Skip header and navigation

Refine By

10 records – page 1 of 1.

Are benefits and harms in mammography screening given equal attention in scientific articles? A cross-sectional study.

https://arctichealth.org/en/permalink/ahliterature77117
Source
BMC Med. 2007;5:12
Publication Type
Article
Date
2007
Author
Jørgensen Karsten Juhl
Klahn Anders
Gøtzsche Peter C
Author Affiliation
The Nordic Cochrane Centre, Rigshospitalet, Blegdamsvej 9, Copenhagen, Denmark. kj@cochrane.dk
Source
BMC Med. 2007;5:12
Date
2007
Language
English
Publication Type
Article
Keywords
Conflict of Interest
Cross-Sectional Studies
Female
Humans
Information Dissemination - methods
Journalism, Medical
Mammography - adverse effects - statistics & numerical data
Mass Screening - adverse effects - statistics & numerical data
Periodicals - statistics & numerical data
Risk assessment
Abstract
BACKGROUND: The CONSORT statement specifies the need for a balanced presentation of both benefits and harms of medical interventions in trial reports. However, invitations to screening and newspaper articles often emphasize benefits and downplay or omit harms, and it is known that scientific articles can be influenced by conflicts of interest. We wanted to determine if a similar imbalance occurs in scientific articles on mammography screening and if it is related to author affiliation. METHODS: We searched PubMed in April 2005 for articles on mammography screening that mentioned a benefit or a harm and that were published in 2004 in English. Data extraction was performed by three independent investigators, two unblinded and one blinded for article contents, and author names and affiliation, as appropriate. The extracted data were compared and discrepancies resolved by two investigators in a combined analysis. We defined three groups of authors: (1) authors in specialties unrelated to mammography screening, (2) authors in screening-affiliated specialties (radiology or breast cancer surgery) who were not working with screening, or authors funded by cancer charities, and (3) authors (at least one) working directly with mammography screening programmes. We used a data extraction sheet with 17 items described as important benefits and harms in the 2002 WHO/IARC-report on breast cancer screening. RESULTS: We identified 854 articles, and 143 were eligible for the study. Most were original research. Benefits were mentioned more often than harms (96% vs 62%, P
PubMed ID
17537243 View in PubMed
Less detail

Biases in estimates of overdetection due to mammography screening.

https://arctichealth.org/en/permalink/ahliterature93535
Source
Lancet Oncol. 2008 Mar;9(3):199-201; author reply 201-2
Publication Type
Article
Date
Mar-2008

Breast screening: the facts--or maybe not.

https://arctichealth.org/en/permalink/ahliterature90270
Source
BMJ. 2009;338:b86
Publication Type
Article
Date
2009
Author
Gøtzsche Peter C
Hartling Ole J
Nielsen Margrethe
Brodersen John
Jørgensen Karsten Juhl
Author Affiliation
Nordic Cochrane Centre, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. pcg@cochrane.dk
Source
BMJ. 2009;338:b86
Date
2009
Language
English
Publication Type
Article
Keywords
Advertising as Topic
Breast Neoplasms - prevention & control
Female
Great Britain
Humans
Mass Screening - adverse effects - methods
Pamphlets
Patient Education as Topic
Notes
Comment In: BMJ. 2009;338:b95719273512
PubMed ID
19174442 View in PubMed
Less detail

The debate on breast cancer screening with mammography is important.

https://arctichealth.org/en/permalink/ahliterature78177
Source
J Am Coll Radiol. 2004 Jan;1(1):8-14
Publication Type
Article
Date
Jan-2004
Author
Gøtzsche Peter C
Author Affiliation
Nordic Cochrane Centre, H:S Rigshospitalet, Copenhagen, Denmark. pcg@cochrane.dk
Source
J Am Coll Radiol. 2004 Jan;1(1):8-14
Date
Jan-2004
Language
English
Publication Type
Article
PubMed ID
17411511 View in PubMed
Less detail

Fungal infection-related mortality versus total mortality as an outcome in trials of antifungal agents.

