Altered lymphatic drainage after lymphadenectomy or radiotherapy of the axilla in patients with breast cancer

The incidental occurrence of lymph node metastasis in the contralateral axilla after previous treatment of breast cancer raises the question of whether these metastases derive from the original ipsilateral cancer or from a clinically occult contralateral cancer. A lymphoscintigraphic study was performed to investigate regional lymphatic drainage patterns of the breast and chest wall before and after axillary dissection or radiotherapy.