Abstract P1-09-16: Exercise and the influence of endocrine therapy on cardiac and metabolic outcomes in breast cancer survivors
Authors: Knobf M Tish , Harris Lyndsey , Insogna Karl , Smith Barbara , Jeon Sangchoon 
Published: May 2015

Exercise and the Influence of Endocrine Therapy on Cardiac and Metabolic Outcomes in Breast Cancer Survivors

Background: Breast cancer survivors (BCS) are at higher risk for decreased cardiovascular fitness and illnesses due to excess weight and sedentary lifestyle. Exercise has been shown to improve fitness, body composition and helps to maintain weight but sparse data exists on the influence of endocrine therapy on these outcomes.

Methods: The Yale Fitness Intervention Trial (Yale FIT) was a 12 month RCT comparing aerobic-resistance exercise to home based physical activity. Female cancer survivors who were &lt; 3 years of completing primary and/or adjuvant chemotherapy and within the first 5 years of menopause therapy were eligible. The aerobic-resistance intervention was conducted at a community fitness center 3 times/week and included 30 minutes of aerobic and 20-30 minutes of resistance exercise, supervised by an interventionist for first 6 months. The home based group received a flyer outlining recommendations for 30 minutes moderate intensity physical activity most days of week. Data were collected at baseline, 6 and 12 months.

Results: The majority of the 154 women enrolled were white, married, employed and average age was 52 years. At baseline, mean BMI was 29 (+ 6.8), waist circumference 86.3 (+ 15.3) and subjects reported expending a median of 773 MET minutes per week. A graded exercise stress test was used to measure cardiovascular function. The fitness center group increased time on treadmill (p=0.05) and had improved heart rate recovery (p=0.01) when compared to the home based group. No significant differences were found across time for metabolic outcomes by fitness center or home based group. However, when analyzed by type of endocrine therapy (30% were on an Aromatase Inhibitor (AI), 31% on Tamoxifen (TAM) and 39% were on no endocrine (E) therapy), there was a significant difference in serum insulin and insulin resistance between the fitness center and home based group for women taking TAM at 6 months (p=0.03) and 12 months (p=0.01). Specifically the insulin levels in the fitness center group remained stable while the home based group demonstrated increased serum insulin and insulin resistance. There was a trend for women in the home based groups who gained weight (&gt; 5 lbs) to have higher insulin levels at 12 months (p=0.06). There were no significant changes at 6 or 12 months by group (fitness center or home based), by type of endocrine therapy or by weight change for total lipids, triglycerides, or HDL/LDL. To provide additional insight into the findings, analysis of cytokines and inflammatory markers is in progress.

Conclusions: This study confirms the cardiovascular fitness benefits of exercise but the relationship between exercise, endocrine therapy and weight on insulin levels is more complex. Exercise (aerobic-resistance and aerobic) combined with stable weight over 12 months resulted in relatively unchanged insulin levels. In contrast, only aerobic-resistance exercise (fitness center group) appeared to stabilize insulin levels in women who gained weight.

Funding: NIH/NCI R01CA122658.

Citation Format: M Tish Knobf, Lyndsey Harris, Karl Insogna, Barbara Smith, Sangchoon Jeon. Exercise and the influence of endocrine therapy on cardiac and metabolic outcomes in breast cancer survivors [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-09-16.