Definitive Interstitial Brachytherapy for Isolated Cutaneous Metastasis in Breast Cancer.

Cutaneous metastasis as the sole site of recurrence in breast cancer is rare and poses a unique therapeutic challenge due to limited consensus on optimal management strategies. We present the case of a 40-year-old female with isolated cutaneous metastasis over the left side of the neck from previously treated breast cancer, presenting 1.5 years after completion of primary therapy. Following evaluation, the patient was treated with interstitial high-dose-rate brachytherapy, followed by maintenance systemic therapy with anastrozole and palbociclib. At six months of follow-up, she achieved a complete clinical response with minimal toxicity. This case highlights the potential role of interstitial brachytherapy as an effective, organ-preserving treatment modality in selected patients with isolated cutaneous metastasis.