200/JCO.19.03120U.S. National Library of Medicine. ARIMIDEX.Highlights of prescribing information.Aromasin.Highlights of prescribing information.Femara.Highlights of prescribing information.Pan H, Gray R, Braybrooke, J, et al.20-year risks of breast-cancer recurrence after stopping endocrine therapy at 5 years.N Engl J Med. 2017;377:1836-1846. doi:10.1056/NEJMoa1701830Bao T, Cai L, Snyder C, et al.Patient-reported outcomes in women with breast cancer enrolled in a dual-center, double-blind, randomized controlled trial assessing the effect of acupuncture in reducing aromatase inhibitor-induced musculoskeletal symptoms.Cancer. 2014;120(3):381-9. doi:10.1002/cncr.28352Hadji P, Aapro MS, Body JJ, et al.Management of aromatase inhibitor-associated bone loss (AIBL) in postmenopausal women with hormone sensitive breast cancer: Joint position statement of the IOF, CABS, ECTS, IEG, ESCEO IMS, and SIOG.J Bone Oncol. 2017;7:1-12. doi:+10.1016/j.jbo.2017.03.001Haque R, Shi J, Schottinger JE, et al.Cardiovascular disease after aromatase inhibitor use.JAMA Oncol. 2016;2(12):1590-1597. doi:10.1001/jamaoncol.2016.0429Hamood R, Hamood H, Merhasin I, Keinan-boker L.Diabetes after hormone therapy in breast cancer survivors: A case-cohort study.J Clin Oncol. 2018;36(20):2061-2069. doi:10.1200/JCO.2017.76.3524Francis PA, Regan MM, Fleming GF, et al.Adjuvant ovarian suppression in premenopausal breast cancer.N Engl J Med. 2015;372(5):436-46. doi:10.1056/NEJMoa1412379Cuzick 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. doi:10.1016/S0140-6736(19)32955-1

U.S. National Library of Medicine. MedlinePlus.Hormone therapy for breast cancer.

Miller WR, Larionov AA.Understanding the mechanisms of aromatase inhibitor resistance.Breast Cancer Res. 2012;14(1):201. doi:10.1186/bcr2931

Early Breast Cancer Trialists' Collaborative Group (EBCTCG).Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials.Lancet.2015;386(10001):1341-1352. doi:10.1016/S0140-6736(15)61074-1

Breastcancer.org.Aromatase inhibitors.

Hassett MJ, Somerfield MR, Baker ER, et al.Management of male breast cancer: ASCO guideline.J Clin Oncol.2020;38(16):1849-1863. doi:10.1200/JCO.19.03120

U.S. National Library of Medicine. ARIMIDEX.Highlights of prescribing information.

Aromasin.Highlights of prescribing information.

Femara.Highlights of prescribing information.

Pan H, Gray R, Braybrooke, J, et al.20-year risks of breast-cancer recurrence after stopping endocrine therapy at 5 years.N Engl J Med. 2017;377:1836-1846. doi:10.1056/NEJMoa1701830

Hadji P, Aapro MS, Body JJ, et al.Management of aromatase inhibitor-associated bone loss (AIBL) in postmenopausal women with hormone sensitive breast cancer: Joint position statement of the IOF, CABS, ECTS, IEG, ESCEO IMS, and SIOG.J Bone Oncol. 2017;7:1-12. doi:+10.1016/j.jbo.2017.03.001

Haque R, Shi J, Schottinger JE, et al.Cardiovascular disease after aromatase inhibitor use.JAMA Oncol. 2016;2(12):1590-1597. doi:10.1001/jamaoncol.2016.0429

Hamood R, Hamood H, Merhasin I, Keinan-boker L.Diabetes after hormone therapy in breast cancer survivors: A case-cohort study.J Clin Oncol. 2018;36(20):2061-2069. doi:10.1200/JCO.2017.76.3524

