RESUMO
PURPOSE: Despite increasing emphasis on screening and early intervention for breast cancer-related lymphedema (BCRL), there is marked heterogeneity in diagnostic methodology, including for volumetric measures. This retrospective study compared two volumetric modalities, perometry and simulated circumferential tape measurement (anatomic- and interval-based), for BCRL detection. METHODS: Between 2005 and 2017, 287 female patients with unilateral breast cancer were prospectively screened for BCRL by perometry and the relative volume change (RVC) formula. Circumferential measurement was performed by sampling at five anatomic landmark-based points or 4-cm intervals from pairs of perometer arm diameter measurements. Volumetric conversion was by a frustum model. The Bland-Altman method was used to compare segmental volume differences. Confusion matrix analysis was performed for each circumferential measurement technique against perometry. RESULTS: Median follow-up was 34.7 months over 4 postoperative visits. There was no difference in total arm volume comparing any of the circumferential measurement techniques to perometry. Landmark-based methods significantly underestimated upper arm volume (mean difference - 207 mL [- 336, - 78 mL]) and overestimated forearm volume (mean difference + 170 mL [+ 105, + 237 mL]). Landmark-based methods had greater sensitivity and specificity compared to 4-cm interval methods for detection of both RVC ≥ 10 and 5-10%. Landmark-based methods were comparable to perometry for detection of RVC ≥ 10%, but sensitivity was only 63.2-66.7% for RVC 5-10%. CONCLUSIONS: This hypothesis-generating study suggested the superiority of anatomic landmark-based circumferential tape measurement compared to interval-based methods, while generating questions about the underestimation of upper arm volume and overestimation of forearm volume of circumferential tape measurement compared to perometry.