E'dburgh Sample/Clear.

Methods	Study design: RCT Country: Scotland Study period: 1980‐1983 Inclusion criteria: patients with clinically operable invasive breast cancer (T1, T2, operable T3; N0, N1; M0). Fit enough for surgery and radiotherapy Exclusion criteria: those not available for continuous follow‐up, with in situ cancer, Paget’s disease of the nipple, multiple ipsilateral or contralateral breast cancer Length of follow‐up (median and range): 11.0 (2‐13) years
Participants	No. in trial arms: sampling: N = 203; ALND: N = 203 Age: sampling: median (range) = 58.7 (25.7‐77.1) years; ALND: median (range) = 57 (29.6‐76) years Stage distribution: not reported (most had T1 or T2 tumour and N0 or N1 nodes, some with operable T3 tumours were also enrolled) Proportion node positive: sampling: N = 88/203; ALND: N = 80/203 Pathological type of breast cancer: not reported
Interventions	Radical mastectomy with axillary node clearance (ALND; via the Patey technique, fat and nodal tissue were dissected to the level of the first rib) vs mastectomy with axillary node sample (sampling; the breast was dissected from the underlying chest wall from medial to lateral and the axillary tail mobilised). Nodes were identified by inspection and palpation of the axillary tail and connected fat, and 4 were removed for histological examination.
Outcomes	Overall survival, distant recurrence, locoregional recurrence, reduced arm mobility, severe interference with daily activities, persistent arm swelling
Axillary node surgery	Minimum no. nodes to be removed according to protocol: 4 nodes for axillary sample Nodes removed sampling arm: mean 6, median 4 (range, 0‐19) Nodes removed clearance arm: mean 20, median 20 (range, 5‐46) Method of node pathological analysis: sampling: Samples of the axillary tail of breast and related fat were palpated, and additional nodes dissected out, then fixed. ALDN: Specimens were assessed radiologically for determination of node distribution. Specimens then were placed on a cork board, and the nodes dissected out; these were then labelled separately or in groups and were fixed. Sections of all nodes were examined by histology. Further treatment for node positive cases: yes (radiotherapy)
Radiotherapy	RT node sampling arm: Postoperative radiotherapy (6‐MeV) was given to 82/86 participants with positive nodes, and to 2 with no identified nodes. Dose ranged from 4000 cGy to 4250 cGy; number of fractions ranged from 10 to 20 in 4 weeks (the radiotherapy protocol was modified over the course of the trial). RT node clearance arm: none RT same in all trial arms? no
Hormone and chemotherapy	Sampling: endocrine therapy (tamoxifen or oophorectomy) 84/203, chemotherapy (CMF) 10/203, no endocrine or chemotherapy 109/203 ALND: endocrine therapy (tamoxifen or oophorectomy) 96/203, chemotherapy (CMF) 8/203, no endocrine or chemotherapy 99/203
Notes	Protocol violations: sampling: N = 16, ALND: N =7 Baseline differences? Groups appear to be comparable at baseline. Intention‐to‐treat analyses? Survival, disease control in the axilla, breast cancer recurrence: Paper states that data were analysed according to the intention‐to‐treat principle. Long‐term adverse events: Arm morbidity was reported for only 33.2% of included participants chosen alphabetically from those known to be free of local and systemic disease; therefore, we have not included them.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details were provided.
Allocation concealment (selection bias)	Low risk	Central randomisation was performed by telephone from Scottish Cancer Trials Office (except for first 8 weeks, when participants were randomised in theatre with sequentially numbered cards).
Blinding of outcome assessment (detection bias) Disease control in the axilla	Unclear risk	No details were reported.
Blinding of outcome assessment (detection bias) Breast cancer recurrence	Unclear risk	No details were reported.
Blinding of outcome assessment (detection bias) Short term adverse events	Unclear risk	Outcome was not reported.
Blinding of outcome assessment (detection bias) Long term adverse events	Unclear risk	No details were reported.
Incomplete outcome data (attrition bias) Survival	Low risk	Data appear to be available for all participants.
Incomplete outcome data (attrition bias) Axillary recurrence	Low risk	Data appear to be available for all participants.
Incomplete outcome data (attrition bias) Breast cancer recurrence	Low risk	Data appear to be available for all participants.
Incomplete outcome data (attrition bias) Short term adverse events	Unclear risk	Outcome was not reported.
Incomplete outcome data (attrition bias) Long term adverse events	High risk	Arm morbidity was reported for only 33.2% of included patients chosen alphabetically from those known to be free of local and systemic disease; therefore, we have not included these data.
Selective reporting (reporting bias)	Unclear risk	Data on short‐term and long‐term adverse event outcomes are missing.