https://arctichealth.org/en/permalink/ahliterature81104
Source
BMC Med Res Methodol. 2006;6:40
Publication Type
Article
Date
2006
Author
Due Anne K
Johansen Helle K
Gøtzsche Peter C
Author Affiliation
Nordic Cochrane Centre, Rigshospitalet, Dept, 7112, Blegdamsvej 9, DK-2100 København Ø, Denmark. anne.k.due@sol.dk
Source
BMC Med Res Methodol. 2006;6:40
Date
2006
Language
English
Publication Type
Article
Keywords
Antifungal Agents - pharmacology - therapeutic use
Bias (epidemiology)
Cause of Death
Critical Illness - mortality
Humans
Immunocompromised Host
Incidence
Mycoses - complications - drug therapy - mortality
Neoplasms - complications - immunology - mortality
Neutropenia - complications - immunology - mortality
Opportunistic Infections - complications - mortality
Randomized Controlled Trials
Risk
Treatment Outcome
Abstract
BACKGROUND: Disease specific mortality is often used as outcome rather than total mortality in clinical trials. This approach assumes that the classification of cause of death is unbiased. We explored whether use of fungal infection-related mortality as outcome rather than total mortality leads to bias in trials of antifungal agents in cancer patients. METHODS: As an estimate of bias we used relative risk of death in those patients the authors considered had not died from fungal infection. Our sample consisted of 69 trials included in four systematic reviews of prophylactic or empirical antifungal treatment in patients with cancer and neutropenia we have published previously. RESULTS: Thirty trials met the inclusion criteria. The trials comprised 6130 patients and 869 deaths, 220 (25%) of which were ascribed to fungal infection. The relative risk of death was 0.85 (95% CI 0.75-0.96) for total mortality, 0.57 (95% CI 0.44-0.74) for fungal mortality, and 0.95 (95% CI 0.82-1.09) for mortality among those who did not die from fungal infection. CONCLUSION: We could not support the hypothesis that use of disease specific mortality introduces bias in antifungal trials on cancer patients as our estimate of the relative risk for mortality in those who survived the fungal infection was not increased. We conclude that it seems to be reliable to use fungal mortality as the primary outcome in trials of antifungal agents. Data on total mortality should be reported as well, however, to guard against the possible introduction of harmful treatments.
PubMed ID
16907965 View in PubMed
Less detail

[Non-useful cancer survival statistics following the Danish Cancer Control Plan]

https://arctichealth.org/en/permalink/ahliterature91398
Source
Ugeskr Laeger. 2008 Oct 20;170(43):3442; author reply 3442
Publication Type
Article
Date
Oct-20-2008
Author
Gøtzsche Peter C
Source
Ugeskr Laeger. 2008 Oct 20;170(43):3442; author reply 3442
Date
Oct-20-2008
Language
Danish
Publication Type
Article
Keywords
Denmark - epidemiology
Humans
Neoplasms - diagnosis - mortality
Outcome and Process Assessment (Health Care)
Survival Analysis
Notes
Comment On: Ugeskr Laeger. 2008 Sep 22;170(39):3065-918822235
PubMed ID
18979668 View in PubMed
Less detail

Overdiagnosis in publicly organised mammography screening programmes: systematic review of incidence trends.

https://arctichealth.org/en/permalink/ahliterature88450
Source
BMJ. 2009;339:b2587
Publication Type
Article
Date
2009
Author
Jørgensen Karsten Juhl
Gøtzsche Peter C
Author Affiliation
The Nordic Cochrane Centre, Rigshospitalet, Dept 3343, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. kj@cochrane.dk
Source
BMJ. 2009;339:b2587
Date
2009
Language
English
Publication Type
Article
Keywords
Aged
Breast Neoplasms - epidemiology - radiography
Diagnostic Errors
False Positive Reactions
Female
Humans
Incidence
Mammography - standards
Mass Screening - methods
Middle Aged
Abstract
OBJECTIVE: To estimate the extent of overdiagnosis (the detection of cancers that will not cause death or symptoms) in publicly organised screening programmes. DESIGN: Systematic review of published trends in incidence of breast cancer before and after the introduction of mammography screening. DATA SOURCES: PubMed (April 2007), reference lists, and authors. Review methods One author extracted data on incidence of breast cancer (including carcinoma in situ), population size, screening uptake, time periods, and age groups, which were checked independently by the other author. Linear regression was used to estimate trends in incidence before and after the introduction of screening and in older, previously screened women. Meta-analysis was used to estimate the extent of overdiagnosis. RESULTS: Incidence data covering at least seven years before screening and seven years after screening had been fully implemented, and including both screened and non-screened age groups, were available from the United Kingdom; Manitoba, Canada; New South Wales, Australia; Sweden; and parts of Norway. The implementation phase with its prevalence peak was excluded and adjustment made for changing background incidence and compensatory drops in incidence among older, previously screened women. Overdiagnosis was estimated at 52% (95% confidence interval 46% to 58%). Data from three countries showed a drop in incidence as the women exceeded the age limit for screening, but the reduction was small and the estimate of overdiagnosis was compensated for in this review. CONCLUSIONS: The increase in incidence of breast cancer was closely related to the introduction of screening and little of this increase was compensated for by a drop in incidence of breast cancer in previously screened women. One in three breast cancers detected in a population offered organised screening is overdiagnosed.
Notes
Comment In: BMJ. 2009;339:b142519589820
Comment In: BMJ. 2009;339:b325619671607
Comment In: BMJ. 2009;339:b326019671608
Comment In: BMJ. 2009;339:b326219671610
PubMed ID
19589821 View in PubMed
Less detail

