Effect of arm position on circumference measurement of upper arms in healthy and in women with breast cancer-related lymphedema

Background: Arm circumference measurement for women with breast cancer-related lymphedema (BCRL) using a tape measure is reliable, valid, and widespread in clinical practice. Arm position for measurement varies among therapists and lacks uniformity in the literature. Objective: To examine the effect of arm position on total arm and segment volume for both arms in healthy women and women with BCRL. Design: Case-control study. Methods: Fourteen women in the maintenance phase of treatment of unilateral BCRL and 16 healthy women matched for age and body mass index. Three sequential circumferential measurements were performed in 2 different resting arm positions (90° supported forward flexion, dependent alongside the body) in both arms during 1 session. Arm volume was calculated using the summed truncated cone formula. Results: A nonsignificant interaction effect of arm (small vs large), position (horizontal vs vertical), and group (women with BCRL vs healthy women) on limb volume was noted (F 1,28 = 3.30, P =.08). While among women with BCRL (study group), the mean percentage volume change in the large arm between positions was lower than in the small arm (1.37% ± 1.97%) vs 1.61% ± 1.99%, respectively), the opposite was noted among healthy women (control group) (3.36% ± 1.45% vs 2.46% ± 1.59%, respectively). Limitations: Participants with BCRL presented with nonpitting mild lymphedema, and 2 specific positions that were selected limit the external validity to this stage of lymphedema and to these positions. Conclusions: Measurements should be performed in the same position; if not, according to the findings of this study, testing for systematic bias between positions should be performed.