Lapierre 2007.

Methods	Design: Parallel group RCT Country: France Multicentre study: No Setting: Hospital Follow‐up: 6 months Unit of allocation: Patients Unit of analysis: Patients
Participants	Inclusion criteria: "Patients included in the trial were more than 18 years of age and of both sexes and were to undergo surgery for cancer...with a transfusion‐during‐surgery (TdS) risk greater than 30 percent". Exclusion criteria: "Patients were not eligible for inclusion if they presented contraindications to the use of UN‐RBCs or presented any RBC antibodies and/or anti‐HLA and/or antigranulocyte alloimmunization" (page 1692). Patients enrolled: 161 Patients randomised: 37 Unmodified RBCs (UN‐RBC): 19 Leukoreduced RBCs (LR‐RBC): 18 Patients transfused: 36 Patients considered for the analysis: 35 Main characteristics of patients: Age = Median (range): Unmodified RBCs group = 56 (40 to 73) years; Leukoreduced RBCs group= 54 (37 to 65) years Percentage of men: Unmodified RBCs group = 33%; Leukoreduced RBCs group = 47% Tumour location: Pelvis: Unmodified RBCs group = 11; Leukoreduced RBCs group = 8. Head and neck: Unmodified RBCs group = 6; Leukoreduced RBCs group = 7. Miscellaneous: Unmodified RBCs group = 1; Leukoreduced RBCs group = 2 Blood loss = Median (range): Unmodified RBCs group = 1500 (300 to 3650) mL; Leukoreduced RBCs group = 1325 (300 to 6800) mL
Interventions	Unmodified RBCs. Leukoreduced RBCs (post‐storage leukoreduction). Cointervention: Two patients (11%) in the unmodified RBCs group and three patients (18%) received fresh‐frozen plasma. None of the patients received platelet concentrate.
Outcomes	"The main endpoint of the study was to compare immune status in both treatment groups" (page 1692). This was measured through surrogate variables (i.e. microchimerism, peripheral blood cell counts and cytokine production capacity). However, other outcomes were described: "In addition to immune status, other factors compared between the two groups were survival and incidence of nosocomial infection" (page 1694).
Notes	Trial registration: ClinicalTrials database NCT00180869 Funding: "grants from the French Association for Cancer Research (L'Association pour la Recherche sur le Cancer [9653]) and the French Association for Blood Transfusion Research (L'Association pour la Recherche enTransfusion [081997])" (page 1691) Role of sponsor: Not stated A priori sample size estimation: Yes Conducted: between 15 September 1997 and 28 February 1998 Declared conflicts of interest: Not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "The randomization was performed centrally by computer in the Gustave Roussy Cancer Institute Biostatistics Unit after the investigator had sent a fax indicating the minimization factors of the patient" (page 1693).
Allocation concealment (selection bias)	Unclear risk	Comment: Insufficient information to permit judgement of ‘low risk’ or ‘high risk’.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "Patients and surgeons were not blinded of the treatment allocation" (page 1693).
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "Patients and surgeons were not blinded of the treatment allocation" (page 1693).
Incomplete outcome data (attrition bias) All outcomes	Low risk	36 patients were transfused: 18 received unmodified RBCs (UN‐RBC) and 18 received Leukoreduced RBCs (LR‐RBC). Loss after transfusion: 2.77% (1/36). Loss after transfusion LR group: 1 died during surgery. Loss after transfusion Control group: None. Loss after transfusion. Imbalance between comparison groups: 5%.
Selective reporting (reporting bias)	Unclear risk	Survival after perioperative transfusion is reported in Figure 2. However, number of death is not clearly reported.
Other bias	Unclear risk	Comment: Sample size estimate was calculated based on Th2 polarization. It is unclear what dropout rate was considered in the sample size estimation of 75 participants.