Results of the Two-County trial of mammography screening are not compatible with contemporaneous official Swedish breast cancer statistics.

https://arctichealth.org/en/permalink/ahliterature79513
Source
Dan Med Bull. 2006 Nov;53(4):438-40
Publication Type
Article
Date
Nov-2006
Author
Zahl Per-Henrik
Gøtzsche Peter C
Andersen Jannike Mørch
Maehlen Jan
Author Affiliation
Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, 0403, Oslo, Norway. per-henrik.zahl@fhi.no
Source
Dan Med Bull. 2006 Nov;53(4):438-40
Date
Nov-2006
Language
English
Publication Type
Article
Keywords
Bias (epidemiology)
Breast Neoplasms - diagnosis - epidemiology
Female
Humans
Mammography - statistics & numerical data
Mass Screening - statistics & numerical data
Registries
Research Design
Sweden - epidemiology
Abstract
BACKGROUND: National mammography screening programmes are based on the results of randomised trials, but the quality of these trials has recently been questioned. The Swedish Two-County trial reported a 31% reduction in breast cancer mortality and was instrumental for the introduction of screening in many countries. In this trial, official Swedish health registries were used to identify breast cancers and breast cancer deaths in the study population. METHODS: We used data from the same registries to estimate the numbers of breast cancer cases and breast cancer deaths among the included women. RESULTS: Compared to official Swedish statistics we found that 192 breast cancer cases and 43 breast cancer deaths seem to be missing in the main publication of the Two-County trial; we found similar discrepancies in two updates of the trial. These large differences can hardly be explained by random fluctuations in the cancer occurrence. CONCLUSION: The data reported for the Two-County trial are incomplete. Other data indicate that the mortality results in a recent report were flawed.
PubMed ID
17150148 View in PubMed
Less detail

Screening for breast cancer with mammography.

