Intra-Individual Comparison of Lymphatic Drainage Patterns Using Subareolar and Peritumoral Isotope Injection for Breast Cancer

Abstract

Background Controversy exists in the literature regarding the optimal site for lymphatic mapping in breast cancer. This study was designed to characterize lymphatic drainage patterns within the same patient after subareolar (SA) and peritumoral (PT) radiopharmaceutical injections and examine the impact of reader interpretation on reported drainage. Methods In this prospective trial, 27 women with breast cancer underwent sequential preoperative SA and PT injections of 0.5 to 2.7 mCi of technetium-99 m filtered sulfur colloid 3 days or more apart. Patterns of radiopharmaceutical uptake were reviewed independently by two nuclear medicine physicians. Inter-reader agreement and injection success were assessed in conjunction with observed drainage patterns. Results There was near perfect inter-reader agreement observed on identification of axillary LN drainage after PT injection (P = 0.0004) and substantial agreement with SA injection (P = 0.0344). SA injection was more likely to drain to only axillary LNs, whereas PT injection appeared more likely to drain to both axillary and extra-axillary LNs, although no statistically significant differences were found. All patients with extra-axillary drainage after PT injection (n = 6 patients) had only axillary drainage after SA injection. Dual drainage was observed for six patients with PT injection and one patient with SA injection. Conclusions Our findings suggest that radiopharmaceutical injected in the SA location has a high propensity to drain to axillary LNs only. After controlling for patient factors and demonstrating inter-reader agreement, the inability to demonstrate statistically significant differences in drainage based on injection site suggests that lymphatic drainage patterns may be a function of patient and tumorspecific features.

Superparamagnetic iron oxide as a tracer for sentinel node biopsy in breast cancer: A comparative non-inferiority study

“…24e28 Extraaxillary detection only occurred when the radiotracer injection was peritumoral, suggesting that extraaxillary tracer migration is more likely to happen in this case, which is in agreement with previous findings. 28,29 In any case, besides the fact that the indication of extraaxillary nodes biopsy is controversial, 20,24 this may be unnecessary when the tracer injection was subareolar only and, anyway, a preoperative lymphoscintigraphy could rule out this possibility. The control intervention was performed according to the standard protocol of each center.…”