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Why are dosages for estrogen suppression drugs one-size-fits-all?
Breast Cancer | Last Active: Apr 24 9:39pm | Replies (59)Comment receiving replies
I wanted to read this study, but the address is ‘not found’. I too was prescribed an AI and declined, due to standard protocols and dosage. I am 74, weigh 108 lbs (with partial Osteopenia) and have good health (exception BC with recent lumpectomy followed by 5day rad) My Oncologist has been outwardly upset with me and my husband for refusing any AI. At the time of my surgery and post treatment, I was given a choice, radiation or AI or both. I choice radiation. I am closely monitoring my breasts and praying no recurrence. The standard protocols call for a one-size treatment for all BC sufferers.
Replies to "I wanted to read this study, but the address is ‘not found’. I too was prescribed..."
Ellie, I am right there with you. I just got back from post BC surgeon (lumpectomy) and she was quizzing me about refusing AI drugs. 2 weeks my oncologist will do the same again. What were the specifics of your BC? Mine is HR/PR+, clear margins, Invasive Ductal Carcinoma, Grade 1, slow growing & I also chose 5 targeted radiation. treatments. I am 71 , 124 lbs, in good health & The side effects scare me to death.
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Am pasting the abstract of that article here:
. 2014 Aug;14(4):291-6. doi: 10.1016/j.clbc.2013.12.008. Epub 2013 Dec 27.
Does obesity interfere with anastrozole treatment? Positive association between body mass index and anastrozole plasma levels
Michael Hubalek 1, Anne Oberguggenberger 2, Beate Beer 3, Verena Meraner 2, Monika Sztankay 2, Herbert Oberacher 3, Birthe Schubert 3, Ludwig Wildt 4, Beata Seeber 4, Johannes Giesinger 2, Georg Kemmler 2, Bernhard Holzner 2, Barbara Sperner-Unterweger 2
Affiliations expand
PMID: 24468298 DOI: 10.1016/j.clbc.2013.12.008
Abstract
Introduction: The efficacy of adjuvant endocrine treatment with aromatase inhibitors (AIs), inhibiting the conversion of androgens to estrogen in adipose tissue, might depend on the overall volume of adipose tissue. However, little evidence is available regarding the pharmacokinetic behavior of AIs in women with obesity. The aim of this study was to investigate the interaction between body mass index (BMI) and anastrozole treatment as well as estrogenic activity.
Patients and methods: A total of 216 postmenopausal patients with early-stage breast cancer who were receiving AI treatment with anastrozole constituted the final sample included in the analysis. During a regular 3-month after-care check-up, sociodemographic and clinical data and BMI were assessed. Blood samples were collected during routine blood testing. Measurement of AI plasma levels was performed by liquid chromatography-tandem mass spectrometry. Follicle stimulating hormone (FSH) and estradiol were measured within the routine blood examination.
Results: A median anastrozole plasma concentration of 34.7 ng/mL (mean, 37.4), with a large interindividual variability, was observed (SD, 15.1; range, 5.4-86.5). After age adjustment, it was found that anastrozole plasma concentrations significantly increased with BMI (r = 0.241; P = .001). Anastrozole serum concentrations in women with obesity (BMI ≥ 30) exceeded those of women with normal weight (BMI ≤ 25) by 25%. Women with excess weight had lower mean FSH levels, indicating higher estrogenic activity, compared with women with normal weight.
Conclusion: This study indicates that BMI is a vital factor in anastrozole metabolism, as measured by anastrozole plasma concentration and FSH levels. Further research is mandatory to clarify results on the association of obesity and AI treatment efficacy to allow adapting AI treatment accordingly.