Ten years of breast screening in the Screening Mammography Program of British Columbia, 1988–97
Bibliographic record
Abstract
OBJECTIVES: To evaluate 10 years outcomes of the Screening Mammography Program of British Columbia (SMPBC) and determine if breast screening targets were being achieved among women aged 40-80+ years. SETTING: Organised breast screening programme in British Columbia, Canada. METHODS: Rates of participation, abnormal referral, cancer detection, and interval cancer were calculated for asymptomatic women receiving an SMPBC mammography from 1988-97. RESULTS: 895,849 screening mammographies were provided to 335,433 women. 51.3% of women were age 50-69 years. Abnormalities were identified on 57,454 screens (6.4%) from which 3304 cancers were detected. Abnormal call rates were higher on first (9.8%), compared with subsequent screens (4.4%) and declined with age: 7.7% at age < 40 to 5.4% for age 70-79 years. Cancer detection rates were higher on first (5.0 per 1000) compared with subsequent screens (2.8 per 1000) and increased smoothly with age from 1.4 to 8.2 per 1000 from age < 40 to age 80 years and older. Twenty per cent of cancers were non-invasive. The median size of invasive cancers was 14 mm and 81% had no axillary lymph node metastases. The 12 month interval cancer rate was 0.6 per 1000 and did not vary significantly with age or screening history. The prevalence to expected incidence ratio was 3.1 for women age 50-79 years. CONCLUSION: Across a broad range of ages, surrogate indices of screening mammography success have been achieved in a population based, North American, organised breast cancer screening programme.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".