https://arctichealth.org/en/permalink/ahliterature95032
Source
Cochrane Database Syst Rev. 2009;(4):CD001877
Publication Type
Article
Date
2009
Author
Gøtzsche Peter C
Nielsen Margrethe
Author Affiliation
The Nordic Cochrane Centre, Rigshospitalet, Blegdamsvej 9, 3343, Copenhagen, Denmark, 2100.
Source
Cochrane Database Syst Rev. 2009;(4):CD001877
Date
2009
Language
English
Publication Type
Article
Abstract
BACKGROUND: A variety of estimates of the benefits and harms of mammographic screening for breast cancer have been published and national policies vary. OBJECTIVES: To assess the effect of screening for breast cancer with mammography on mortality and morbidity. SEARCH STRATEGY: We searched PubMed (November 2008). SELECTION CRITERIA: Randomised trials comparing mammographic screening with no mammographic screening. DATA COLLECTION AND ANALYSIS: Both authors independently extracted data. Study authors were contacted for additional information. MAIN RESULTS: Eight eligible trials were identified. We excluded a biased trial and included 600,000 women in the analyses. Three trials with adequate randomisation did not show a significant reduction in breast cancer mortality at 13 years (relative risk (RR) 0.90, 95% confidence interval (CI) 0.79 to 1.02); four trials with suboptimal randomisation showed a significant reduction in breast cancer mortality with an RR of 0.75 (95% CI 0.67 to 0.83). The RR for all seven trials combined was 0.81 (95% CI 0.74 to 0.87). We found that breast cancer mortality was an unreliable outcome that was biased in favour of screening, mainly because of differential misclassification of cause of death. The trials with adequate randomisation did not find an effect of screening on cancer mortality, including breast cancer, after 10 years (RR 1.02, 95% CI 0.95 to 1.10) or on all-cause mortality after 13 years (RR 0.99, 95% CI 0.95 to 1.03).Numbers of lumpectomies and mastectomies were significantly larger in the screened groups (RR 1.31, 95% CI 1.22 to 1.42) for the two adequately randomised trials that measured this outcome; the use of radiotherapy was similarly increased. AUTHORS' CONCLUSIONS: Screening is likely to reduce breast cancer mortality. As the effect was lowest in the adequately randomised trials, a reasonable estimate is a 15% reduction corresponding to an absolute risk reduction of 0.05%. Screening led to 30% overdiagnosis and overtreatment, or an absolute risk increase of 0.5%. This means that for every 2000 women invited for screening throughout 10 years, one will have her life prolonged and 10 healthy women, who would not have been diagnosed if there had not been screening, will be treated unnecessarily. Furthermore, more than 200 women will experience important psychological distress for many months because of false positive findings. It is thus not clear whether screening does more good than harm. To help ensure that the women are fully informed of both benefits and harms before they decide whether or not to attend screening, we have written an evidence-based leaflet for lay people that is available in several languages on www.cochrane.dk.
Notes
UpdateOf: Cochrane Database Syst Rev. 2006;(4):CD00187717054145
PubMed ID
19821284 View in PubMed
Less detail

Spontaneous improvement in randomised clinical trials: meta-analysis of three-armed trials comparing no treatment, placebo and active intervention.

https://arctichealth.org/en/permalink/ahliterature90559
Source
BMC Med Res Methodol. 2009;9:1
Publication Type
Article
Date
2009
Author
Krogsbøll Lasse Theis
Hróbjartsson Asbjørn
Gøtzsche Peter C
Author Affiliation
The Nordic Cochrane Centre, Rigshospitalet, Dept, 3343, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. lassetk@hotmail.com
Source
BMC Med Res Methodol. 2009;9:1
Date
2009
Language
English
Publication Type
Article
Keywords
Adolescent
Child
Child, Preschool
Cluster analysis
Computer simulation
Female
Humans
Logistic Models
Male
Patient Selection
Placebos
Poisson Distribution
Pregnancy
Randomized Controlled Trials as Topic
Treatment Outcome
Abstract
BACKGROUND: It can be challenging for patients and clinicians to properly interpret a change in the clinical condition after a treatment has been given. It is not known to which extent spontaneous improvement, effect of placebo and effect of active interventions contribute to the observed change from baseline, and we aimed at quantifying these contributions. METHODS: Systematic review and meta-analysis, based on a Cochrane review of the effect of placebo interventions for all clinical conditions. We selected all trials that had randomised the patients to three arms: no treatment, placebo and active intervention, and that had used an outcome that was measured on a continuous scale or on a ranking scale. Clinical conditions that had been studied in less than three trials were excluded. RESULTS: We analysed 37 trials (2900 patients) that covered 8 clinical conditions. The active interventions were psychological in 17 trials, physical in 15 trials, and pharmacological in 5 trials. Overall, across all conditions and interventions, there was a statistically significant change from baseline in all three arms. The standardized mean difference (SMD) for change from baseline was -0.24 (95% confidence interval -0.36 to -0.12) for no treatment, -0.44 (-0.61 to -0.28) for placebo, and -1.01 (-1.16 to -0.86) for active treatment. Thus, on average, the relative contributions of spontaneous improvement and of placebo to that of the active interventions were 24% and 20%, respectively, but with some uncertainty, as indicated by the confidence intervals for the three SMDs. The conditions that had the most pronounced spontaneous improvement were nausea (45%), smoking (40%), depression (35%), phobia (34%) and acute pain (25%). CONCLUSION: Spontaneous improvement and effect of placebo contributed importantly to the observed treatment effect in actively treated patients, but the relative importance of these factors differed according to clinical condition and intervention.
PubMed ID
19123933 View in PubMed
Less detail

10 records – page 1 of 1.