Minithoracotomy vs Conventional Sternotomy for Mitral Valve Repair: A Randomized Clinical Trial.

Importance: The safety and effectiveness of mitral valve repair via thoracoscopically-guided minithoracotomy (minithoracotomy) compared with median sternotomy (sternotomy) in patients with degenerative mitral valve regurgitation is uncertain. Objective: To compare the safety and effectiveness of minithoracotomy vs sternotomy mitral valve repair in a randomized trial. Design, Setting, and Participants: A pragmatic, multicenter, superiority, randomized clinical trial in 10 tertiary care institutions in the UK. Participants were adults with degenerative mitral regurgitation undergoing mitral valve repair surgery. Interventions: Participants were randomized 1:1 with concealed allocation to receive either minithoracotomy or sternotomy mitral valve repair performed by an expert surgeon. Main Outcomes and Measures: The primary outcome was physical functioning and associated return to usual activities measured by change from baseline in the 36-Item Short Form Health Survey (SF-36) version 2 physical functioning scale 12 weeks after the index surgery, assessed by an independent researcher masked to the intervention. Secondary outcomes included recurrent mitral regurgitation grade, physical activity, and quality of life. The prespecified safety outcomes included death, repeat mitral valve surgery, or heart failure hospitalization up to 1 year. Results: Between November 2016 and January 2021, 330 participants were randomized (mean age, 67 years, 100 female [30%]); 166 were allocated to minithoracotomy and 164 allocated to sternotomy, of whom 309 underwent surgery and 294 reported the primary outcome. At 12 weeks, the mean between-group difference in the change in the SF-36 physical function T score was 0.68 (95% CI, -1.89 to 3.26). Valve repair rates (≈ 96%) were similar in both groups. Echocardiography demonstrated mitral regurgitation severity as none or mild for 92% of participants at 1 year with no difference between groups. The composite safety outcome occurred in 5.4% (9 of 166) of patients undergoing minithoracotomy and 6.1% (10 of 163) undergoing sternotomy at 1 year. Conclusions and relevance: Minithoracotomy is not superior to sternotomy in recovery of physical function at 12 weeks. Minithoracotomy achieves high rates and quality of valve repair and has similar safety outcomes at 1 year to sternotomy. The results provide evidence to inform shared decision-making and treatment guidelines. Trial Registration: isrctn.org Identifier: ISRCTN13930454.

Conservative management versus tonsillectomy in adults with recurrent acute tonsillitis in the UK (NATTINA): a multicentre, open-label, randomised controlled trial.

BACKGROUND: Tonsillectomy is regularly performed in adults with acute tonsillitis, but with scarce evidence. A reduction in tonsillectomies has coincided with an increase in acute adult hospitalisation for tonsillitis complications. We aimed to assess the clinical effectiveness and cost-effectiveness of conservative management versus tonsillectomy in patients with recurrent acute tonsillitis. METHODS: This pragmatic multicentre, open-label, randomised controlled trial was conducted in 27 hospitals in the UK. Participants were adults aged 16 years or older who were newly referred to secondary care otolaryngology clinics with recurrent acute tonsillitis. Patients were randomly assigned (1:1) to receive tonsillectomy or conservative management using random permuted blocks of variable length. Stratification by recruiting centre and baseline symptom severity was assessed using the Tonsil Outcome Inventory-14 score (categories defined as mild 0-35, moderate 36-48, or severe 49-70). Participants in the tonsillectomy group received elective surgery to dissect the palatine tonsils within 8 weeks after random assignment and those in the conservative management group received standard non-surgical care during 24 months. The primary outcome was the number of sore throat days collected during 24 months after random assignment, reported once per week with a text message. The primary analysis was done in the intention-to-treat (ITT) population. This study is registered with the ISRCTN registry, 55284102. FINDINGS: Between May 11, 2015, and April 30, 2018, 4165 participants with recurrent acute tonsillitis were assessed for eligibility and 3712 were excluded. 453 eligible participants were randomly assigned (233 in the immediate tonsillectomy group vs 220 in the conservative management group). 429 (95%) patients were included in the primary ITT analysis (224 vs 205). The median age of participants was 23 years (IQR 19-30), with 355 (78%) females and 97 (21%) males. Most participants were White (407 [90%]). Participants in the immediate tonsillectomy group had fewer days of sore throat during 24 months than those in the conservative management group (median 23 days [IQR 11-46] vs 30 days [14-65]). After adjustment for site and baseline severity, the incident rate ratio of total sore throat days in the immediate tonsillectomy group (n=224) compared with the conservative management group (n=205) was 0·53 (95% CI 0·43 to 0·65; <0·0001). 191 adverse events in 90 (39%) of 231 participants were deemed related to tonsillectomy. The most common adverse event was bleeding (54 events in 44 [19%] participants). No deaths occurred during the study. INTERPRETATION: Compared with conservative management, immediate tonsillectomy is clinically effective and cost-effective in adults with recurrent acute tonsillitis. FUNDING: National Institute for Health Research.

