Table 2.
Sources of between-population heterogeneity in the percentage of late-stage breast cancer (stages III/IV) from meta-regression analyses
| Patients with breast cancer, n | All study populations
|
Black populations only
|
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Unadjusted analysis |
Region and race adjusted
analysis |
Fully-adjusted analysis*
|
Unadjusted analysis |
Fully-adjusted analysis†
|
|||||||
| AD (%) | 95% Cl | AD (%) | 95% Cl | AD (%) | 95% Cl | AD (%) | 95% Cl | AD (%) | 95% Cl | ||
| Region, race‡ | |||||||||||
|
| |||||||||||
| West Africa, black | 10845 | 0 (ref) | ‥ | ‥ | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ |
| East Africa, black | 3186 | −0.2 | −6.8 to 6.4 | ‥ | ‥ | −3.0 | −9.2 to 3.2 | −0.2 | −6.6 to 6.3 | −3.3 | −9.5 to 2.9 |
| Southern Africa, black | 2638 | 0.1 | −9.0 to 9.3 | ‥ | ‥ | 8.6 | −2.0 to 19.1 | 0.1 | −8.9 to 9.1 | 5.8 | −5.9 to 17.5 |
| Southern Africa, non-black | 7544 | −25.5 | −32.6 to −18.3 | ‥ | ‥ | −18.1 | −28.2 to −8.0 | ‥ | ‥ | ‥ | ‥ |
|
| |||||||||||
| Study design | |||||||||||
|
| |||||||||||
| Convenience case series | 14425 | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ |
| Consecutive case series | 9788 | −6.5 | −12.9 to −0.4 | −0.6 | −6.1 to 4.9 | −2.0 | −7.1 to 3.1 | −2.2 | −7.9 to 3.6 | −2.6 | −8.0 to 2.8 |
|
| |||||||||||
| Study population | |||||||||||
|
| |||||||||||
| Urban | 14208 | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ |
| Mixed (rural and urban) | 10 005 | 16.3 | 10.6 to 22.0 | 10.7 | 3.4 to 17.9 | 12.9 | 5.5 to 20·3 | 7.7 | 1.7 to 13.7 | 13.2 | 5.7 to 20.7 |
|
| |||||||||||
| Facility type | |||||||||||
|
| |||||||||||
| Tertiary | 22399 | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ |
| Tertiary, secondary, or primary | 1503 | −3.7 | −13.2 to 5.8 | −1.2 | −8.8 to 6.4 | −1.9 | −9.1 to 5.4 | −3.2 | −11.5 to 5.1 | −1.4 | −9.5 to 6.6 |
| Not reported in original study | 311 | −8.8 | −30.5 to 12.9 | 14.8 | −3.4 to 32.9 | 10.1 | −0.8 to 28.3 | ‥ | ‥ | ‥ | ‥ |
|
| |||||||||||
| Age at diagnosis (years)§ | |||||||||||
|
| |||||||||||
| <45 years | 4840 | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ |
| >45 to <50 years | 7218 | 0.8 | −6.0 to 7.8 | 0.3 | −5.5 to 6.0 | 3.9 | −2.0 to 9.9 | −0.3 | −6.2 to 5.6 | 3.9 | −2.3 to 10.1) |
| >50 years | 9841 | −13.2 | −21.2 to −5.3 | −6.2 | −14.4 to 2.0 | −1.7 | −9.9 to 6.4 | −3.9 | −12.0 to 4.1 | 1.8 | −8.9 to 12.4 |
| Not reported in original study | 2314 | 12.0 | −4.4 to 28.5 | 17.4 | 3.8 to 31.1 | 20.6 | 6.4 to 34.8 | 14.6 | −1.3 to 30.6 | 20.4 | 4.8 to 36.1 |
|
| |||||||||||
| Year of diagnosis¶ | |||||||||||
|
| |||||||||||
| Before 1980 | 3782 | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ |
| 1980–1999 | 10737 | 4.8 | −4.3 to 13.9 | −3.0 | −10.6 to 4.6 | −5.2 | −12.6 to 2.2 | −4.7 | −13.1 to 3.7 | −6.8 | −15.5 to 1.9 |
| 2000 or after | 6733 | 4.3 | −5.0 to 13.5 | −6.2 | −14.2 to 1.8 | −8.5 | −16.1 to −1.0 | −8.4 | −16.8 to −0.1 | −10.5 | −19.3 to −1.5 |
| Not reported in original study | 2961 | −6.5 | −19.9 to 6.9 | −7.3 | −18.2 to 3.6 | −8.5 | −19.0 to 2.1 | −16.5 | −29.7 to −3.3 | −12.5 | −25.9 to 1.8 |
|
| |||||||||||
| Staging methods | |||||||||||
|
| |||||||||||
| Clinical and imaging | 9516 | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ | 0 (ref) | ‥ |
| Clinical only | 967 | 5.0 | −6.4 to 16.4 | 2.3 | −7.0 to 11.6 | −1.4 | −10.4 to 7.6 | 3.0 | −5.9 to 11.9 | −1.3 | −10.3 to 7.8 |
| Not reported in original study | 13730 | 0.2 | −7.1 to 7.4 | 3.0 | 2.7 to 8.8 | 3.2 | −2.3 to 8.7 | 4.0 | −1.9 to 10.0 | 4.1 | −1.7 to 9.8 |
|
| |||||||||||
| Staging classification | |||||||||||
|
| |||||||||||
| TNM | 18048 | 0 (ref) | ‥ | 0 (ref) | ‥ | ‥ | ‥ | ‥ | ‥ | ‥ | ‥ |
| Manchester | 1426 | 2.4 | −7.6 to 12.5 | −3.7 | −12.1 to 4.6 | ‥ | ‥ | ‥ | ‥ | ‥ | ‥ |
| Not reported in original study | 4739 | 3.1 | −4.5 to 10.7 | −0.8 | −7.0 to 5.5 | ‥ | ‥ | ‥ | ‥ | ‥ | ‥ |
|
| |||||||||||
| Study quality scores‖ | ‥ | ‥ | ‥ | ‥ | ‥ | ‥ | |||||
|
| |||||||||||
| >23 (highest quality) | 3569 | 0 (ref) | ‥ | 0 (ref) | ‥ | ‥ | ‥ | ‥ | ‥ | ‥ | ‥ |
| 22–20 | 5721 | −2.1 | −12.7 to 8.5 | −0.1 | −8.5 to 8.3 | ‥ | ‥ | ‥ | ‥ | ‥ | ‥ |
| 19–17 | 13327 | −1.1 | −11.2 to 9.0 | 2.1 | −5.9 to 10.1 | ‥ | ‥ | ‥ | ‥ | ‥ | ‥ |
| <17 (lowest quality) | 1596 | 0.7 | −11.5 to 12.9 | 2.9 | −6.9 to 12.6 | ‥ | ‥ | ‥ | ‥ | ‥ | ‥ |
Data are n, absolute difference (%), or 95% Cl. Ref= reference category. AD=absolute difference. TNM=Tumour, Lymph Node, and Metastasis staging system.
Adjusted for all other variables, except for staging classification and study quality because of concerns of overadjustment,
Adjusted for all other variables, except region or race, staging classification, and study quality.
The study population was classified as black if 80% of participants or more were black (appendix p 14, figure 3).
Mean or median age at breast cancer diagnosis. If only age categories were reported mean or median age was estimated from the mid-point and the reported number in each age category.
Taken as the middle year of the period during which patient recruitment took place.
Categories defined using quartiles of the overall score distribution. Analyses were not further adjusted for the other variables in the table because most of them were integrated into the study quality scores (appendix p 9).