Eryilmaz 2005.

Methods	Study design: prospective RCT. Duration of study: January 2000 to July 2003.
Participants	Sample size: 45. Inclusion criteria: lactating women with breast abscesses presenting at the surgical clinic. Women were treated for mastitis prior to development of the abscess. Exclusion criteria: not reported. Setting: Department of surgery Vakif Gureba training hospital, Instanbul. Country: Turkey.
Interventions	1. Incision and drainage (n = 23) The procedure was done via the surgical OPD using local anaesthesia . The abscess was incised and the infected fluid was evacuated. The wound was left open to drain and dressed daily until the wound healed. A sample of the infected fluid was sent for bacteriological examination. Antibiotics were prescribed post‐operatively. Women were encouraged to feed from the unaffected breast and the breast with the abscess was emptied using breast pump. 2. Needle aspiration. Ultrasound guidance was not used (n = 22) It is unclear as to whether any anaesthesia was used during this intervention. Aspirations were repeated on alternate days until the abscess had completely resolved or until 5 needle aspirations had been performed. A sample of the infected fluid was sent for bacteriological examination. Antibiotics were prescribed post‐operatively Breastfeeding as per I&D group.
Outcomes	Primary outcomes and secondary outcomes. Authors did not differentiate between primary and secondary outcomes. Results of pus culture. Healing rate. Healing time. Recurrence. Cosmetic outcome‐incision and drainage. Pus volume. Number of aspirations. Definition of healing for incision and drainage group: healing was defined as time from incision and drainage to wound closure. Definition of failure for needle aspiration group: if after 5 aspirations which were done every other day the abscess was not resolved,  this was considered a failure of treatment.
Notes	Funding: not reported. Ethics approval: not stated. Informed consent obtained from the participants. Author contacted: yes, no response received. Below are the questions sent to the authors via email. Can you please advise on what system of randomisation was used? Was any method of allocation concealment used? At any stage of the study were assessors blinded and if so can you advise as to who these were? Can you advise on the mean and standard deviation of the patients that failed ultrasound drainage and had to have incision and drainage of abscess? Table 1 –Healing rate for the needle aspiration group is 13 (41%) There seems to be an error with the percentage‐can you please advise, we estimate it to be 59% Is it also possible for us to have a copy of your protocol for information that is generally not given in papers? Can you advise if the patients in the needle aspiration group received any anaesthesia? Can you please clarify what mean duration of lactation (line3) refers to (26% and 36% respectively)? Is this meant to read duration of lactation after procedure?
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Women were randomised 1:1. Method of randomisation not reported.
Allocation concealment (selection bias)	Unclear risk	Not described.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Although there was no blinding, it is unclear whether the resolution of the abscess would be affected.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No blinding was done. Blinding of outcome assessors is not possible due to the nature of the interventions and therefore difficult to judge whether this has an impact.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	9 women were excluded from the analysis in the needle aspiration group (mean healing time). The authors have not described how long the abscesses took to heal even after I&D.
Selective reporting (reporting bias)	Low risk	All prespecified outcomes were reported on.
Other bias	Unclear risk	Funding: authors did not declare any competing interests. Ethics approval: not stated. Informed consent obtained from the participants. Author contacted: yes.