Mette Kalager

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BACKGROUND A challenge in quantifying the effect of screening mammography on breast-cancer mortality is to provide valid comparison groups. The use of historical control subjects does not take into account chronologic trends associated with advances in breast-cancer awareness and treatment. METHODS The Norwegian breast-cancer screening program was started(More)
IMPORTANCE Colorectal cancer is a major health burden. Screening is recommended in many countries. OBJECTIVE To estimate the effectiveness of flexible sigmoidoscopy screening on colorectal cancer incidence and mortality in a population-based trial. DESIGN, SETTING, AND PARTICIPANTS Randomized clinical trial of 100,210 individuals aged 50 to 64 years,(More)
MAIN RECOMMENDATIONS The following recommendations for post-polypectomy endoscopic surveillance should be applied only after a high quality baseline colonoscopy with complete removal of all detected neoplastic lesions.1 In the low risk group (patients with 1 - 2 tubular adenomas < 10 mm with low grade dysplasia), the ESGE recommends participation in(More)
BACKGROUND Precise quantification of overdiagnosis of breast cancer (defined as the percentage of cases of cancer that would not have become clinically apparent in a woman's lifetime without screening) due to mammography screening has been hampered by lack of valid comparison groups that identify incidence trends attributable to screening versus those due(More)
BACKGROUND AND STUDY AIMS Screening colonoscopy for colorectal cancer (CRC) is recommended in several countries, but uptake rates are often low. Fear of pain and also time-consuming costly sedation are barriers for colonoscopy, and thus development of colonoscopy equipment that decreases patient discomfort is worthwhile. This randomized controlled trial(More)
BACKGROUND Cancer screening has the potential to prevent or reduce incidence and mortality of the target disease, but may also be harmful and have unwanted side-effects. METHODS This review explains the basic principles of cancer screening, common pitfalls in evaluation of effectiveness and harms of screening, and summarizes the evidence for effects and(More)
OBJECTIVE To compare the prognosis in women with interval breast cancer (cancer detected after a normal screening mammogram and before the next scheduled mammogram) with breast cancer detected among women not yet invited to mammography screening (non-screened). DESIGN Population based observational study. SETTING Norwegian breast cancer screening(More)
Mammography screening reduces breast cancer mortality through earlier diagnosis but may convey further benefit if screening is associated with optimized treatment through multidisciplinary medical care. In Norway, a national mammography screening program was introduced among women aged 50 to 69 years during 1995/6 to 2004. Also during this time,(More)
IMPORTANCE Although some countries have implemented widespread colonoscopy screening, most European countries have not introduced it because of uncertainty regarding participation rates, procedure-related pain and discomfort, endoscopist performance, and effectiveness. To our knowledge, no randomized trials on colonoscopy screening currently exist. (More)
Background Effective breast cancer screening should detect early-stage cancer and prevent advanced disease. Objective To assess the association between screening and the size of detected tumors and to estimate overdiagnosis (detection of tumors that would not become clinically relevant). Design Cohort study. Setting Denmark from 1980 to 2010. (More)