Dose-response effects of aerobic exercise on estrogen among women at high risk for breast cancer: a randomized controlled trial.

UNLABELLED: 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. PRIMARY OUTCOME: 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.

Geographic recruitment of breast cancer survivors into community-based exercise interventions.

PURPOSE: There is increased interest in developing and disseminating health behavior interventions for cancer survivors. Challenges in these efforts include participant burden in traveling to central intervention sites and sustainability. The purpose of this article is to report various methods used to recruit breast cancer survivors into an exercise intervention that attempts to address both of these challenges. METHODS: Letters were mailed within specific zip codes near community-based intervention sites in cooperation with state cancer registries. Additional recruitment methods included flyers at breast care clinics and support groups, mass media, and conferences. RESULTS: Of the 3200 women who responded, 82% (n = 2625) identified having heard about the study through state or hospital registry and 8% (n = 243) through print and broadcast media. Thirty-five percent (n = 103) of randomized women self-identified as having a minority racial background and 31.9% (n = 94) self-identified as African American. Comparisons of participant age and racial distribution to state cancer registries indicate similar age distribution but greater racial diversity among participants. CONCLUSION: These results support the use of population-based cancer registries to recruit survivors into community-based interventions and clinical trials.

Physical Activity and Lymphedema (the PAL trial): assessing the safety of progressive strength training in breast cancer survivors.

Lymphedema is a chronic and progressive long-term adverse effect of breast cancer treatment commonly defined by swelling of the affected arm. Current clinical guidelines indicate that women with and at risk for lymphedema should protect the affected arm from overuse. In clinical practice, this often translates into risk aversive guidance to avoid using the arm. This could lead to a disuse pattern that may increase the likelihood of injury from common activities of daily living. Further, such guidance poses an additional barrier to staying physically active, potentially translating to weight gain, which has been shown to be associated with worse clinical course for women with lymphedema. We hypothesize that a program of slowly progressive strength training with no upper limit on the amount of weight that may be lifted would gradually increase the physiologic capacity of the arm so that common activities represent a decreasing percentage of maximal capacity. Theoretically, this increased capacity should decrease the risk that daily activities put stress on the lymphatic system of the affected side. The Physical Activity and Lymphedema (PAL) Trial is a recently completed randomized controlled exercise intervention trial that recruited 295 breast cancer survivors (141 with lymphedema at study entry, 154 at risk for lymphedema at study entry). The purpose of this report is to provide detail regarding the study design, statistical design, and protocol of the PAL trial.