Dose-response effects of aerobic exercise on estrogen among women at high risk for breast cancer: a randomized controlled trial.
Medical and surgical interventions for elevated breast cancer risk (e.g., BRCA1/2 mutation, family history) focus on reducing estrogen exposure. Women at elevated risk may be interested in less aggressive approaches to risk reduction. For example, exercise might reduce estrogen, yet has fewer serious side effects and less negative impact than surgery or hormonal medications. Randomized controlled trial. Increased risk defined by risk prediction models or BRCA mutation status. Eligibility: Age 18-50, eumenorrheic, non-smokers, and body mass index (BMI) between 21 and 50 kg/m(2). 139 were randomized. Treadmill exercise: 150 or 300 min/week, five menstrual cycles. Control group maintained exercise <75 min/week.


METHODS
Area under curve (AUC) for urinary estrogen. Secondary measures: urinary progesterone, quantitative digitized breast dynamic contrast-enhanced magnetic resonance imaging background parenchymal enhancement. Mean age 34 years, mean BMI 26.8 kg/m(2). A linear dose-response relationship was observed such that every 100 min of exercise is associated with 3.6 % lower follicular phase estrogen AUC (linear trend test, p = 0.03). No changes in luteal phase estrogen or progesterone levels. There was also a dose-response effect noted: for every 100 min of exercise, there was a 9.7 % decrease in background parenchymal enhancement as measured by imaging (linear trend test, p = 0.009). Linear dose-response effect observed to reduce follicular phase estrogen exposure measured via urine and hormone sensitive breast tissue as measured by imaging. Future research should explore maintenance of effects and extent to which findings are repeatable in lower risk women. Given the high benefit to risk ratio, clinicians can inform young women at increased risk that exercise may blunt estrogen exposure while considering whether to try other preventive therapies.
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA. schmitz@mail.med.upenn.edu.
Kathryn H
KH
Schmitz
Department of Kinesiology, Pennsylvania State University, State College, USA.
Nancy I
NI
Williams
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Despina
D
Kontos
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Susan
S
Domchek
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Knashawn H
KH
Morales
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Wei-Ting
WT
Hwang
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Lorita L
LL
Grant
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Laura
L
DiGiovanni
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Domenick
D
Salvatore
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Desire'
D
Fenderson
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Mitchell
M
Schnall
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Mary Lou
ML
Galantino
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Jill
J
Stopfer
Department of Nutrition, University of Minnesota, Minneapolis, USA.
Mindy S
MS
Kurzer
Department of Radiology, University of Pittsburgh, Pittsburgh, USA.
Shandong
S
Wu
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Jessica
J
Adelman
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Justin C
JC
Brown
Perelman School of Medicine, University of Pennsylvania, 8th Floor Blockley Hall, 423 Guardian Dr., Philadelphia, PA, 19104-6021, USA.
Jerene
J
Good
D000328:Adult; D015415:Biomarkers; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology / Q000652:urine*; D004967:Estrogens / Q000652:urine*; D015444:Exercise; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D017697:Premenopause; D011374:Progesterone / Q000652:urine; D018570:Risk Assessment; D012307:Risk Factors
D015415:Biomarkers; D004967:Estrogens; D011374:Progesterone
Breast MRI; Breast cancer; Clinical trial; Estrogens; Exercise