Hyperspectral imaging as an objective diagnostic tool for secondary lymphedema in breast cancer patients

Secondary lymphedema is a common complication after breast cancer treatment. Traditional diagnostic techniques often lack objectivity, are prone to operator bias, and show limited reproducibility. There is a need for diagnostic methods that are reliable, noninvasive, and suitable for monitoring disease progression. This study (German Clinical Trials Register, DRKS-ID: DRKS00027366) aimed to evaluate hyperspectral imaging as a tool for detecting and classifying secondary lymphedema.

We conducted a prospective multicenter study including 58 women with unilateral secondary lymphedema. Lymphedema severity was categorized according to the International Society of Lymphology. Each participant underwent conventional assessments, including limb circumference measurements, two-point discrimination tests, joint mobility evaluation, and ultrasound imaging of skin and subcutaneous tissue, plus gave patient-reported outcomes. Hyperspectral images were collected using the TIVITA Tissue system, which captures light reflectance from 500 to 1000 nanometers. From these data, the lipid-to-water ratio and the TIVITA tissue water index were calculated to evaluate tissue changes related to lymphedema.

Here, we show that conventional methods correlate moderately with lymphedema stage, with ultrasound measurements of skin and subcutaneous thickness showing the strongest associations. Hyperspectral imaging shows strong correlations, with interlimb differences in lipid-to-water ratio and tissue water index outperforming conventional methods. These measurements highlight clear fluid accumulation in the affected limbs.

Hyperspectral imaging provides reproducible, objective, and noninvasive assessment of secondary lymphedema. These findings support its potential as a diagnostic and monitoring tool to improve staging and treatment evaluation.