Document Detail

Suppression of plasma estrogen levels by letrozole and anastrozole is related to body mass index in patients with breast cancer.
MedLine Citation:
PMID:  22802308     Owner:  NLM     Status:  MEDLINE    
PURPOSE: To investigate whether suppression of plasma estradiol and estrone sulfate levels by the aromatase inhibitors (AIs) anastrozole and letrozole is related to body mass index (BMI) in postmenopausal women with early estrogen receptor (ER) -positive breast cancer. Recent studies have reported that the AI anastrozole has lower effectiveness than tamoxifen in women with high BMI. This effect with high BMI might hypothetically be a result of reduced inhibition of aromatase and suppression of plasma estrogen levels and might be overcome by the use of an increased dose of anastrozole or, alternatively, the use of a more potent AI such as letrozole.
PATIENTS AND METHODS: Plasma estradiol and estrone sulfate levels from a highly sensitive radioimmunoassay were available for 44 postmenopausal patients who received anastrozole (1 mg per day) for 3 months followed by letrozole (2.5 mg per day) for 3 months or the opposite sequence. Correlations between the estrogen suppression by each AI and BMI were assessed.
RESULTS: Baseline values of estradiol and estrone sulfate were significantly correlated with BMI (r = 0.57; P < .001, and r = 0.38; P = .006, respectively). Levels of estrogen in patients receiving treatment were greater at higher levels of BMI with both AIs, but although this was significant with letrozole (r = 0.35; P = .013, and r = 0.30; P = .035 for estradiol and estrone sulfate, respectively), it was not with anastrozole. Suppression of both estrogen types was greater with letrozole across the full range of BMIs in this study.
CONCLUSION: The suppressed levels of plasma estradiol and estrone sulfate in postmenopausal women with early ER-positive breast cancer treated with the AIs anastrozole and letrozole are related to BMI.
Elizabeth J Folkerd; J Michael Dixon; Lorna Renshaw; Roger P A'Hern; Mitch Dowsett
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-07-16
Journal Detail:
Title:  Journal of clinical oncology : official journal of the American Society of Clinical Oncology     Volume:  30     ISSN:  1527-7755     ISO Abbreviation:  J. Clin. Oncol.     Publication Date:  2012 Aug 
Date Detail:
Created Date:  2012-08-20     Completed Date:  2012-10-30     Revised Date:  2013-03-07    
Medline Journal Info:
Nlm Unique ID:  8309333     Medline TA:  J Clin Oncol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2977-80     Citation Subset:  IM    
Royal Marsden Hospital, London, United Kingdom.
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MeSH Terms
Aged, 80 and over
Antineoplastic Agents, Hormonal / administration & dosage,  pharmacology*
Aromatase Inhibitors / administration & dosage,  pharmacology*
Body Mass Index*
Breast Neoplasms / blood*,  drug therapy*
Estrogens / blood*
Estrone / analogs & derivatives,  blood
Middle Aged
Neoplasms, Hormone-Dependent / blood*,  drug therapy
Nitriles / administration & dosage,  pharmacology*
Triazoles / administration & dosage,  pharmacology*
Reg. No./Substance:
0/Antineoplastic Agents, Hormonal; 0/Aromatase Inhibitors; 0/Estrogens; 0/Nitriles; 0/Triazoles; 112809-51-5/letrozole; 120511-73-1/anastrozole; 53-16-7/Estrone; QTL48N278K/estrone sulfate
Comment In:
J Clin Oncol. 2012 Aug 20;30(24):2940-2   [PMID:  22802318 ]
J Clin Oncol. 2013 Feb 1;31(4):509-10
J Clin Oncol. 2013 Feb 1;31(4):509   [PMID:  23270000 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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