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Data source: Concept, design, analysis.

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Presentation on theme: "Data source: Concept, design, analysis."— Presentation transcript:

1 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Women offered screening mammography experience a higher rate of diagnosis of invasive breast cancer, without a corresponding reduction in subsequent symptomatic breast cancer. OR in other words, Many screen-detected invasive cancers would not have grown. Jayant S Vaidya

2 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Screening mammography aims to detect breast cancer at an earlier more “curable” stage. Therefore, in the years immediately after screening, the women who have been screened should enjoy a lower incidence of breast cancer.

3 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Data source: These graphs are plotted in a rather unusual way

4 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation In Scotland, some regions are attended by a screening van for 1 year every 3 years, with no screening occurring in the interim 2 years. For example, in the regions of Borders, Fife and Forth valley, the screening van –visits every 3 years from 1990, 1991 and 1992, respectively. In Fife, the screening year corresponds most closely to the calendar year

5 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Fife

6 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Fife Incidence is higher in the screening year because of detection of “earlier” cancers

7 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Fife Incidence is higher in the screening year because of detection of “earlier” cancers

8 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Borders Incidence is higher in the screening year because of detection of “earlier” cancers But the incidence in the interim years is not lowered (compared with that before screening started) Despite the “earlier” detection of cancers in the screening year –the “later” cancers are not reduced

9 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Forth valley Incidence is higher in the screening year because of detection of “earlier” cancers But the incidence in the interim years is not lowered (compared with that before screening started) Despite the “earlier” detection of cancers in the screening year –the “later” cancers are not reduced Breast Cancer incidence : age standardised rate

10 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Scotland Each line represents a single cohort of women

11 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Scotland

12 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Scotland

13 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Scotland

14 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Scotland Incidence of breast cancer in those too young to have screening has remained constant

15 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Scotland Incidence of breast cancer in those too old to have screening has remained constant –this group (light brown line) probably had one round of screening

16 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Scotland This group had the benefit of the whole package of screening for 5 rounds over 15 years

17 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Scotland Screening stopped when they reached the age group of between 2001 to 2003 Screening stopped

18 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Invasive breast cancer incidence in Scotland In 2004, despite NOT screening, the incidence remains high – and much higher than that 20, or 10 years ago Screening stopped

19 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation Women who undergo regular screening mammography raise their incidence of invasive breast cancer by 30% to 60%. In the years between consecutive screens, the incidence is not correspondingly reduced. And, after stopping screening, rather than enjoying a reduced incidence, these women continue to experience a higher risk of invasive breast cancer Conclusion

20 Data source: Concept, design, analysis and graphs by Jayant S Vaidya. Submitted for publication. Confidential and not for citation These data demonstrate the dormancy of invasive breast cancer very elegantly, in the real world. It suggests that a much higher (up to a third) than currently believed proportion invasive breast cancers detected by screening mammography would not have grown. Further research should focus on studying how so many women manage to keep their invasive cancers in a state of dormancy Conclusion


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