Tonsillectomy compared with conservative management in patients over 16 years with recurrent sore throat: the NATTINA RCT and economic evaluation.

Background: The place of tonsillectomy in the management of sore throat in adults remains uncertain. Objectives: To establish the clinical effectiveness and cost-effectiveness of tonsillectomy, compared with conservative management, for tonsillitis in adults, and to evaluate the impact of alternative sore throat patient pathways. Design: This was a multicentre, randomised controlled trial comparing tonsillectomy with conservative management. The trial included a qualitative process evaluation and an economic evaluation. Setting: The study took place at 27 NHS secondary care hospitals in Great Britain. Participants: A total of 453 eligible participants with recurrent sore throats were recruited to the main trial. Interventions: Patients were randomised on a 1 : 1 basis between tonsil dissection and conservative management (i.e. deferred surgery) using a variable block-stratified design, stratified by (1) centre and (2) severity. Main outcome measures: The primary outcome measure was the total number of sore throat days over 24 months following randomisation. The secondary outcome measures were the number of sore throat episodes and five characteristics from Sore Throat Alert Return, describing severity of the sore throat, use of medications, time away from usual activities and the Short Form questionnaire-12 items. Additional secondary outcomes were the Tonsil Outcome Inventory-14 total and subscales and Short Form questionnaire-12 items 6 monthly. Evaluation of the impact of alternative sore throat patient pathways by observation and statistical modelling of outcomes against baseline severity, as assessed by Tonsil Outcome Inventory-14 score at recruitment. The incremental cost per sore throat day avoided, the incremental cost per quality-adjusted life-year gained based on responses to the Short Form questionnaire-12 items and the incremental net benefit based on costs and responses to a contingent valuation exercise. A qualitative process evaluation examined acceptability of trial processes and ramdomised arms. Results: There was a median of 27 (interquartile range 12-52) sore throats over the 24-month follow-up. A smaller number of sore throats was reported in the tonsillectomy arm [median 23 (interquartile range 11-46)] than in the conservative management arm [median 30 (interquartile range 14-65)]. On an intention-to-treat basis, there were fewer sore throats in the tonsillectomy arm (incident rate ratio 0.53, 95% confidence interval 0.43 to 0.65). Sensitivity analyses confirmed this, as did the secondary outcomes. There were 52 episodes of post-operative haemorrhage reported in 231 participants undergoing tonsillectomy (22.5%). There were 47 re-admissions following tonsillectomy (20.3%), 35 relating to haemorrhage. On average, tonsillectomy was more costly and more effective in terms of both sore throat days avoided and quality-adjusted life-years gained. Tonsillectomy had a 100% probability of being considered cost-effective if the threshold for an additional quality-adjusted life year was £20,000. Tonsillectomy had a 69% probability of having a higher net benefit than conservative management. Trial processes were deemed to be acceptable. Patients who received surgery were unanimous in reporting to be happy to have received it. Limitations: The decliners who provided data tended to have higher Tonsillectomy Outcome Inventory-14 scores than those willing to be randomised implying that patients with a higher burden of tonsillitis symptoms may have declined entry into the trial. Conclusions: The tonsillectomy arm had fewer sore throat days over 24 months than the conservative management arm, and had a high probability of being considered cost-effective over the ranges considered. Further work should focus on when tonsillectomy should be offered. National Trial of Tonsillectomy IN Adults has assessed the effectiveness of tonsillectomy when offered for the current UK threshold of disease burden. Further research is required to define the minimum disease burden at which tonsillectomy becomes clinically effective and cost-effective. Trial registration: This trial is registered as ISRCTN55284102. Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 12/146/06) and is published in full in Health Technology Assessment; Vol. 27, No. 31. See the NIHR Funding and Awards website for further award information.

