Homologous Recombination Repair Status as a Biomarker of Response in Locally Recurrent/Metastatic Triple Negative Breast Cancer Patients Treated With Concurrent Cisplatin and Radiation Therapy

Radiation therapy to the target tumor will be delivered with external beam radiation therapy. In metastatic cases where the intent is palliative, the dose of radiation will be 3750 cGy delivered in 15 daily fractions, 4-5 days a week. In locoregionally recurrent cases where the intent is to enhance locoregional control, the dose of radiation will be 5000 cGy delivered in 25 fractions, 4-5 days a week plus an optional 10-14 Gy boost to areas of gross tumor.

Cisplatin treatment should be initiated following study registration. The dose of cisplatin is established as 25 mg/m\^2 ivpb once a week (+ 3 days) for 1-2 weeks prior to radiation. The length of one cycle of Cisplatin is 21 days.

Biopsy of the tumor to be irradiated will be performed. Fresh tissue specimens will be sent to the laboratory for performance of the MSK-HRR Assay.