Melika Shirdarreh1, Rossanna C Pezo2,3,4. 1. University of Toronto, Toronto, ON, Canada. 2. Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada. rossanna.pezo@sunnybrook.ca. 3. Department of Medicine, University of Toronto, Toronto, ON, Canada. rossanna.pezo@sunnybrook.ca. 4. Division of Medical Oncology and Hematology, Sunnybrook Odette Cancer Centre, 2075 Bayview Avenue, Toronto, ON, M4N 3N5, Canada. rossanna.pezo@sunnybrook.ca.
Abstract
BACKGROUND: The relationship between obesity and prognosis of early breast cancer is complex. Increased levels of aromatase present in adipose tissue of obese postmenopausal women may lead to suboptimal suppression of systemic estrogens. However, studies have been mixed with respect to the association between use of aromatase inhibitors (AIs) and clinical outcomes in obese women with early breast cancer. METHODS: We conducted a systematic literature review following PRISMA guidelines to examine the impact of obesity on the efficacy of AIs in early-stage hormone receptor-positive breast cancer. Primary outcome measures included disease-free survival, relapse-free survival, distant recurrence-free survival, breast cancer-free survival, and overall survival. RESULTS: Of 491 studies identified, eight studies met criteria for inclusion: three retrospective cohort studies, one prospective cohort study and four randomized controlled trials. Four studies limited eligibility to postmenopausal women. Percentage of obese patients in studies ranged from 10 to 30%. Two studies examined use of AIs alone while the remainder included patients treated with either AIs or tamoxifen. Five out of seven studies suggested a negative impact of obesity on AI efficacy. CONCLUSIONS: The results of our systematic review highlight a need for further research exploring the optimal endocrine therapies for obese women. There is insufficient evidence at present to recommend tailoring adjuvant endocrine therapy with use of specific AIs or for dosing modifications of AIs in this patient population.
BACKGROUND: The relationship between obesity and prognosis of early breast cancer is complex. Increased levels of aromatase present in adipose tissue of obese postmenopausal women may lead to suboptimal suppression of systemic estrogens. However, studies have been mixed with respect to the association between use of aromatase inhibitors (AIs) and clinical outcomes in obesewomen with early breast cancer. METHODS: We conducted a systematic literature review following PRISMA guidelines to examine the impact of obesity on the efficacy of AIs in early-stage hormone receptor-positive breast cancer. Primary outcome measures included disease-free survival, relapse-free survival, distant recurrence-free survival, breast cancer-free survival, and overall survival. RESULTS: Of 491 studies identified, eight studies met criteria for inclusion: three retrospective cohort studies, one prospective cohort study and four randomized controlled trials. Four studies limited eligibility to postmenopausal women. Percentage of obesepatients in studies ranged from 10 to 30%. Two studies examined use of AIs alone while the remainder included patients treated with either AIs or tamoxifen. Five out of seven studies suggested a negative impact of obesity on AI efficacy. CONCLUSIONS: The results of our systematic review highlight a need for further research exploring the optimal endocrine therapies for obesewomen. There is insufficient evidence at present to recommend tailoring adjuvant endocrine therapy with use of specific AIs or for dosing modifications of AIs in this patient population.
Entities:
Keywords:
Anastrozole; Aromatase inhibitor; Breast cancer; Exemestane; Letrozole; Obesity