A Personalized, Dynamic Physical Activity Intervention Is Feasible and Improves Energetic Capacity, Energy Expenditure, and Quality of Life in Breast Cancer Survivors

Purpose

Despite survival and quality of life benefits associated with physical activity, many breast cancer survivors remain inactive. Effective, sustainable interventions must account for individual differences in capability, motivation, and environment. Here, we evaluate the feasibility, mechanics, and efficacy of delivering an individualized, dynamic intervention to increase energetic capacity and energy expenditure.

Methods

Stage 0–III breast cancer patients who had completed primary treatment were enrolled. Prior to the intervention, detailed movement data was collected with a wearable GPS and accelerometer for 3 weeks to establish baseline activity. Movement data was collected continuously throughout the 12-week intervention, during which patients received electronically delivered, tailored, dynamic activity “prescriptions”, adjusted based on demonstrated individual capability, daily movement in their environment, and progress.

Results

Of 66 enrolled, 57 participants began and completed the intervention. The intervention resulted in significant improvements in average steps (+558 steps/day, p = 0.01), energetic capacity measured by power generation on a stationary bicycle (1.76 to 1.99 W/kg lean mass, p < 0.01), and quality of life (FACT-B TOI, 72.8 to 74.8, p = 0.02). The greatest improvement in functional energetic capacity was seen in the lowest performing tertile at baseline (0.76 to 1.12 W/kg, p < 0.01).

Discussion

Wearable technology delivery of personalized activity prescriptions based on individual capability and movement behaviors demonstrates feasibility and early effectiveness. The high variability seen in baseline activity and function, as well as in response to the intervention, supports the need for future work in precision approaches to physical activity (NCT03158519).

Impact of primary breast cancer therapy on energetic capacity and body composition

Purpose

This observational study was designed to measure baseline energy parameters and body composition in early-stage breast cancer patients, and to follow changes during and after various modalities of treatment. This will provide information to aid in the development of individualized physical activity intervention strategies.

Methods

Patients with newly diagnosed stage 0–III breast cancer were enrolled into three cohorts: A (local therapy alone), B (endocrine therapy), or C (chemotherapy with or without endocrine therapy). At baseline, 6 months, and 12 months, subjects underwent a stationary bicycle protocol to assess power generation and DEXA to assess body composition.

Results

Eighty-three patients enrolled. Patients had low and variable levels of power generation at baseline (mean power per kilogram lean mass 1.55 W/kg, SD 0.88). Power normalized to lean body mass (W/kg) decreased significantly, and similarly, by 6 months in cohorts B (1.42–1.04 W/kg, p = 0.008) and C (1.53–1.18 W/kg, p < 0.001). In all cohorts, there was no recovery of power generation by 12 months. Cohort C lost lean body mass (− 1.5 kg, p = 0.007), while cohort B maintained lean body mass (− 0.2 kg, p = 0.68), despite a similar trajectory in loss of power. Seven patients developed sarcopenia during the study period, including four patients who did not receive any chemotherapy (cohort B).

Conclusions

The stationary bike protocol was feasible, easy, and acceptable to patients as a way to measure energetic capacity in a clinical setting. Early-stage breast cancer patients had low and variable levels of power generation, which worsened following primary therapy and did not show evidence of ‘spontaneous recovery’ by 12 months. Effective physical activity interventions will need to be personalized, accounting for both baseline ability and the effect of treatment.

Electronic supplementary material

The online version of this article (10.1007/s10549-018-4924-6) contains supplementary material, which is available to authorized users.

Abstract P1-09-01: Beyond fatigue – The impact of breast cancer treatment on body composition and energy expenditure

Background: Patients (pts) frequently report ‘fatigue’ as a consequence of breast cancer therapy but the true impact of cancer treatments on body composition and energy expenditure has not been measured.

Patients and Methods: Pts with stage 0-III were evaluated prior to any therapeutic intervention to assess baseline health status, at 6 months to assess acute impact of therapy, and at 12 months to assess chronic effects and ‘spontaneous’ recovery. Measurements included body composition, maximum watts produced and power envelope (watts/kg) based on laboratory testing, energy expenditure over 7 days in real world conditions, insulin resistance (HOMA), fatigue (BFI), quality of life scales (FACT-B), and serum for insulin-like growth factor-1 (IGF-1), adiponectin, leptin, markers of bone formation (P1NP, BSAP, osteocalcin), bone resorption (sCTX), and bone mineral metabolism (PTH, 25-OH Vit D).

Results: 45 patients have been enrolled; 25 have completed the 6 month assessment to date. Median age was 52 (30-68). Patients were analyzed separately based on therapies received.

