Xu 2003.

Methods	Study design: RCT Country: China Study period: 1992‐2003 Inclusion criteria: "Females with invasive breast cancer of stage Ⅰor Ⅱ, who were hospitalised from Jun 1992 to October 1995, agreed and signed the informed consent form" Exclusion criteria: none reported Length of follow‐up (median and range): 99.5 months (12‐136 months)
Participants	No. in trial arm: Axillary dissection level 1 ± ovariectomy: N = 96; ALND ± ovariectomy: N = 96 Age median and range: Axillary dissection level 1 ± ovariectomy: 50.4 (31‐69) years; ALND ± ovariectomy: 48.3 (29‐69) years Stage distribution: Axillary dissection level 1 ± ovariectomy: clinical stage I/II: N = 17/79; TMN stage T1/T2/T3: N = 20/74/2; TMN stage N0/1/4/10: N = 62/23/8/3; ALND ± ovariectomy: clinical stage I/II: N = 12/84; TNM stage T1/T2/T3: N = 15/78/3; TNM stage N0/1/4/10: N = 56/26/11/3 Proportion node positive: unclear, but possibly as reported in the lines above Pathological type of breast cancer: not reported, but ER status was as follows: Axillary dissection level 1 ± ovariectomy: ER +/‐: N = 64/32; ALND ± ovariectomy: ER+/‐: N = 64/32
Interventions	Mastectomy and axillary dissection (level I axillary lymph nodes were cleared) ± ovariectomy (16 participants received ovariectomy) vs radical mastectomy ± ovariectomy (20 participants received ovariectomy; 35 underwent Halsted radical mastectomy; and 61 had a modified radical mastectomy operation (retaining pectoralis major muscle and medialis and lateralis branches of the thoracic nerve, cutting off the pectoralis minor muscle. The clearing scope of the axillary lymph node is the same as that for a Halsted radical mastectomy)).
Outcomes	10‐Year overall survival, 10‐year disease‐free survival, local recurrence, upper limb oedema, distant metastasis, involved upper limb disorder, cardiovascular events, cerebrovascular accident
Axillary node surgery	Minimum no. nodes to be removed according to protocol: see the next 3 lines Axillary dissection level 1 ±ovariectomy: Level Ⅰ lymph node clearance (only the lower axillary lymph nodes were cleared) ALND ±ovariectomy: Halsted radical mastectomy (all upper, middle and lower axillary lymph nodes were cleared) was performed for 35 participants, and 61 were treated with modified radical mastectomy (type Ⅱ). Method of node pathological analysis: "Confirmed by pathological examination" Further treatment for node‐positive cases: yes
Radiotherapy	"Postoperative radiotherapy was delivered to the internal mammary and clavicle area, to the metastasis in patients with axillary lymph node number ≥ 4, or to patients whose primary tumour were located inside to the nipple." Radiotherapy was given to 30 participants in the axillary dissection level 1 ± ovariectomy arm and to 42 in the ALND ± ovariectomy arm. RT same in all trial arms? yes
Hormone and chemotherapy	Postoperative adjuvant CMF chemotherapy was administered to participants with breast cancer stage Ⅰ‐Ⅱ, tumour size > 1 cm. The chemotherapy regimen was composed of CTX 500 mg/m2, 5‐FU 500 mg/m2, MTX 30 mg/m2. Axillary dissection level 1 ±ovariectomy: 34 participants completed 6 cycles of chemotherapy. ALND ±ovariectomy: 35 participants completed 6 cycles of chemotherapy Oral tamoxifen was given to participants after chemotherapy, to participants intolerant to chemotherapy and to ER‐positive participants (10 mg daily, 2 times a day).
Notes	The study was published in Chinese and was kindly translated and data extracted by Lixin Ma (School of Public Health, Hebei University, China). Risk of bias was discussed by 2 review authors. One review author entered this information into Review Manager. Baseline differences? Groups appear to be comparable at baseline. Intention‐to‐treat analyses? no. Analyses were per‐protocol.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"192 cases invasive breast cancer patients diagnosed as phase Ⅰ‐Ⅱ during the period from Jun 1992 to October 1995 signed informed consent, and participated in this study. They were randomly divided into two groups. 96 cases were in MAD ± ovariectomized group and 96 cases in RM± ovariectomized group." No further information was reported.
Allocation concealment (selection bias)	Unclear risk	"The selected patients were then acknowledged and allocated to two groups through sealed envelope." No further information was reported.
Blinding of outcome assessment (detection bias) Disease control in the axilla	Unclear risk	Information was collected from clinical records and clinical examination. No further information was reported.
Blinding of outcome assessment (detection bias) Breast cancer recurrence	Unclear risk	Information was collected from clinical records and clinical examination. No further information was reported.
Blinding of outcome assessment (detection bias) Short term adverse events	Unclear risk	Information was collected from clinical records and clinical examination. No further information was reported.
Blinding of outcome assessment (detection bias) Long term adverse events	Unclear risk	Information was collected from clinical records and clinical examination. No further information was reported.
Incomplete outcome data (attrition bias) Survival	Low risk	10‐Year follow‐up: loss to follow‐up: 3 participants in the level I clearance group; 8 in the ALND group. Participant flow chart was unavailable.
Incomplete outcome data (attrition bias) Axillary recurrence	Low risk	10‐Year follow‐up: Loss to follow‐up: 3 participants in the level I clearance group; 8 in the ALND group. Participant flow chart was unavailable.
Incomplete outcome data (attrition bias) Breast cancer recurrence	Low risk	10‐Year follow‐up: Loss to follow‐up: 3 participants in the level I clearance group; 8 in the ALND group. Participant flow chart was unavailable.
Incomplete outcome data (attrition bias) Short term adverse events	Low risk	10‐Year follow‐up: Loss to follow‐up: 3 participants in the level I clearance group; 8 in the ALND group. Participant flow chart was unavailable.
Incomplete outcome data (attrition bias) Long term adverse events	Low risk	10‐Year follow‐up: Loss to follow‐up: 3 participants in the level I clearance group; 8 in the ALND group. Participant flow chart was unavailable.
Selective reporting (reporting bias)	Unclear risk	Not enough information is available, and reporting of morbidity outcomes is limited.

5‐FU: 5‐fluorouracil.
 ALND: axillary lymph node dissection.
 BIS: bispectral index scale.
 CMF: cyclophosphamide, methotrexate, 5‐fluorouracil.
 CTX: cyclophosphamide.
 DFS: disease‐free survival.
 ER: oestrogen receptor.
 H&E: hematoxylin and eosin.
 IQR: interquartile ratio.
 ITT: intention‐to‐treat.
 NA: not applicable.
 MAC: minimal alveolar concentration.
 MTX: methotrexate.
 QOL: quality of life.
 RCT: randomised controlled trial.
 RT: radiotherapy.
 SD: standard deviation.
 SLN: sentinel lymph node.
 SLNB: sentinel lymph node biopsy.
 WHO PS: World Health Organization Perfomance Scale.