Abstract S1-10: Disparities in the estimates of benefits and harms from mammography: Are the numbers really different?

It is generally accepted that screening with mammography prevents deaths from breast cancer, although debate continues about the absolute size of the mortality benefit, and the concomitant risks associated with screening. A number of recent observational studies have claimed to find low rates of benefit in terms of reducing mortality rates or late stage disease, and high rates of overdiagnosis, defined as the diagnosis by screening of cancer which would not have been diagnosed in the patient's lifetime if screening had not taken place. These publications have achieved a high profile in the mass media and stimulated further debate. We review the apparent disparities between different reviews of the effects of mammography screening on mortality from breast cancer and on overdiagnosis. The four major reviews are the UK Independent Review, the Nordic Cochrane review, the US Preventive Services Task Force (USPSTF) review, and the EUROSCREEN review. The estimated number needed to screen/invite to prevent one death from breast cancer ranges from 111 to 2000, almost a 20-fold range. The estimated number required varies by age group, whether the intervention described is actual screening or invitation to screening, follow-up time and other factors. To assess whether these represent genuine disagreements or whether the differences are mainly due to such factors as follow-up time and target population, we converted all four to pertain to the same scenario as used in the UK Independent Review, that is to the effect of screening for 20 years from age 50 to 69 on breast cancer mortality in ages 55-79, in a UK population. When all four reviews are converted to the UK review scenario, the range of absolute benefits is now only 2.5-fold rather than 20-fold. Thus, the differences between the reviews with respect to the absolute breast cancer mortality reduction are almost entirely due to expressing the same basic result relative to different denominators, choice of population mortality rates, etc. Thus, the so-called controversy over the benefit of mammography screening as estimated from the trials is largely contrived. When expressed relative to the same denominator, with the same screening and follow-up periods, and using the same absolute mortality rates, absolute benefit estimates are all of the same order of magnitude, and all indicate a substantial reduction in breast cancer mortality with screening. While there are genuine disagreements about overdiagnosis, methods which adjust for lead time and underlying incidence trends yield estimates which are modest and are outweighed by the mortality benefit.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S1-10.

Intra- and inter-rater reliability of jumping mechanography muscle function assessments

Muscle function can be assessed through jumping mechanography, where portable ground reaction force plates collect dynamic information as a subject jumps. The aim of this study was to assess both intra- and inter- rater reliability of jumping mechanography. Ten healthy adults underwent 3 sets of testing (collected by 3 different raters) at two separate sessions, one week apart. They performed a number of tests in each session: multiple one-legged hopping (M1LH; on right and left legs) and single two-legged jumps (S2LJ; with or without arm swing). The S2LJ assessed variables of power per body mass, jump height, velocity and efficiency; whereas, M1LH assessed maximum force per body mass and stiffness. Inter-rater coefficients of variation (CV) were less than 0.6% and 2.6% for the S2LJ and M1LH, respectively, for the primary outcome variables of power/body mass and force/body mass. Analyzing intra-rater results also produced CVs less than 5.3% for all variables. The present study reports that the Leonardo ground reaction force plate system yields reproducible results between sessions, without significant contribution of variability from the test operator. Jumping mechanography is an easy, safe and reliable method for the assessment of lower limb musculoskeletal function.

In vivo glutathione levels in young persons with bipolar disorder: a magnetic resonance spectroscopy study

Oxidative stress has recently been reported to assume a significant role in the pathophysiology of bipolar disorder. Several studies have demonstrated the replenishment of glutathione (GSH) diminishes oxidative cellular damage and ameliorates depressive symptoms in this disorder. Whilst the mechanism by which GSH exerts any clinical effect is unknown it has been proposed that it involves the bolstering of antioxidant defences by increasing the bioavailability of GSH, which in turn reverses clinical symptoms of depression. Such a proposal is predicated on the implicit assumption that GSH is diminished in these patients prior to GSH supplementation. However hitherto no study has reported in vivo measures of GSH in patients with bipolar disorder. Using magnetic resonance spectroscopy we obtained in vivo measures of GSH in young people with bipolar disorder and contrasted these with matched healthy controls. Young people with bipolar disorder were found to have no diminution in baseline GSH concentration and, furthermore, no significant correlations were found between GSH and clinical scores of depression or mania. The results do not support the hypothesis that oxidative stress is involved in the primary pathophysiology of bipolar disorder.

Does use of a World Health Organization obstetric safe surgery checklist improve communication between obstetricians and anaesthetists? A retrospective study of 389 caesarean sections

We evaluated the impact of the World Health Organization Obstetric Safe Surgery Checklist (WHO Checklist) on perioperative communication between anaesthetists and obstetricians by performing a retrospective audit in a Teaching hospital in London, UK. Caesarean section births from February to March 2009 and April to May 2011 were studied. Caesarean section notes from obstetricians and anaesthetists managing the same woman during the study period were reviewed. Grading differences between obstetricians and anaesthetists before and after checklist introduction were evaluated. Communication failure (where obstetricians and anaesthetists had documented different caesarean section grades [level of urgency]) and good communication (where obstetricians and anaesthetists had documented the same caesarean section grade) were observed. In total, 195 caesarean sections before introduction of the WHO safe surgery checklist and 194 caesarean sections after checklist introduction were studied. Grading differences occurred in 24.1% of caesarean sections without checklists compared with 10.3% with checklists (P < 0.001). During emergency caesarean section alone, grading differences between obstetricians and anaesthetists were smaller, although this was not significant (P = 0.222). We conclude that implementation of a WHO Obstetric Safe Surgery checklist improves the communication of caesarean section grade (urgency) between obstetricians and anaesthetists.