Tonsillectomy is an operation to take out the pair of tonsil glands at the back of the throat. It is an option for adults who suffer from repeated, severe sore throats. Adults who have a tonsillectomy say that they get fewer sore throats afterwards, but it is not clear whether or not they would have got better over time without the operation. There is pressure on doctors to limit the number of tonsillectomies carried out. At the same time, emergency hospital admissions for adults with severe throat infections have been increasing. NAtional Trial of Tonsillectomy IN Adults aimed to find out whether tonsillectomy is an effective and worthwhile treatment for repeated severe sore throats or whether patients would be better off treated without an operation. A total of 453 patients from 27 hospitals in Great Britain took part in the study. Patients were assigned at random to receive either tonsillectomy or conservative management (treatment as needed from their general practitioner). We measured how many sore throats patients had in the next 2 years by sending them text messages every week. We asked about the impact of their sore throats on their quality of life and time off work, and looked at the costs of treatment. We also interviewed 47 patients, general practitioners and hospital staff about their experiences of tonsillectomy and NAtional Trial of Tonsillectomy IN Adults. The typical patient in the tonsillectomy arm had 23 days of sore throat compared with 30 days of sore throat in the conservative management arm. Tonsillectomy resulted in higher quality of life. We looked to see whether or not it was only those with the most severe sore throats who benefited from tonsillectomy, but we found that patients with more or less severe sore throats at the start all did better with tonsillectomy. Patients who had a tonsillectomy were happy to have undertaken this. Our findings suggest a clear benefit of tonsillectomy using modest additional NHS resources for adults with repeated severe sore throats.

Preoperative behavioural intervention to reduce drinking before elective orthopaedic surgery: the PRE-OP BIRDS feasibility RCT.

BACKGROUND: Heavy alcohol consumption is associated with an increased risk of postoperative complications and extended hospital stay. Alcohol consumption therefore represents a modifiable risk factor for surgical outcomes. Brief behavioural interventions have been shown to be effective in reducing alcohol consumption among increased risk and risky drinkers in other health-care settings and may offer a method of addressing preoperative alcohol consumption. OBJECTIVES: To investigate the feasibility of introducing a screening process to assess adult preoperative drinking levels and to deliver a brief behavioural intervention adapted for the target population group. To conduct a two-arm (brief behavioural intervention plus standard preoperative care vs. standard preoperative care alone), multicentre, pilot randomised controlled trial to assess the feasibility of proceeding to a definitive trial. To conduct focus groups and a national web-based survey to establish current treatment as usual for alcohol screening and intervention in preoperative assessment. DESIGN: A single-centre, qualitative, feasibility study was followed by a multicentre, two-arm (brief behavioural intervention vs. treatment as usual), individually randomised controlled pilot trial with an embedded qualitative process evaluation. Focus groups and a quantitative survey were employed to characterise treatment as usual in preoperative assessment. SETTING: The feasibility study took place at a secondary care hospital in the north-east of England. The pilot trial was conducted at three large secondary care centres in the north-east of England. PARTICIPANTS: Nine health-care professionals and 15 patients (mean age 70.5 years, 86.7% male) participated in the feasibility study. Eleven health-care professionals and 68 patients (mean age 66.2 years, 80.9% male) participated in the pilot randomised trial. An additional 19 health-care professionals were recruited to one of three focus groups, while 62 completed an electronic survey to characterise treatment as usual. INTERVENTIONS: The brief behavioural intervention comprised two sessions. The first session, delivered face to face in the preoperative assessment clinic, involved 5 minutes of structured brief advice followed by 15-20 minutes of behaviour change counselling, including goal-setting, problem-solving and identifying sources of social support. The second session, an optional booster, took place approximately 1 week before surgery and offered the opportunity to assess progress and boost self-efficacy. MAIN OUTCOME MEASURES: Feasibility was assessed using rates of eligibility, recruitment and retention. The progression criteria for a definitive trial were recruitment of ≥ 40% of eligible patients and retention of ≥ 70% at 6-month follow-up. Acceptability was assessed using themes identified in qualitative data. RESULTS: The initial recruitment of eligible patients was low but improved with the optimisation of recruitment processes. The recruitment of eligible participants to the pilot trial (34%) fell short of the progression criteria but was mitigated by very high retention (96%) at the 6-month follow-up. Multimethod analyses identified the methods as acceptable to the patients and professionals involved and offers recommendations of ways to further improve recruitment. CONCLUSIONS: The evidence supports the feasibility of a definitive trial to assess the effectiveness of brief behavioural intervention in reducing preoperative alcohol consumption and for secondary outcomes of surgical complications if recommendations for further improvements are adopted. TRIAL REGISTRATION: Current Controlled Trials ISRCTN36257982. FUNDING: This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 12. See the National Institute for Health Research Journals Library website for further project information.

