Arm Circumference and Volumetric Measurements in Breast Cancer Related Lymphedema

Volumetric measurement through water displacement and circumferential measurement is commonly employed for lymphedema diagnosis. This study aimed to investigate the association between diagnostic thresholds of circumferential and volumetric arm measurements in patients with breast cancer.

This was a cross-sectional study on patients with breast cancer related lymphedema presenting to a lymphedema clinic in Tehran between 2009 and 2019. Demographic characteristics, circumferential measurements (at seven time points along the upper limb), and volumetric measurements (using the water displacement method) were extracted from patient documents. Inter-limb circumference differences of >2 cm and ≥2 cm, >5 cm and ≥5 cm for the sum of all circumference measures, inter-limb volume differences of >10% and ≥10%, >200 and ≥200 ml were assessed. We examined the association between different indices by Cohen’s kappa coefficient and evaluated the accuracy of circumference measurements compared to volumetric measurements.

Totally 4647 cases were assessed for circumference and volumetric measurements. Substantial agreement was found between circumference index >2 and >5 cm (Kappa=0.720), and circumference index >2 and volumetric index >10% (Kappa =0.628). The >2cm index had a higher association with >200 ml (R2= 0.296). Considering the volume difference of >200 ml as a standard index, the ≥2 cm index had the highest sensitivity (90.74%) and accuracy (83.19%) compared to other indices.

Considering the index >200 ml as the standard volumetric threshold, the highest sensitivity and accuracy were related to the index ≥2 cm. About 30% of edema volume changes could be predicted by circumferential measurement. It seems that evaluating the effect of other variables influencing edema estimation should be assessed in future studies.