Background: A few studies about lymphoscintigraphy in breast cancer patients have reported a correlation between decreased sentinel lymph node (LN) uptake and increased risk of axillary involvement with the hypothesis of blocked lymphatic passage of radiotracers by metastatic burden. This study is designed to investigate whether the visible internal mammary LN of lymphoscintigraphy (IM-LPS) is related to axillary LN metastasis, rather than identifying sentinel LN in the internal mammary area.
Methods: We retrospectively reviewed medical records of 401 breast cancer patients who underwent sentinel lymphoscintigraphy using Tc-99m phytate and subsequent axillary LN dissection. The IM-LPS was divided into positive or negative groups, and axillary lymphoscintigraphy (A-LPS) was visually graded into four groups according to the method suggested by Lee et al. (1) To evaluate the relation of positive IM-LPS and A-LPS pattern with axillary LN metastasis, multivariate logistic regression analysis was done with covariates of Memorial Sloan-Kettering Cancer Center model.
Results: Positive IM-LPS was found in 32 patients. On the univariate logistic regression analysis, positive IM-LPS (p=0.01) and A-LPS pattern (p<0.05) successfully predicted the axillary LN status. On the multivariate logistic regression model, positive IM-LPS (OR 2.6362; 95% CI 1.0382-6.6938; p=0.04) and group II A-LPS (OR 1.9773; 95% CI 1.1336-3.4491; p=0.01) remained statistically significant variables for the predictor of axillary LN metastasis.
Conclusion: This study suggests that IM-LPS and A-LPS pattern might be useful to show the burden of axillary LN metastasis in breast cancer patients, as an indicator of altered lymphatic pathway.