Most patients undergoing knee and hip replacements are over 65 years old. Older patients have an increased risk of complications following surgery. Heavy alcohol consumption in the weeks before surgery increases the risk of complications after surgery, which can extend recovery times. Advice that helps patients reduce their alcohol consumption before surgery may have benefits for recovery. The PRE-OP BIRDS study had two parts: a feasibility study followed by a pilot randomised controlled trial with focus groups and an electronic survey used to characterise usual care in the preoperative assessment clinic. The feasibility study took place at one hospital. It aimed to develop materials that help health-care professionals provide brief advice to patients on how to reduce alcohol consumption before surgery. This brief advice was delivered to eligible patients and the acceptability to staff and patients was assessed in interviews. The pilot trial took place in three hospitals. Patients who agreed to take part were placed, by equal chance, into either a group that received usual care or a group that received usual care plus brief advice about reducing alcohol use. The aim was to count how many people agreed to take part and how many also agreed to complete a follow-up 6 months later. Interviews were carried out with patients and staff to explore their views on the intervention and the trial as a whole. All of this information was collected to help decide if a future larger trial was possible. This work found that the tools used were acceptable to both patients and staff. Although the number of people who agreed to take part was smaller than hoped, almost all of those who took part also completed the 6-month follow-up. Therefore, a future larger trial was found to be possible, but some changes could be made to encourage more people to take part.

Antiplatelet therapy in the primary prevention of cardiovascular disease in patients with chronic obstructive pulmonary disease: a randomised controlled proof-of-concept trial.

The APPLE COPD-ICON2 trial is a prospective 2×2 factorial, double-blinded proof-of-concept randomised controlled trial targeting patients with chronic obstructive pulmonary disease (COPD) without prior history of cardiovascular disease. The primary goal of this trial is to investigate if treatment with antiplatelet therapy will produce the predefined cut-off of platelet inhibition measured using the Multiplate test in COPD patients. Eligible patients were randomised to aspirin plus placebo, ticagrelor plus placebo, aspirin plus ticagrelor or placebo only for 6 months. The primary outcome comprises inhibition (binary response) of arachidonic acid- (ASPI test, cut-off <40) and adenosine diphosphate- (ADP test, cut-off <46) induced platelet aggregation at 6 months. 543 patients were screened and 120 patients were recruited with mean age of 67.5 years; 47.5% patients were male. The per-protocol ASPI test response rate to aspirin was 68.3% (95% CI 52.3-80.9%). The per-protocol ADP test response rate to ticagrelaor was 68.8% (95% CI 50.4-82.6%). Platelet response to antiplatelet therapy with aspirin and ticagrelor was not observed in nearly one-third of COPD patients without prior history of cardiovascular disease. These findings support the high pro-thrombotic milieu and the need for further research to determine the effect of antiplatelet/antithrombotic therapy on cardiovascular morbidity and mortality in COPD patients.

Preoperative Behavioural Intervention versus standard care to Reduce Drinking before elective orthopaedic Surgery (PRE-OP BIRDS): protocol for a multicentre pilot randomised controlled trial.

BACKGROUND: Evidence suggests that increased preoperative alcohol consumption increases the risk of postoperative complications; therefore, a reduction or cessation in alcohol intake before surgery may reduce perioperative risk. Preoperative assessment presents an opportunity to intervene to optimise patients for surgery. This multicentre, two-arm, parallel group, individually randomised controlled trial will investigate whether a definitive trial of a brief behavioural intervention aimed at reducing preoperative alcohol consumption is feasible and acceptable to healthcare professionals responsible for its delivery and the preoperative elective orthopaedic patient population. METHODS: Screening will be conducted by trained healthcare professionals at three hospitals in the North East of England. Eligible patients (those aged 18 or over, listed for elective hip or knee arthroplasty surgery and scoring 5 or more or reporting consumption of six or more units on a single occasion at least weekly on the alcohol screening tool) who enrol in the trial will be randomised on a one-to-one non-blinded basis to either treatment as usual or brief behavioural intervention delivered in the pre-assessment clinic. Patients will be followed up 1-2 days pre-surgery, 1-5 days post-surgery (as an in-patient), 6 weeks post-surgery, and 6 months post intervention. Feasibility will be assessed through rates of screening, eligibility, recruitment, and retention to 6-month follow-up. An embedded qualitative study will explore the acceptability of study methods to patients and staff. DISCUSSION: This pilot randomised controlled trial will establish the feasibility and acceptability of trial procedures reducing uncertainties ahead of a definitive randomised controlled trial to establish the effectiveness of brief behavioural intervention to reduce alcohol consumption in the preoperative period and the potential impact on perioperative complications. TRIAL REGISTRATION: Reference number ISRCTN36257982.

