Lymphatic drainage patterns in breast cancer patients who previously underwent mantle field radiation.

Background: Lymphatic drainage may change after radiation of a breast or its regional lymph node basins, and this may have implications for lymphatic mapping afterward. The aim of this study was to determine the lymphatic drainage patterns in breast cancer patients who had undergone mantle field radiation for Hodgkin's lymphoma in the past.

Methods: Between January 1999 and November 2008, 22 breast cancer patients underwent a sentinel node procedure after previous mantle field radiation. Lymphatic drainage patterns were analyzed based on lymphoscintigraphy and sentinel node biopsy. The results were compared with the drainage patterns in patients without previous treatment from an earlier study.

Results: Sentinel nodes were found in the axilla in 19 patients (86%) and 9 patients (41%) also had drainage toward extra-axillary regions. Sentinel nodes were more often found outside the axilla compared to the patients in our earlier study (33%, P = 0.04), and the nonidentification rate was also higher (14% vs. 3%, P = 0.01). Sentinel nodes were involved in 5 patients (23%). These were harvested from the internal mammary chain in two of them. No lymph node recurrences were observed during a median follow-up time of 49 months.

Conclusion: Lymphatic mapping is feasible and yields a lymph node in 86% of the breast cancer patients after previous mantle field radiotherapy for Hodgkin's lymphoma. Nonvisualization and extra-axillary nodes are more frequently encountered than in patients without a history of mantle field radiation. The finding of involved nodes suggests that sentinel node biopsy improves staging. Long-term follow-up will determine the sensitivity of the procedure in this specific situation.