This study will examine the outcomes of lumpectomy, surgery to remove a tumor, without sentinel node biopsy (SNB) for women at least 65 years of age with clinically node-negative breast cancer. Clinically node-negative means that during a physical exam your doctor cannot feel or see that any lymph nodes near the breast area are swollen and there is also no imaging evidence, such as from a mammogram, of nodal involvement.

The primary objective of the study is to determine whether omission of sentinel node biopsy in patients who meet eligibility criteria results in an acceptable regional recurrence rate over a 6-year period. A regional recurrence is defined as any recurrence in the ipsilateral axillary nodes, supraclavicular nodes or internal mammary nodes.

Eligible patients will undergo standard of care lumpectomy without sentinel node biopsy followed by radiation and hormonal therapy or have already undergone the procedure prior to enrollment in the study. She may also receive chemotherapy as determined by her treating physician. A physical examination of the affected breast and regional lymph nodes will be conducted every six months for the first two years of follow up and then yearly for the last 3 years of follow up. Imaging of the affected breast will occur every 12 months after surgery per standard of care.

Inclusion Criteria:

• Female age 65 and older

• Staging:

  1. Patients enrolled prior to surgery: Diagnosis of clinical T1-2N0, ER+, HER2-negative, invasive breast cancer as determined by treating physician. DCIS or LCIS may be present with invasive cancer.
  2. Patients enrolled after surgery: pT1-2NX, or pT1-2N0, ER+, HER2-negative, invasive breast cancer. DCIS or LCIS may be present with invasive cancer.

• Plan to undergo lumpectomy within 3 months of study registration, or underwent lumpectomy within 60 days of study registration (without sentinel node biopsy)

• Patients in whom lymph nodes are palpable and not suspicious who are found to be nodal tumor-free by nodal core needle biopsy are permitted, but those with biopsy-proven nodal metastases are excluded

Exclusion Criteria:

• Patients with diagnosis of ductal or lobular carcinoma in situ
• Patients with diagnosis of inflammatory breast cancer
• Patients who have undergone neoadjuvant chemotherapy for current primary breast cancer (past treatments for other cancers are acceptable)
• Patients planning to have mastectomy or had a mastectomy of the ipsilateral breast
• Prior history of ipsilateral (invasive or DCIS) breast cancer
• Diagnosis of clinical T3 or T4 breast cancer