| 1. |
- Duffy, S, et al.
(författare)
-
Estimates of overdiagnosis from two trials of mammographic screening for breast cancer
- 2005
-
Ingår i: Breast Cancer Research. - : Springer Science and Business Media LLC. - 1465-5411 .- 1465-542X. ; 7:6, s. 258-265
-
Tidskriftsartikel (refereegranskat)abstract
- Randomised controlled trials have shown that the policy of mammographic screening confers a substantial and significant reduction in breast cancer mortality. This has often been accompanied, however, by an increase in breast cancer incidence, particularly during the early years of a screening programme, which has led to concerns about overdiagnosis, that is to say, the diagnosis of disease that, if left undetected and therefore untreated, would not become symptomatic. We used incidence data from two randomised controlled trials of mammographic screening, the Swedish Two-county Trial and the Gothenburg Trial, to establish the timing and magnitude of any excess incidence of invasive disease and ductal carcinoma in situ (DCIS) in the study groups, to ascertain whether the excess incidence of DCIS reported early in a screening trial is balanced by a later deficit in invasive disease and provide explicit estimates of the rate of 'real' and non-progressive 'overdiagnosed' tumours from the study groups of the trials. We used a multistate model for overdiagnosis and used Markov Chain Monte Carlo methods to estimate the parameters. After taking into account the effect of lead time, we estimated that less than 5% of cases diagnosed at prevalence screen and less than 1 % of cases diagnosed at incidence screens are being overdiagnosed. Overall, we estimate overdiagnosis to be around 1 % of all cases diagnosed in screened populations. These estimates are, however, subject to considerable uncertainty. Our results suggest that overdiagnosis in mammography screening is a minor phenomenon, but further studies with very large numbers are required for more precise estimation. © 2005 BioMed Central Ltd.
|
|
| 2. |
- Duffy, S. W., et al.
(författare)
-
Overdiagnosis and overtreatment of breast cancer: estimates of overdiagnosis from two trials of mammographic screening for breast cancer
- 2005
-
Ingår i: Breast Cancer Res. - 1465-542X. ; 7:6, s. 258-65
-
Tidskriftsartikel (refereegranskat)abstract
- Randomised controlled trials have shown that the policy of mammographic screening confers a substantial and significant reduction in breast cancer mortality. This has often been accompanied, however, by an increase in breast cancer incidence, particularly during the early years of a screening programme, which has led to concerns about overdiagnosis, that is to say, the diagnosis of disease that, if left undetected and therefore untreated, would not become symptomatic. We used incidence data from two randomised controlled trials of mammographic screening, the Swedish Two-county Trial and the Gothenburg Trial, to establish the timing and magnitude of any excess incidence of invasive disease and ductal carcinoma in situ (DCIS) in the study groups, to ascertain whether the excess incidence of DCIS reported early in a screening trial is balanced by a later deficit in invasive disease and provide explicit estimates of the rate of 'real' and non-progressive 'overdiagnosed' tumours from the study groups of the trials. We used a multistate model for overdiagnosis and used Markov Chain Monte Carlo methods to estimate the parameters. After taking into account the effect of lead time, we estimated that less than 5% of cases diagnosed at prevalence screen and less than 1% of cases diagnosed at incidence screens are being overdiagnosed. Overall, we estimate overdiagnosis to be around 1% of all cases diagnosed in screened populations. These estimates are, however, subject to considerable uncertainty. Our results suggest that overdiagnosis in mammography screening is a minor phenomenon, but further studies with very large numbers are required for more precise estimation.
|
|
| 3. |
- Hofvind, S., et al.
(författare)
-
Influence of review design on percentages of missed interval breast cancers : Retrospective study of interval cancers in a population-based screening program
- 2005
-
Ingår i: Radiology. - : Radiological Society of North America (RSNA). - 0033-8419 .- 1527-1315. ; 237:2, s. 437-443
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To retrospectively investigate whether different review designs have an influence on the estimate of missed interval cancer in a population-based breast cancer screening program. MATERIALS AND METHODS: The Norwegian Breast Cancer Screening Program invites women aged 50-69 years to undergo biennial screening mammography. The current study was part of the evaluation and scientific aspects of the screening program and thus was covered by the general ethical approval of the screening program as a part of the Cancer Registry of Norway. All participants signed an informed consent that specified that data related to their screening visit could be used for evaluation and scientific purposes. Six radiologists (9-34 years of experience in mammography) reviewed previously obtained bilateral two-view screening and diagnostic mammograms of 231 interval cancers, 117 screening-detected cancers, and 373 normal cases. Four review designs were used: individual and paired blinded review and individual and consensus informed review. A five-point interpretation scale was used to reclassify the cancers into missed cancers, minimal signs, and true cancers. The number and proportion of subgroups were estimated with 95% confidence intervals. RESULTS: Of 231 interval cancers, 46 (19.9%) were reclassified as missed cancers with the mixed blinded individual review and 54 (23.4%) were classified as missed cancers with the mixed blinded paired review. Eighty-three cancers (35.9%) were classified as missed cancers with individual informed review, and 78 (33.8%) were classified as missed cancers with consensus informed review. Thirty-nine cancers (16.8%) were reclassified as missed when four or more radiologists assigned a score of 2 or more (probably benign or more suspicious), three cancers (1.3%) were reclassified as missed when a score of 4 or more (probably malignant or more suspicious) was assigned. CONCLUSION: The percentage of interval cancers classified as missed ranged from 1.3% to 35.9% according to review design. To encourage learning, a review protocol should include both blinded and informed designs. © RSNA, 2005.
|
|
| 4. |
- Larsson, LG, et al.
