Smoot, B., Zerzan, S., Krasnoff, J., Wong, J., Cho, M., & Dodd, M. (2014). Upper extremity bioimpedance before and after treadmill testing in women post breast cancer treatment. Breast Cancer Research and Treatment, 148, 445–453.

DOI Link

Study Purpose

To determine the effects of vigorous cardiorespiratory exercises on upper extremity limb volume in women with breast cancer-related lymphedema (BCRL)

Intervention Characteristics/Basic Study Process

In this study, 133 women with a history of breast cancer were enrolled. Patients were grouped according whether or not they had BCRL (63 had a previous diagnosis of lymphedema). There was one single intervention of cardiorespiratory exercise on a treadmill. Participants gradually increased the intensity of the exercise until they requested to stop or the test monitor recommended it. Participants’ upper extremities were measured using bioimpedance spectroscopy before and after treadmill exercise. They were instructed to have no food or fluid within one hour of their appointment, no exercise for 24 hours prior, and to avoid alcohol in excess for 12 hours prior. Initially, participants rested for 10 minutes on the table in a supine position. Their arms were measured every 10 cm from the wrist before treadmill exercise. Patients with lymphedema used compression garments if this was their practice.

Sample Characteristics

  • N = 133  
  • AVERAGE AGE = 56.27 years (SD = 9.38 years)
  • FEMALES: 100%
  • KEY DISEASE CHARACTERISTICS: Breast cancer status at least six months postoperatively for unilateral breast cancer surgery; with or without BCRL; no active cancer; no cellulitis; excluded if they had absolute contraindications to exercise testing from the American College of Cardiology or American Heart Association or American College of Sports Medicine
  • OTHER KEY SAMPLE CHARACTERISTICS: English speaking; aged 18 years or older

Setting

  • SITE: University of California San Francisco Clinical and Translational Science Institute Research Center
  • SETTING TYPE: Research center at a university 
  • LOCATION: San Francisco, CA

Phase of Care and Clinical Applications

  • PHASE OF CARE: Late effects and survivorship

Study Design

Cross-sectional study of 133 women divided into two groups (63 with and 70 without BCRL)

Measurement Instruments/Methods

  • Bioimpedance spectroscopy
  • Resistance ratios (RRs): Unaffected or affected before and after treadmill exercise
  • Oxygen consumption measured by peak VO2 (highest level of oxygen consumption during testing)
  • Hemodynamics: Peak responses were made for heart rate, blood pressure, and rated perceived exertion
  • 12-lead electrocardiogram was monitored continuously
  • Circumferential arm volume: Measurements taken every 10 cm starting from the wrist (calculated using the formula for a truncated cone) before treadmill exercise only.  

Results

The amount of time since breast cancer diagnoses was significantly greater for women with lymphedema (7.5 years versus 4.92 years). Resistance ratios greater than 1 (unaffected side versus affected side) indicated that the affected limb had the greatest volume. Overall, women with lymphedema had greater RR in both limbs before and after treadmill exercise. However, RR was not statistically significant for this group after exercise. The women without BCRL experienced an increase in limb RR after exercise that was statistically significant. Bioimpedance resistance values increased in both groups. This reflects the physiological effects of exercise and fluid volume as a result of vasodilation in limbs. Overall, 78% of participants wore a compression sleeve during testing in the BCRL group. The lack of consistency in compression sleeve use makes it difficult to draw clear conclusions.  

Conclusions

This study only evaluated the immediate effects of one symptom-limited treadmill test on arm volume in women with and without BCRL. In addition, the inconsistency in the use of a compression sleeve, as well as the different durations and degrees of lymphedema, creates some confounding results. More research efforts with rigorous designs are needed to examine the effects of cardiorespiratory exercise on arm volume in women with and without BCRL.

Limitations

  • Small sample (< 100)
  • Baseline sample/group differences of import
  • Risk of bias (no blinding)
  • Risk of bias (no random assignment)

 

Nursing Implications

There is confusion regarding what type of exercise patients with BCRL should do. This research leans towards encouraging cardiovascular exercise, but additional research is needed. At this time, recommending a sleeve for all patients might be warranted.