arm volumes to evaluate lymphoedema treatment

Background: Lymphedema treatment outcome can be evaluated by calculating estimated limb volumes directly by water displacement (plethysmography; PG), or indirectly by circumference measurements and using the formula for a truncated cone. We assessed the correlation between PG and circumference volume measurements to assess whether the correlation is acceptable, and if circumference measurements can be used to accurately assess arm volume. Methods: Ten women with unilateral lymphedema following breast cancer treatment with a mean age of 66 (range, 50–83) years volunteered for arm volume estimates by PG and circumference measurements. The coefficient of variation (CV%) for all methods was calculated. Two Excel-based formulas of the truncated cone were developed; one for fixed 4cm intervals leading to 10 volume segments (CM-10-VS) and one for varying intervals leading to 4 volume segments (CM-4-VS). Results: The CV% was 0.609 for PG, 0.628 for CM-10-VS, and 0.632 for CM-4-VS. As expected, PG generated a significantly larger volume of both arms because it includes the hand. The difference between CM-10-VS and CM-4-VS measurements was not significant. All three measurement methods showed a high correlation coefficient ranging 0.813–0.915, and a regression coefficient ranging 0.863–1.089. The excess volume, which is used to determine treatment outcome, showed the respective values of 0.932 to 0.978 and 0.963 to 1.020, respectively Conclusion: Using circumference measurements, identical to those used when ordering madeto-measure compression garments, speed up volume measurements and can be used safely to evaluate lymphedema treatment outcome.