Radiation Therapy for Breast Cancer With Oligometastatic Cervical Lymph Nodes: A Case Report

Stage IV breast cancer is difficult to cure and is mainly treated with systemic therapy. However, when distant metastasis is oligometastatic, proactive treatment including local therapies for the primary lesion and distant metastases has been reported to improve prognosis. We encountered a patient who had left breast cancer with ipsilateral cervical lymph node metastases. The metastases were oligometastatic, and we treated them curatively. The patient was a female in her 50s who had been aware of a lump in the lower inner quadrant of the left breast for a few years. A biopsy was performed and left breast cancer was diagnosed pathologically. Radiological examination showed metastasis to ipsilateral axillary and cervical lymph nodes. The cervical lymph node metastases were oligometastatic, suggesting possible improvement in prognosis by multimodality treatment including local therapy. The multimodality treatment in this case comprised mastectomy with levels I and II axillary lymph node dissection, systemic therapy (including chemotherapy, endocrine therapy, and molecular targeted therapy), and postmastectomy radiation therapy. The left chest wall and left supraclavicular lymph node region were irradiated. Furthermore, following the postmastectomy radiation therapy, the cervical lymph node metastases were treated with radical radiation therapy. The cure was achieved, with recurrence-free status maintained for two years and four months after the completion of radiation therapy. This case suggests that, for breast cancer with oligometastatic involvement of cervical lymph nodes, locally treating these distant metastatic lesions with radical radiation therapy as part of multimodality treatment is beneficial.