Francis PA, Regan MM, Fleming GF, et al.Adjuvant ovarian suppression in premenopausal breast cancer.N Engl J Med. 2015;372(5):436-46. doi:10.1056/NEJMoa1412379

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. doi:10.1016/S0140-6736(19)32955-1

Bao T, Cai L, Snyder C, et al.Patient-reported outcomes in women with breast cancer enrolled in a dual-center, double-blind, randomized controlled trial assessing the effect of acupuncture in reducing aromatase inhibitor-induced musculoskeletal symptoms: Acupuncture & Patient-Reported Outcomes.Cancer. 2014;120(3):381-389. doi:10.1002/cncr.28352Cuzick J, Sestak I, Forbes JF, et al.Anastrozole for prevention of breast cancer in high-risk postmenopausal women (IBIS-II): an international, double-blind randomized placebo-controlled trial.Lancet.2014;383(9922):1041-8. doi:10.1016/S0140-6736(13)62292-8Cuzick 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. doi:10.1016/S0140-6736(19)32955-1Early Breast Cancer Trialists' Collaborative Group (EBCTCG).Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials.Lancet.2015;386(10001):1341-52. doi:10.1016/S0140-6736(15)61074-1Early Breast Cancer Trialists' Collaborative Group (EBCTCG).Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials.Lancet.2015;386(10001):1341-1352. doi:10.1016/S0140-6736(15)61074-1Francis PA, Regan MM, Fleming GF, et al.Adjuvant ovarian suppression in premenopausal breast cancer.New Engl J Med.2015;372(5):436-44. doi:10.1056/nejmoa1412379Hadji P, Aapro MS, Body J-J, et al.Management of aromatase inhibitor-associated bone loss (AIBL) in postmenopausal women with hormone-sensitive breast cancer: Joint position statement of the IOF, CABS, ECTS, IEG, ESCEO, IMS, and SIOG.J Bone Oncol.2017;7:1-12. doi:10.1016/j.jbo.2017.03.001Pan H, Gray R, Braybrooke, J, et al.20-year risks of breast-cancer recurrence after stopping endocrine therapy at 5 years.The N Engl J Med. 2017;377:1836-1846. doi:10.1056/NEJMoa1701830U.S. Food and Drug Administration.Highlights of prescribing information: Arimidex (anastrozole).U.S. Food and Drug Administration.Highlights of Prescribing Information: Femara (letrozole).U.S. Food and Drug Administration.Highlights of prescribing information: Aromasin (exemestane).

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 randomized placebo-controlled trial.Lancet.2014;383(9922):1041-8. doi:10.1016/S0140-6736(13)62292-8

Francis PA, Regan MM, Fleming GF, et al.Adjuvant ovarian suppression in premenopausal breast cancer.New Engl J Med.2015;372(5):436-44. doi:10.1056/nejmoa1412379

Hadji P, Aapro MS, Body J-J, et al.Management of aromatase inhibitor-associated bone loss (AIBL) in postmenopausal women with hormone-sensitive breast cancer: Joint position statement of the IOF, CABS, ECTS, IEG, ESCEO, IMS, and SIOG.J Bone Oncol.2017;7:1-12. doi:10.1016/j.jbo.2017.03.001

Pan H, Gray R, Braybrooke, J, et al.20-year risks of breast-cancer recurrence after stopping endocrine therapy at 5 years.The N Engl J Med. 2017;377:1836-1846. doi:10.1056/NEJMoa1701830

U.S. Food and Drug Administration.Highlights of prescribing information: Arimidex (anastrozole).

U.S. Food and Drug Administration.Highlights of Prescribing Information: Femara (letrozole).

U.S. Food and Drug Administration.Highlights of prescribing information: Aromasin (exemestane).

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Reduction of Late Recurrence#

Osteoporosis Risk#

Other Complications#

Reduction of Late Recurrence

Osteoporosis Risk

Other Complications