(författare)
-
The Swedish randomised mammography screening trials: analysis of their effect on the breast cancer related excess mortality
- 1996
-
Ingår i: Journal of medical screening. - : SAGE Publications. - 0969-1413 .- 1475-5793. ; 3:3, s. 129-32
-
Tidskriftsartikel (refereegranskat)abstract
- –To apply an indirect method for estimation of the breast cancer related excess mortality in the Swedish randomised mammography screening trials.Setting–Randomised trials on mammography screening have, in Sweden, been performed in the counties of Kopparberg (W) and Östergötland (E), the so called WE study, and in the three largest cities in Sweden, Stockholm (southern part), Gothenburg, and Malmö. An overview of the trials was presented in the Lancet in 1993 and included 156 911 women in the invited group and 125 866 in the control group.Methods–The excess mortality in the breast cancer subgroups was estimated by indirect standardisation using official national cause of death statistics according to Statistics Sweden as a reference. Results—The estimated reduction of the breast cancer related mortality was 24% for the whole group (40–74 years at randomisation). The corresponding figures for the age groups 40–49, 50–59, and 60–69 years were 6%, 28%, and 34% respectively.Conclusion–The results are very similar to those presented earlier based on the traditional comparison of the breast cancer mortality in the invited and in the control group. This analysis further strengthens previous reports on a beneficial effect of mammography screening, which is especially pronounced in the age group 50–69.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Nystrom, L, et al.
(författare)
-
An overview of the Swedish randomised mammography trials: total mortality pattern and the representivity of the study cohorts
- 1996
-
Ingår i: Journal of medical screening. - : SAGE Publications. - 0969-1413 .- 1475-5793. ; 3:2, s. 85-7
-
Tidskriftsartikel (refereegranskat)abstract
- –To analyse the cause of death pattern in the cohorts of women included in the Swedish randomised mammography screening trials by comparing the groups of invited and control women both with each other and with the general population of Swedish women. Setting –Since 1977 four randomised trials of mammography screening have been performed in Sweden: Malmö, Kopparberg and ÖOstergötland (the two county trial), Stockholm, and Gothenburg. Design –Overview of four randomised mammography screening trials. Results –The total numbers of deaths in the invited and control groups respectively were 15 695 and 11 887 corresponding to a relative risk (RR) of 1.00. There were no significant differences between the invited and control groups for cause-specific mortality, except for breast cancer. When the total mortality in the invited and the control groups was compared with that for Swedish women in general the standardised mortality ratio was close to 100. Conclusions –The cause of death pattern in the invited group was, except for breast cancer, very similar to that in the control group, showing that the groups were comparable. Similarly, the total mortality including breast cancer mortality in the control group was almost identical to that in Swedish women in general. The same was true, with the exception of breast cancer, for the invited group. These observations confirm that the trial cohorts are representative of Swedish women and indicate that the quantitative results from these trials may safely be generalised to the Swedish population.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
- Wang, HG, et al.
(författare)
-
Interval cancers in the Norwegian Breast Cancer Screening Program : Frequency, characteristics and use of HRT
- 2001
-
Ingår i: International Journal of Cancer. - 0020-7136 .- 1097-0215. ; 94:4, s. 594-598
-
Tidskriftsartikel (refereegranskat)abstract
- Breast cancers diagnosed between screening examinations among women who attend a breast cancer screening program are defined as interval cancers. The Norwegian Breast Cancer Screening Program started as a pilot project in 1996, and data from the first 2-year interval are available. Our study quantifies interval cancers in the pilot project and explores characteristics and factors that may be associated with interval cancer. Interval cancers in the screening population were identified through the Cancer Registry of Norway. The frequency of invasive interval cancer was calculated as cases per 10,000 screened and as observed/expected ratio. Characteristics of the interval cancers were compared to screening-detected and clinical cancers. Breast density was assessed in a blinded review of 3 categories of screening mammograms. Information on hormone replacement therapy (HRT) use was collected from a questionnaire. The frequency of invasive interval cancers was 18.2 (15.9-20.7) per 10,000 screened and the observed/expected ratio was 0.49 (0.43-0.56). The frequency in the second year of the interval was higher than reported from other programs. The median tumor size of the interval cancers was 19.5 mm and 44.0% of the patients had affected axillary lymph nodes. The interval cancer cases had higher proportions of dense breasts and reported use of HRT compared to screen normal and screening-detected cases. The reported frequency of interval cancers is similar to comparable programs. The interval cancers differed significantly from the cancers detected in the first screening round and were more similar to clinical cancers. Interval cancer was associated with dense breasts and use of HRT. Screening programs must keep these associations in focus. (C) 2001 Wiley-Liss, Inc.
|
|