Antiplatelet therapy in the primary prevention of cardiovascular disease in patients with chronic obstructive pulmonary disease: protocol of a randomised controlled proof-of-concept trial (APPLE COPD-ICON 2).

INTRODUCTION: The antiplatelet therapy in the primary prevention of cardiovascular disease in patients with chronic obstructive pulmonary disease (APPLE COPD-ICON2) trial is a prospective 2×2 factorial, double-blinded proof-of-concept randomised controlled trial targeting patients with chronic obstructive pulmonary disease (COPD) at high risk of cardiovascular disease. The primary goal of this trial is to investigate if treatment with antiplatelet therapy will produce the required response in platelet function measured using the Multiplate test in patients with COPD. METHODS AND ANALYSIS: Patients with COPD are screened for eligibility using inclusion and exclusion criteria. Eligible patients are randomised and allocated into one of four groups to receive aspirin plus placebo, ticagrelor plus placebo, aspirin plus ticagrelor or placebo only. Markers of systemic inflammation, platelet reactivity, arterial stiffness, carotid intima-media thickness (CIMT), lung function and quality of life questionnaires are assessed. The primary outcome consists of inhibition (binary response) of aspirin and ADP-induced platelet function at 6 months. Secondary outcomes include changes in inflammatory markers, CIMT, non-invasive measures of vascular stiffness, quality of life using questionnaires (EuroQol-five dimensions-five levels of perceived problems (EQ5D-5L), St. George's COPD questionnaire) and to record occurrence of repeat hospitalisation, angina, myocardial infarction or death from baseline to 6 months. Safety outcomes will be rates of major and minor bleeding, forced expiratory volume in 1 s, forced vital capacity and Medical Research Council dyspnoea scale. ETHICS AND DISSEMINATION: The study was approved by the North East-Tyne and Wear South Research Ethics Committee (15/NE/0155). Findings of the study will be presented in scientific sessions and published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ISRCTN43245574; Pre-results.

Systematic review of participants' attitudes towards data sharing: a thematic synthesis.

Objectives Data sharing is well established in biological research, but evidence on sharing of clinical trial or public health research study data remains limited, in particular studies of research participants' perspectives of data sharing. This study systematically reviewed international evidence of research participants' attitudes towards the sharing of data for secondary research use. Methods Systematic search of seven databases, and author-, citation- and bibliography-follow up to identify studies examining research participants' attitudes towards data sharing. Studies were thematically analysed using NVivo v10 to identify recurring themes. Results Nine studies were eligible for inclusion. Thematic analysis identified four key themes: (1) benefits of data sharing, including benefit to participants or immediate community, benefits to the public and benefits to science or research; (2) fears and harms, such as fear of exploitation, stigmatization or repercussions, alongside concerns about confidentiality and misuse of data; (3) data sharing processes, in particular the role of consent in the process; and (4) the relationship between participants and research such as trust in different types of research or organization and the relationship with the original research team. Conclusions The available literature on attitudes towards sharing data from clinical trials or public health interventions remains scant. This study has identified four themes regarding research participants' attitudes and preferences, which should be considered by policy makers, and explored with further research.

Multicentre individual randomised controlled trial of screening and brief alcohol intervention to prevent risky drinking in young people aged 14-15 in a high school setting (SIPS JR-HIGH): study protocol.

