Correlation between the drainage time in dynamic indocyanine green lymphography (ICG) and axillary lymph nodes metastatic involvement in breast cancer patients - a prospective study.

Introduction: Axillary lymph node staging is crucial in breast cancer management, influencing treatment decisions and prognosis. Axillary lymph nodes dissection (ALND) carries several complications, prompting the search for less invasive methods, especially after neoadjuvant chemotherapy. Indocyanine green (ICG) lymphography was primarily used for lymphatic mapping and sentinel lymph node evaluation. This study investigated the correlation between dynamic ICG lymphography drainage time and the pathological stage of axillary metastatic involvement. Methods: 45 female breast cancer patients undergoing ALND were enrolled. Dynamic ICG lymphography was performed the day before surgery, with intradermal injections in both upper limbs. ICG drainage time to the axillary region was recorded. Pathological and clinical lymph nodes stages (pN, cN) were determined. Statistical analyses included ANOVA, t-tests, and ROC analysis were performed. Results: The mean ICG drainage time was 625.6 ± 199.0 seconds. A statistically significant correlation was found between ICG drainage time and pN stage (p<0.05). Patients with pN2 and pN3 disease exhibited significantly prolonged drainage times compared to pN0 and pN1 patients. No significant difference was observed between pN0 and pN1. When categorizing patients into low-burden (pN0+pN1) and high-burden (pN2+pN3) groups, drainage time was significantly delayed in the high-burden group (525.8 ± 103.3 s vs. 900.1 ± 134.3 s; p<0.001). ROC analysis yielded an AUC of 0.995, with an optimal cut-off of 695 seconds, demonstrating excellent accuracy (sensitivity 100%, specificity 97%) in differentiating between low and high nodal burden. No correlation was found with time of drainage and cN, age, BMI, or arm circumference. Conclusion: Dynamic ICG lymphography drainage time correlates with pathological axillary nodal metastatic burden in breast cancer patients, particularly differentiating between low and high nodal involvement. This non-invasive functional assessment holds promise as a valuable adjunct for precise axillary management, guiding surgical de-escalation strategies, and potentially identifying patients at higher risk for lymphedema.