IntroductionLung cancer screening (LCS) by low-dose CT has been shown to improve mortality, but individuals must consider the potential benefits and harms before making an informed decision about taking part. Shared decision-making is required for LCS in USA, though screening-eligible individuals’ specific views of these harms, and their preferences for accessing this information, are not well described.MethodsIn this qualitative study, we aimed to explore knowledge and perceptions around lung cancer and LCS with a focus on harms. We carried out seven focus groups with screening-eligible individuals, which were divided into current versus former smokers and lower versus higher educational backgrounds; and 16 interviews with health professionals including general practitioners, respiratory physicians, lung cancer nurse specialists and public health consultants. Interviews and focus groups were audio-recorded and transcribed. Data were coded inductively and analysed using the framework method.ResultsFatalistic views about lung cancer as an incurable disease dominated, particularly among current smokers, and participants were often unaware of curative treatment options. Despite this, beliefs that screening is sensible and worthwhile were expressed. Generally participants felt they had the ‘right’ to an informed decision, though some cautioned against information overload. The potential harms of LCS were poorly understood, particularly overdiagnosis and radiation exposure, but participants were unlikely to be deterred by them. Strong concerns about false-negative results were expressed, while false-positive results and indeterminate nodules were also reported as concerning.ConclusionsThese findings demonstrate the need for LCS information materials to highlight information on the benefits of early detection and options for curative treatment, while accurately presenting the possible harms. Information needs are likely to vary between individuals and we recommend simple information materials to be made available to all individuals considering participating in LCS, with signposting to more detailed information for those who require it.