Paci 2017.

Study characteristics
Methods	Trial design: phase 3 randomised control trial  Duration of follow‐up: median follow‐up 11 years Number of trial locations: 3
Participants	Baseline characteristics Number of participants: LDCT arm (1613); control arm (1593) Age LDCT arm: 55‐59 years old (734), 60‐65 years old (580), > 65 years old (299) Control arm: 55‐59 years old (670), 60‐65 years old (626), > 65 years old (297) Sex: LDCT arm (1035 males, 578 females); control arm (1039 males, 554 females) Smoking status: LDCT arm (1060 current, 553 former); control arm (1019 current, 575 former) Performance status: not published Ethnicity/race: not published  Environmental exposures: not published Inclusion criteria 55 to 69 years old at time of enrolment Resident in the trial catchment area Current smoker or former smoker (quit < 10 years) with at least a 20 pack‐year history  Exclusion criteria Former smokers who quit > 10 years ago or never‐smokers  Previous cancer other than non‐melanoma skin cancer General conditions precluding thoracic surgery Preintervention investigations Nil
Interventions	Intervention characteristics Frequency of scanning: annual  LDCT setting: 120 kVP to 140 kVP, 20 mA to 43 mA Duration of screening: 4 years  Interpretation of scans Volumetric or size criteria: size  Use of volumetry software: no   Criteria for significance: at least one non‐calcified nodule ≥ 5 mm or a non‐solid nodule ≥ 10 mm or the presence of a part‐solid nodule Prespecified protocol for nodule follow‐up: yes Comparison Description: no screening
Outcomes	Primary outcome Lung cancer‐specific mortality  Secondary outcomes  All‐cause mortality  Lung cancer incidence excess/overdiagnosis
Identification	Sponsorship source: Local government of Tuscany, Italian Ministry of Education, University and Research Country: Italy Setting: screening centres Trial start date: September 2003 Completion of follow‐up: December 2014 Trial registration number: NCT02777996 Corresponding author's name: Eugenio Paci Institution: Prevention and Research Institute, Florence, Italy  Email: paci.eugenio@gmail.com
Notes	Conflicts of interest: nil reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Central randomisation using software
Allocation concealment (selection bias)	Low risk	Central randomisation using software
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants were aware of the allocation
Blinding of outcome assessment (detection bias) All outcomes	Low risk	All participants followed up via cancer registry of the Tuscany region for incidence and mortality. Each CT was read independently by two radiologists on a work station with a consensus reached in case of disagreement. Independent committee reviewed and revised cause of death in a blinded fashion for those cases which met their prespecified criteria following assessment of death certificate and available hospital notes. 31 deaths out of 335 deaths (9%) underwent review with the committee by December 2014. Following cessation of active follow‐up in December 2014, deaths were determined via linkages to registries. The same prespecified algorithm was used for determining cause of death, however whether any cases were reviewed by the committee was unclear.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Moderately significant dropouts and low adherence (81% to screening adherence), however intention‐to‐treat analysis was applied.
Selective reporting (reporting bias)	Low risk	All outcomes published
Other bias	Low risk	No protocol deviations