{"entity":{"id":"aromatase-inhibitor","kind":"term","name":"Aromatase inhibitor","aka":["aromatase inhibitors","aromatase inhibition","ovarian suppression","ovarian function suppression","OFS","extended endocrine therapy","adjuvant endocrine therapy","endocrine therapy"],"tldr":"Pills that stop the body making oestrogen (after the menopause, when it comes from fat and muscle rather than the ovaries), starving hormone receptor-positive breast cancer. Taken for five to ten years after surgery, they halve recurrence.","summary":"Letrozole, anastrozole and exemestane block the aromatase enzyme; in premenopausal women they only work with ovarian function suppression (GnRH agonist or oophorectomy, SOFT/TEXT). They modestly beat tamoxifen in postmenopausal adjuvant therapy (ATAC, BIG 1-98) and are the partner drug for CDK4/6 inhibitors in metastatic disease. Side effects are joint pain, bone loss (needing bisphosphonates), vaginal dryness and cardiovascular effects, and adherence over 5-10 years is a real problem. Resistance often comes through ESR1 mutations, which favour switching to a SERD.","asOf":"2026-09-09","wikipedia":"https://en.wikipedia.org/wiki/Aromatase_inhibitor","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Aromatase_inhibitor"}],"tags":[],"related":["hormone-receptor-status","serd","endocrine-resistance","salpingo-oophorectomy"],"cancers":["breast-hr-positive"],"sections":["hormonal"],"technologies":["endocrine-therapy","cdk46-inhibitor"],"targets":[],"drugs":["letrozole","tamoxifen"],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Treatment jargon"},"route":"/terms/aromatase-inhibitor/","neighbours":{"term":[{"id":"endocrine-resistance","kind":"term","name":"Endocrine resistance","route":"/terms/endocrine-resistance/"},{"id":"endocrine-therapy-resistance","kind":"term","name":"Endocrine therapy and endocrine resistance","route":"/terms/endocrine-therapy-resistance/"},{"id":"hormone-receptor-status","kind":"term","name":"Hormone receptor status (ER / PR)","route":"/terms/hormone-receptor-status/"},{"id":"salpingo-oophorectomy","kind":"term","name":"Salpingo-oophorectomy","route":"/terms/salpingo-oophorectomy/"},{"id":"serd","kind":"term","name":"Selective oestrogen receptor degrader (SERD)","route":"/terms/serd/"}],"cancer":[{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"lobular-carcinoma-in-situ","kind":"cancer","name":"Lobular carcinoma in situ (LCIS)","route":"/cancers/lobular-carcinoma-in-situ/"}],"section":[{"id":"hormonal","kind":"section","name":"Hormonal Therapy","route":"/fronts/hormonal/"}],"technology":[{"id":"acupuncture-aromatase-inhibitor-arthralgia","kind":"technology","name":"Acupuncture for aromatase-inhibitor joint pain","route":"/technologies/acupuncture-aromatase-inhibitor-arthralgia/"},{"id":"acupuncture-hot-flushes","kind":"technology","name":"Acupuncture for hot flushes on endocrine therapy","route":"/technologies/acupuncture-hot-flushes/"},{"id":"cancer-treatment-bone-loss","kind":"technology","name":"Bone loss caused by cancer treatment, and what rebuilds it","route":"/technologies/cancer-treatment-bone-loss/"},{"id":"cdk46-inhibitor","kind":"technology","name":"CDK4/6 inhibitors","route":"/technologies/cdk46-inhibitor/"},{"id":"endocrine-therapy","kind":"technology","name":"Endocrine therapy (SERMs, AIs, SERDs)","route":"/technologies/endocrine-therapy/"},{"id":"menopause-after-cancer-treatment","kind":"technology","name":"Menopause brought on by cancer treatment, and the options for it","route":"/technologies/menopause-after-cancer-treatment/"},{"id":"minoxidil-chemotherapy-alopecia","kind":"technology","name":"Minoxidil for persistent chemotherapy- and endocrine-therapy hair loss","route":"/technologies/minoxidil-chemotherapy-alopecia/"},{"id":"vaginal-oestrogen-after-breast-cancer","kind":"technology","name":"Vaginal oestrogen after breast cancer: what the evidence says, and where it disagrees","route":"/technologies/vaginal-oestrogen-after-breast-cancer/"}],"drug":[{"id":"letrozole","kind":"drug","name":"Letrozole (and other aromatase inhibitors)","route":"/drugs/letrozole/"},{"id":"tamoxifen","kind":"drug","name":"Tamoxifen","route":"/drugs/tamoxifen/"}]}}