Phase II Study of Single Agent Lenvatinib

Inclusion Criteria:

Patients must fulfill ALL the following inclusion criteria

* Female ≥18 years
* Histological or cytological diagnosis of breast carcinoma
* No prior treatment for current breast carcinoma
* Scheduled for upfront definitive breast cancer surgery (breast conserving surgery or mastectomy with or without sentinel lymph node biopsy or axillary lymph node clearance)
* Estrogen receptor positive (\>1%)
* Adequate bone marrow, renal and liver function
* Adequate organ function including the following:

  * Bone marrow:

    * Absolute neutrophil (segmented and bands) count (ANC) \>= 1.5 x 109/L
    * Platelets \>= 100 x 109/L
  * Hepatic:

    * Bilirubin \< = 1.5 x upper limit of normal (ULN),
    * ALT or AST \< = 2.5x ULN, (or \< = 5 X with liver metastases)
  * Renal:

    * Creatinine \< = 1.5x ULN
* Normal thyroid function
* Able to swallow pills
* Able to sign informed consent
* Able to comply with study-related procedures

Exclusion Criteria:

Patients will be excluded from the study for any of the following reasons:

* Scheduled for neoadjuvant systemic therapy
* Concurrent administration of any other tumor therapy, including cytotoxic chemotherapy, hormonal therapy, and immunotherapy.
* Treatment within the last 28 days with any investigational drug.
* Major surgery within 28 days of study drug administration.
* Pregnancy.
* Breast feeding.
* Serious concomitant disorders that would compromise the safety of the patient or compromise the patient's ability to complete the study, at the discretion of the investigator.
* Poorly controlled diabetes mellitus.
* Second primary malignancy that is clinically detectable at the time of consideration for study enrollment
* Symptomatic brain metastasis.
* History of significant neurological or mental disorder, including seizures or dementia.