This is a Phase I dose escalation study of cisplatin and concurrent radiation in patients with ER negative, PR negative and HER2 negative breast cancer who have undergone breast-conserving surgery or mastectomy.

Primary objective: To assess the safety, tolerability, and maximum tolerated dose (MTD) of cisplatin when given concurrently with radiation therapy for participants with Stage II or III breast cancer who have undergone breast conserving surgery or mastectomy

This is a phase I dose escalation study of cisplatin and radiation to determine the toxicity of this combined treatment and establish an MTD.

Inclusion Criteria:

• Primary tumor is triple negative breast cancer
• Breast-conserving surgery or mastectomy with surgical excision of all gross disease with negative surgical margins
• Pathologic or clinical stage II or III disease
• At least 3 week interval from last chemotherapy administration/breast surgery to radiation (no more than 8 weeks)

Exclusion Criteria:

• Pregnant or breastfeeding
• Prior radiation to breast or ipsilateral regional nodes
• Ongoing therapy with other investigational agents
• Hormonal therapy
• Significant co-morbidity
• Pathologic complete response following preoperative chemotherapy
• Biopsy proven metastatic disease