TY - JOUR
T1 - The effects of metformin and weight loss on biomarkers associated with breast cancer outcomes
AU - Patterson, Ruth E.
AU - Marinac, Catherine R.
AU - Sears, Dorothy D.
AU - Kerr, Jacqueline
AU - Hartman, Sheri J.
AU - Cadmus-Bertram, Lisa
AU - Villaseñor, Adriana
AU - Flatt, Shirley W.
AU - Godbole, Suneeta
AU - Li, Hongying
AU - Laughlin, Gail A.
AU - Oratowski-Coleman, Jesica
AU - Parker, Barbara A.
AU - Natarajan, Loki
N1 - Funding Information:
Dr. Hartman was supported under Award Number K07CA181323; Dr. Cadmus-Bertram was supported under Award Number K07CA178870; and Dr. Adriana Villaseñor was supported by a Diversity Research Supplement from the Continuing Umbrella of Research Experiences training program, as part of the National Cancer Institute Center to Reduce Cancer Health Disparities (3U54 CA155435-04S1).
Funding Information:
This work was supported by funding from the National Cancer Institute (U54 CA155435-01). Dr. Marinac was supported by the National Cancer Institute of the National Institutes of Health under Award Number F31CA183125;
Publisher Copyright:
© The Author(s) 2018. Published by Oxford University Press. All rights reserved.
PY - 2018/11/1
Y1 - 2018/11/1
N2 - Background: This study investigated the effects of metformin and weight loss on biomarkers associated with breast cancer prognosis. Methods: Overweight/obese postmenopausal breast cancer survivors (n ¼ 333) were randomly assigned to metformin vs placebo and to a weight loss intervention vs control (ie, usual care). The 2 2 factorial design allows a single randomized trial to investigate the effect of two factors and interactions between them. Outcomes were changes in fasting insulin, glucose, C-reactive protein (CRP), estradiol, testosterone, and sex-hormone binding globulin (SHBG). The trial was powered for a main effects analysis of metformin vs placebo and weight loss vs control. All tests of statistical significance were two-sided. Results: A total of 313 women (94.0%) completed the six-month trial. High prescription adherence (ie, 80% of pills taken) ranged from 65.9% of participants in the metformin group to 81.3% of those in the placebo group (P < .002). Mean percent weight loss was statistically significantly higher in the weight loss group (-5.5%, 95% confidence interval [CI] ¼ -6.3% to -4.8%) compared with the control group (-2.7%, 95% CI ¼ -3.5% to -1.9%). Statistically significant group differences (ie, percent change in metformin group minus placebo group) were -7.9% (95% CI ¼ -15.0% to -0.8%) for insulin, -10.0% (95% CI ¼ -18.5% to -1.5%) for estradiol, -9.5% (95% CI ¼ -15.2% to -3.8%) for testosterone, and 7.5% (95% CI ¼ 2.4% to 12.6%) for SHBG. Statistically significant group differences (ie, percent change in weight loss group minus placebo group) were -12.5% (95% CI ¼ -19.6% to -5.3%) for insulin and 5.3% (95% CI ¼ 0.2% to 10.4%) for SHBG. Conclusions: As adjuvant therapy, weight loss and metformin were found to be a safe combination strategy that modestly lowered estrogen levels and advantageously affected other biomarkers thought to be on the pathway for reducing breast cancer recurrence and mortality.
AB - Background: This study investigated the effects of metformin and weight loss on biomarkers associated with breast cancer prognosis. Methods: Overweight/obese postmenopausal breast cancer survivors (n ¼ 333) were randomly assigned to metformin vs placebo and to a weight loss intervention vs control (ie, usual care). The 2 2 factorial design allows a single randomized trial to investigate the effect of two factors and interactions between them. Outcomes were changes in fasting insulin, glucose, C-reactive protein (CRP), estradiol, testosterone, and sex-hormone binding globulin (SHBG). The trial was powered for a main effects analysis of metformin vs placebo and weight loss vs control. All tests of statistical significance were two-sided. Results: A total of 313 women (94.0%) completed the six-month trial. High prescription adherence (ie, 80% of pills taken) ranged from 65.9% of participants in the metformin group to 81.3% of those in the placebo group (P < .002). Mean percent weight loss was statistically significantly higher in the weight loss group (-5.5%, 95% confidence interval [CI] ¼ -6.3% to -4.8%) compared with the control group (-2.7%, 95% CI ¼ -3.5% to -1.9%). Statistically significant group differences (ie, percent change in metformin group minus placebo group) were -7.9% (95% CI ¼ -15.0% to -0.8%) for insulin, -10.0% (95% CI ¼ -18.5% to -1.5%) for estradiol, -9.5% (95% CI ¼ -15.2% to -3.8%) for testosterone, and 7.5% (95% CI ¼ 2.4% to 12.6%) for SHBG. Statistically significant group differences (ie, percent change in weight loss group minus placebo group) were -12.5% (95% CI ¼ -19.6% to -5.3%) for insulin and 5.3% (95% CI ¼ 0.2% to 10.4%) for SHBG. Conclusions: As adjuvant therapy, weight loss and metformin were found to be a safe combination strategy that modestly lowered estrogen levels and advantageously affected other biomarkers thought to be on the pathway for reducing breast cancer recurrence and mortality.
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U2 - 10.1093/jnci/djy040
DO - 10.1093/jnci/djy040
M3 - Article
C2 - 29788487
AN - SCOPUS:85053853257
SN - 0027-8874
VL - 110
JO - Journal of the National Cancer Institute
JF - Journal of the National Cancer Institute
IS - 11
M1 - djy040
ER -