 Chemotherapy +/- HRTHormone TherapyLocal Therapy Only Baseline (n=23)6 months (n=12)Baseline (n=14)6 months (n=11)Baseline (n=8)6 months (n=2)BMI (kg/m2)27.826.328.729.332.028.2Lean mass (kg)39.536.342.041.143.036.1Body fat (%)43.947.346.550.649.445.6HOMA-IR*1.751.771.211.812.101.18Peak power (Watts)68.244.170539788.5Watts/kg lean muscle1.71,21.71.32.32.4Time to zero power (min.sec)^12.36.399.56.911.210.6*HOMA-IR was not assessed in patients known to have diabetes. ^Time to zero power quantifies the time over which patients can sustain generating motive power as a measure of endurance.

Week long bi-axial pedometry studies at baseline and six months revealed a decrease in pt activity between 17 and 23 percent, confirming the decrease in motive power seen in the power envelope and body composition tests. Enrollment continues to a planned total of 75 pts. Additional follow-up with 12 month assessment, as well as QOL and serum data will be presented.

Conclusions: Pts in this study were more deconditioned than expected based on population normative data. Systemic therapy had a profound impact on body composition with a substantial decrease in lean muscle mass with a corresponding increase in % body fat and decrease in the ability to generate and sustain motive power. Our data suggest that most patients would not be able to participate in or comply with commonly proposed exercise interventions and physical activity recommendations. Future interventions need to be restructured, following the model of individualized rehabilitation with careful assessment of the pts baseline status to improve the health of breast cancer survivors.

Citation Format: Kathy D Miller, Jessica L Sollars, Sandra K Althouse, Linda K Han, Stephen J Ventura, Jeffrey S Sledge. Beyond fatigue – The impact of breast cancer treatment on body composition and energy expenditure [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 P1-09-01.

GPS suggests low physical activity in urban Hispanic school children: a proof of concept study

Background

Urban environments can increase risk for development of obesity, insulin resistance (IR), and type 2 diabetes mellitus (T2DM) by limiting physical activity. This study examined, in a cohort of urban Hispanic youth, the relationship between daily physical activity (PA) measured by GPS, insulin resistance and cardiovascular fitness.

Methods

Hispanic middle school children (n = 141) were assessed for body mass index (BMI), IR (homeostasis model [HOMA-IR]), cardiovascular fitness (progressive aerobic cardiovascular endurance run [PACER]). PA was measured (GPS-PA) and energy expenditure estimated (GPS-EE) utilizing a global positioning mapping device worn for up to 7 days.

Results

Students (mean age 12.7 ± 1.2 years, 52% female) spent 98% of waking time in sedentary activities, 1.7% in moderate intensity PA, and 0.3% in vigorous intensity. GPS analysis revealed extremely low amounts of physical movement during waking hours. The degree of low PA confounded correlation analysis with PACER or HOMA-IR.

Conclusions

Levels of moderate and vigorous intensity PA, measured by GPS, were extremely low in these urban Hispanic youth, possibly contributing to high rates of obesity and IR. Physical movement patterns suggest barriers to PA in play options near home, transportation to school, and in school recess time. GPS technology can objectively and accurately evaluate initiatives designed to reduce obesity and its morbidities by increasing PA.

Measuring aerobic cycling power as an assessment of childhood fitness

The emergence of obesity, insulin resistance (IR), and type-2 diabetes (T2DM) in children requires a rational, effective public health response. Physical activity remains an important component of prevention and treatment for obesity, T2DM, and IR. Studies in adults show cardiovascular fitness (CVF) to be more important than obesity in predicting IR. We recently demonstrated that a school-based fitness intervention in children who were overweight can improve cardiovascular fitness, body composition, and insulin sensitivity, but it remains unclear whether accurate assessment of fitness could be performed at the school or outside of an exercise laboratory. The purpose of the study was to determine if a new methodology using measurement of cycling power could estimate cardiovascular aerobic fitness (as defined by maximum oxygen consumption; VO(2)max) in middle school children who were overweight. Thirty-five middle school children who were overweight (mean age 12 +/- 0.4 years) underwent testing on a power sensor- equipped Cycle Ops Indoor Cycle (IC), as well as body composition by dual x-ray absorptiometry (DXA), and VO(2)max by treadmill determination. Insulin sensitivity was also estimated by fasting glucose and insulin. Maximal heart rate (MHR) was determined during VO(2)max testing, and power produced at 80% of MHR was recorded. Spearman's rank correlation was performed to evaluate associations. Mean power determined on the IC at 80% of MHR was 129 +/- 77 watts, and average power at 80% MHR divided by total body weight (TBW) was 1.5 +/- 0.5. A significant correlation between watts/TBW was seen for VO(2)max (ml/kg/min) (p = 0.03), and significant negative correlation was seen between watts/TBW and fasting insulin (p < 0.05). In middle-school children who were overweight, there was a significant relationship between the power component of fitness and cardiovascular aerobic fitness (measured by VO(2)max). This more accessible and less intimidating field-based measure of power may prove useful in predicting changes in cardiovascular fitness. Thus, accurate assessment of childhood aerobic fitness may be achievable by measurement of power, possibly within the school environment at substantially less cost and effort than laboratory-based measurements.