Measurement of upper extremity volume in women after axillary dissection for breast cancer

Abstract

Objective: To determine if 2 methods of calculating upper extremity volume (using arm circumferences) can substitute for water displacement volumetry.

Design: Interrater and test-retest reliability and limits of agreement for volume measures.

Setting: University.

Participants: Twenty-five women at risk for lymphedema who had undergone axillary lymph node dissection surgery for breast cancer.

Interventions: Circumference and volume measurements of both upper extremities were taken by 2 physical therapists at an initial visit and by 1 of the therapists 1 week later.

Main outcome measures: Intraclass correlation coefficients (ICCs) were calculated to analyze measurement reliability. Pearson's product-moment correlation coefficient (r) was used to evaluate the relationship between volumetry and calculated truncated cone volumes. Limits of agreement were calculated to determine the level of agreement between the 2 measurement methods.

Results: Interrater and test-retest reliability ICCs for circumferential and volumetric data were .99 and .99, respectively. Pearson's r values were .93 and .97 for the single truncated cone and the summed truncated cone volume calculations, respectively. Limits of agreement (mean +/- 2 standard deviations) were -52 +/- 334mL and -40 +/- 234mL, respectively, between volumetry and the single truncated cone and summed truncated cone calculations.

Conclusions: Calculated and volumetric measurements in this population are both reliable and closely related, but do not agree with each another, and thus should not be used interchangeably.