Eligible patients was assigned in a 1:1 ratio to receive either low-dose capecitabine maintenance (intervention group) which is newly diagnostic to be planned to receive capecitabine after finishing the standard adjuvant treatment or observation (control group) within 4 weeks after completion of standard adjuvant chemotherapy.

Eligible patients will randomly open label assigned in a 1:1 ratio to receive either low-dose capecitabine maintenance (intervention group) which is newly diagnostic to be planned to receive capecitabine after finishing the standard adjuvant treatment or observation (control group) within 4 weeks after completion of standard adjuvant chemotherapy.

The capecitabine maintenance group will receive oral capecitabine at 650 mg/m2, twice daily continuously for 1 year.

Total follow up of the study is 2 years, one year for drug receving with monthy follow up for adverse effect and the other year for every 3 months follow up to asses DFS and OS.

Collection of capecitabine dose will receive and adverse events will assessed monthly during capecitabine maintenance in the capecitabine group. In both groups, physical examination, assessment of menopausal status, breast ultrasound, and abdominal ultrasound were performed every 3 months during 2 years of follow up; mammography and chest x-ray were performed yearly. Patients who has not experienced recurrence or death at the time of data analysis will censored as alive and event-free at the date of last follow-up.

Inclusion Criteria:

• Eligible trial participants will women who has pathologically confirmed invasive breast ductal carcinoma Hormone receptor negative (<1% positive cells by immunohistochemistry staining) and ERBB2 negative.

Participants had early-stage tumors that were stage T1b-3N0-3cM0, without positive supraclavicular or internal mammary lymph node.

They received standard treatments, including modified radical mastectomy or breast-conserving surgery, neo-/adjuvant chemotherapy, and radiotherapy according to institutional guidelines.

• patients were able to swallow tablets
• performance status 0 - 1

Exclusion Criteria:

• Key exclusion criteria will include Inflammatory or bilateral breast cancer. History of invasive breast cancer or other malignancies; receipt of other biologic agents or immunotherapy.

Lactation or pregnancy; or severe coexisting illness.

Eligible patients will randomly in a 1:1 ratio to receive either low-dose capecitabine maintenance (intervention group) which is newly diagnostic to be planned to receive capecitabine after finishing the standard adjuvant treatment or observation (control group) within 4 weeks after completion of standard adjuvant chemotherapy.

The capecitabine maintenance group will receive oral capecitabine at 650 mg/m2, twice daily continuously for 1 year.

Total follow up of the study is 2 years, one year for drug receving with monthy follow up for adverse effect and the other year for every 3 months follow up to asses DFS and OS.

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