Sentinel lymph node biopsy is important for staging in patients with breast cancer and changes the way of surgery. One of the most commonly used methods to find the sentinel lymph node during surgery is to apply blue dye around the areola and then search for the sentinel lymph node. Breast massage is recommended following administration of the blue dye. However, the necessity of this massage is controversial. In this study, investigators will try to find out whether massage of the breast after blue dye injection has any positive effect on finding the sentinel lymph node.

This research is a prospective randomized study. Patients will be randomized by number-drawing method. Patients with BMI>30 and age>65 will be equally distributed to the experimental and active comparator arms. Under general anesthesia patients will be injected with 5 ml of isosulfan blue into the subareolar region. In one group, breast massage will be applied for 5 minutes. In the other group no massage will be applied. Surgical team will wait for a duration of 5 minutes for the self distribution of the blue dye.

Inclusion Criteria:

• the diagnosis of breast cancer by biopsy
• participants voluntarily participated in the clinical trial and signed informed consent

Exclusion Criteria:

• had previous sentinel lymph node biopsy or axillary surgery
• had neoadjuvant chemotherapy
• had clinical hints of axillary lymph node metastasis

individual participant data sharing will not contribute to other researchers

not necessary