Preoperative sentinel lymph node (SLN) mapping by lymphoscintigraphy is helpful to evaluate extra-axillary SLNs over a wider range than the blue dye method. However, the clinical value of extra-axillary SLNs remains uncertain. The goal of this study was to determine the prevalence and clinical significance of supra- or infraclavicular drainage on preoperative lymphoscintigraphy in women with breast cancer.

We retrospectively reviewed the files of 942 consecutive breast cancer women who underwent preoperative lymphoscintigraphy for SLN biopsy at our institution between April 2004 and March 2015.

Supra- or infraclavicular drainage was detected in 5/942 women (0.5%) on preoperative lymphoscintigraphy. An axillary hot spot was detected in all five women, and a positive axillary SLN was detected in four women. Breast tumor locations were the upper inner or outer quadrants in four women and the lower outer quadrant in one woman. The median follow-up period was 75 months (mean: 92; range: 26–111 months). Recurrence outside the axilla was found in three (60%) women. The woman with a negative SLN status did not undergo adjuvant chemotherapy, but developed extra-axillary lymph node recurrence 3 years after primary surgery. No patient died of metastatic breast cancer at the last follow-up.

The detection of the supra- or infraclavicular SLNs on lymphoscintigraphy may provide additional staging information to tailor individual treatment regimens with regard to the potential risk of recurrence or metastasis of breast cancer.