INTRODUCTION: Drinking has adverse impacts on health, well-being, education and social outcomes for adolescents. Adolescents in England are among the heaviest drinkers in Europe. Recently, the proportion of adolescents who drink alcohol has fallen, although consumption among those who do drink has actually increased. This trial seeks to investigate how effective and efficient an alcohol brief intervention is with 11-15 years olds to encourage lower alcohol consumption. METHODS AND ANALYSIS: This is an individually randomised two-armed trial incorporating a control arm of usual school-based practice and a leaflet on a healthy lifestyle (excl. alcohol), and an intervention arm that combines usual practice with a 30 min brief intervention delivered by school learning mentors and a leaflet on alcohol. At least 30 schools will be recruited from four regions in England (North East, North West, London, Kent and Medway) to follow-up 235 per arm. The primary outcome is total alcohol consumed in the last 28 days, using the 28 day Timeline Follow Back questionnaire measured at the 12-month follow-up. The analysis of the intervention will consider effectiveness and cost-effectiveness. A qualitative study will explore, via 1:1 in-depth interviews with (n=80) parents, young people and school staff, intervention experience, intervention fidelity and acceptability issues, using thematic narrative synthesis to report qualitative data. ETHICS AND DISSEMINATION: Ethical approval was granted by Teesside University. Dissemination plans include academic publications, conference presentations, disseminating to local and national education departments and the wider public health community, including via Fuse, and engaging with school staff and young people to comment on whether and how the project can be improved. TRIAL REGISTRATION TRIAL: ISRCTN45691494; Pre-results.

CT Scans in Young People in Great Britain: Temporal and Descriptive Patterns, 1993-2002.

Background. Although using computed tomography (CT) can be greatly beneficial, the associated relatively high radiation doses have led to growing concerns in relation to potential associations with risk of future cancer. Very little has been published regarding the trends of CT use in young people. Therefore, our objective was to assess temporal and other patterns in CT usage among patients aged under 22 years in Great Britain from 1993 to 2002. Methods. Electronic data were obtained from the Radiology Information Systems of 81 hospital trusts within Great Britain. All included patients were aged under 22 years and examined using CT between 1993 and 2002, with accessible radiology records. Results. The number of CT examinations doubled over the study period. While increases in numbers of recorded examinations were seen across all age groups, the greatest increases were in the older patients, most notably those aged 15-19 years of age. Sixty percent of CT examinations were of the head, with the percentages varying with calendar year and patient age. Conclusions. In contrast to previous data from the North of England, the doubling of CT use was not accompanied by an increase in numbers of multiple examinations to the same individual.

Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study.

BACKGROUND: Although CT scans are very useful clinically, potential cancer risks exist from associated ionising radiation, in particular for children who are more radiosensitive than adults. We aimed to assess the excess risk of leukaemia and brain tumours after CT scans in a cohort of children and young adults. METHODS: In our retrospective cohort study, we included patients without previous cancer diagnoses who were first examined with CT in National Health Service (NHS) centres in England, Wales, or Scotland (Great Britain) between 1985 and 2002, when they were younger than 22 years of age. We obtained data for cancer incidence, mortality, and loss to follow-up from the NHS Central Registry from Jan 1, 1985, to Dec 31, 2008. We estimated absorbed brain and red bone marrow doses per CT scan in mGy and assessed excess incidence of leukaemia and brain tumours cancer with Poisson relative risk models. To avoid inclusion of CT scans related to cancer diagnosis, follow-up for leukaemia began 2 years after the first CT and for brain tumours 5 years after the first CT. FINDINGS: During follow-up, 74 of 178,604 patients were diagnosed with leukaemia and 135 of 176,587 patients were diagnosed with brain tumours. We noted a positive association between radiation dose from CT scans and leukaemia (excess relative risk [ERR] per mGy 0·036, 95% CI 0·005-0·120; p=0·0097) and brain tumours (0·023, 0·010-0·049; p<0·0001). Compared with patients who received a dose of less than 5 mGy, the relative risk of leukaemia for patients who received a cumulative dose of at least 30 mGy (mean dose 51·13 mGy) was 3·18 (95% CI 1·46-6·94) and the relative risk of brain cancer for patients who received a cumulative dose of 50-74 mGy (mean dose 60·42 mGy) was 2·82 (1·33-6·03). INTERPRETATION: Use of CT scans in children to deliver cumulative doses of about 50 mGy might almost triple the risk of leukaemia and doses of about 60 mGy might triple the risk of brain cancer. Because these cancers are relatively rare, the cumulative absolute risks are small: in the 10 years after the first scan for patients younger than 10 years, one excess case of leukaemia and one excess case of brain tumour per 10,000 head CT scans is estimated to occur. Nevertheless, although clinical benefits should outweigh the small absolute risks, radiation doses from CT scans ought to be kept as low as possible and alternative procedures, which do not involve ionising radiation, should be considered if appropriate. FUNDING: US National Cancer Institute and UK Department of Health.