Prone Positioning CT Scan and Ultrasound Assessing Axillary Lymph Nodes in Patients With Breast Cancer Official Title: Evaluation of Axillary Lymph Nodes Using Prone Positioning Computed Tomography Scan and Ultrasound in Patients With Breast Cancer

A total of 500 patients who are newly diagnosed with operable breast cancer in Liaoning Oncology Hospital are approached and recruited. Inclusion criteria: 1. preoperative chest CT and axillary Doppler ultrasound examination in the prone position; 2. perform ALND; 3. regular follow-up post surgery, short-term and long-term. Exclusion criteria: history of other benign or malignant tumors causing axillary lymphadenopathy. Comparisons are made: A: between suspiciously positive and suspiciously negative axillary lymph nodes B: between LNSD positive among suspiciously positive axillary lymph nodes and negative axillary lymph nodes f C: between positive and negative AAUS D: between positive and negative AAUS among negative lymph nodes detected by CT scan E: between positive and negative AAUS among lymph nodes with negative LNSD Chi-square test and t test are used to assess statistical significance between groups. Methods: Lymph node short diameter (LNSD) is measured using CT scan imaging (LNSD \> 1cm is considered positive), axillary lymph node status is assessed according to axillary lymph node Doppler ultrasound. ALND will be performed in patients with positive axillary lymph nodes on CT scan; PALND will be performed for those with negative axillary lymph nodes on CT scan but positive on AAUS; SLNB will be performed for those with negative axillary lymph nodes on CT scan and on AAUS. The prognosis in each patient group is to be evaluated by short-term observational indicators (e.g. lymphedema and/or status of axillary lymphatic return), and long-term indicators (e.g. lymphedema and/or axillary lymph node recurrence). The accuracy of CT scan assessing positive lymph nodes and positive AAUS will be evaluated according to the postoperative histology results.