Effective local control of apocrine carcinoma metastases via radiotherapy without immunotherapy

Apocrine carcinoma is a rare adnexal malignancy lacking standardized treatment strategies in the metastatic setting, with systemic therapies often yielding limited and short-lived responses. The role of radiotherapy in this context remains poorly defined. We report the case of a 49-year-old man with metastatic axillary apocrine carcinoma in whom immunotherapy was contraindicated due to active autoimmune disease requiring chronic immunosuppression. Following surgery and multiple lines of systemic chemotherapy, the patient developed lo­coregional and distant progression, including cutaneous, nodal, and skeletal metastases. Radiotherapy delivered to the axilla (30 Gy in 10 fractions) resulted in complete regression of clinically evident cutaneous disease, with durable local control despite ongoing systemic progression outside the irradiated field. Subsequent palliative radiotherapy to symptomatic bone metastases (20 Gy in 5 fractions) achieved prompt and sustained pain relief, accompanied by radiological evidence of recalcification. All treatments were well tolerated, with no observed acute or late toxicities. The repeated responses to radiotherapy observed in this case support the radiosensitivity of apocrine carcinoma and suggest its potential role as an effective local treatment modality across both cura­tive and palliative settings. In metastatic disease, where standardized systemic options are lacking, radiotherapy may represent a valuable component of multidisciplinary management, particularly when other therapies are ineffective or contraindicated.