Table 1.

Study characteristics Declaration of interests

	Studies	Study populations	Patients with breast cancer	Patients with known breast cancer, n (%)
Total	83	91	26 788	24 213 (90.4%)
Race
Black†	75	76	18 805	16 669 (88.6%)
Non-black‡	8	15	7983	7544 (94.5%)
Region or country
Western Africa	48	49
Nigeria	36	37	8623	8407 (97.5%)
Benin	2	2	204	204 (100%)
Ghana	5	5	1969	1191 (60.5%)
Mali	2	2	324	324 (100%)
Other§	3	3	797	719 (90.2%)
Eastern or middle Africa	19	19
Tanzania	5	5	1310	1151 (87.7%)
Kenya	2	2	287	157 (54.7%)
Ethiopia	3	3	1267	841 (66.4%)
Madagascar	2	2	289	233 (80.6%)
Uganda	3	3	562	502 (89.3%)
Other¶	4	4	445	302 (67.9%)
Southern Africa	16	23
South Africa	16	23	10 711	10 182 (95.1%)
Study design
Convenience case series	48	55	10 780	9788 (90.8%)
Consecutive case series	35	36	16 008	14 425 (90.1%)
Study population
Urban	27	34	15 571	14 208 (91.2%)
Mixed (rural and urban)	56	57	11 217	10 005 (89.2%)
Type of health facility
Tertiary, secondary, or primary‖	9	12	1639	1503 (91.7%)
Tertiary	72	77	24 742	22 399 (90.5%)
Not reported in original study	2	2	407	311 (76.4%)
Age at diagnosis (years)**
<45 years	28	29	5475	4840 (88.4%)
>45 to <50 years	36	37	7882	7218 (91.6%)
>50 years	16	22	11 056	9841 (89.0%)
Not reported in original study	3	3	2375	2314 (97.4%)
Year of diagnosis††
Before 1980	11	16	3971	3782 (95.2%)
1980–1999	32	34	11 125	10 737 (96.5%)
2000 or after	33	33	8648	6733 (77.8%)
Not reported in original study	7	8	3044	2961 (97.3%)
Staging methods
Clinical and imaging	25	26	10 416	9516 (91.4%)
Clinical only	10	10	975	967 (99.2%)
Not reported in original study	48	55	15 397	13 730 (89.2%)
Staging classification
TNM	50	57	20 388	18 048 (88.5%)
Manchester	11	11	1436	1426 (99.3%)
Not reported in original study	22	23	4964	4739 (95.5%)
Study quality scores‡‡
>23 (highest quality)	12	12	4067	3569 (87.8%)
22–20	26	27	6181	5721 (92.6%)
19–17	31	38	14 541	13 327 (91.7%)
<17 (lowest quality)	14	14	1999	1596 (79.8%)

Data are n or n (%). TNM=Tumour, Lymph Node, and Metastasis staging system.

^*Five studies provided separate estimates for different subsets of participants (ie, for pregnant or lactating and non-pregnant or non-lactating women²⁷ or different ethnic groups^12,28–30).

^†Includes seven southern African studies^{12,28–30,39–41} that reported estimates for black women only; one southern African study¹⁸ that presented only an overall (all ethnic groups combined) estimate, but reported that >80% of their study population was black; nine studies^{5,37,38,42–47} from western and eastern Africa that were done exclusively in black women, as well as the remaining 58 studies from these two regions that did not report on race, but were assumed to have been done in predominantly black women (ie, >80% black; see appendix p 14), which corresponded to 76 study population groups because one Nigerian study²⁷ presented separate estimates for pregnant or lactating and non-pregnant or non-lactating women (appendix p 14).

^‡Includes 15 southern African study population groups: four studies^14,48–50 that did not report on race but were assumed to be predominantly non-black, four studies^36,51–53 that present only overall estimates but reported an ethnically mixed population with ≤80% being black, and four multi-ethnic studies^12,28–30 that together reported separate estimates for seven non-black population groups (appendix p 14).

^§Includes one study from Guinea (178 cases, 124 cases with known stage), one from Niger (146 cases, 146 cases with known stage), and one from Senegal (473 cases, 449 cases with known stage).

^¶Includes one study from Rwanda (145 cases, seven cases with known stage), one from Zimbabwe (84 cases, 79 cases with known stage), one from Eritrea (82 cases, 82 cases with known stage), and one from Democratic Republic of the Congo (formerly known as Zaire; 134 cases, 134 cases with known stage).

^‖All studies that recruited participants from secondary and primary health centres also included a tertiary centre.

^**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. The three studies in which age was not reported in the original category did not provide sufficient information to allow their allocation into one of the three age categories: Ajekigbe⁵⁴ reported that 50.8% of the participants were aged <50 years; Amir and colleagues⁵⁵ reported that 90% of the participants were aged <50 years; and Pegoraro and colleagues³⁶ reported that 50% were between aged 45–64 years (appendix p 14).

^††Middle year of the time interval during which patients were recruited.

^‡‡Categories represent quartiles of the overall score distribution (appendix p 9).