Table 1: Characteristics of study population.
| Stage of cancer; no. (%) of patients* |
|||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| All stages n = 2927 |
Stage 0 n = 424 |
Stage I n = 1118 |
Stage II n = 938 |
Stage III n = 233 |
Stage IV n = 123 |
Unknown n = 91 |
|||||||||||||
| % of all patients |
100 |
14 |
38 |
32 |
8 |
4 |
3 |
||||||||||||
| Sex, female |
2909 |
(99) |
422 |
(>99) |
1116 |
(>99) |
933 |
(99) |
229 |
(98) |
122 |
(99) |
87 |
(96) |
|||||
| Age at diagnosis |
|||||||||||||||||||
| Median (range) |
61 |
(27–102) |
58 |
(28–94) |
62 |
(29–98) |
58 |
(27–101) |
59 |
(30–95) |
64 |
(35–96) |
74 |
(39–102) |
|||||
| < 40 |
127 |
(4) |
6 |
(1) |
38 |
(3) |
62 |
(7) |
15 |
(6) |
5 |
(4) |
1 |
(1) |
|||||
| 40–49 |
538 |
(18) |
100 |
(24) |
176 |
(16) |
201 |
(21) |
46 |
(20) |
9 |
(7) |
6 |
(7) |
|||||
| 50–59 |
719 |
(25) |
124 |
(29) |
261 |
(23) |
226 |
(24) |
62 |
(27) |
33 |
(27) |
13 |
(14) |
|||||
| 60–69 |
660 |
(23) |
95 |
(22) |
290 |
(26) |
185 |
(20) |
40 |
(17) |
29 |
(24) |
21 |
(23) |
|||||
| 70–79 |
583 |
(20) |
74 |
(17) |
267 |
(24) |
164 |
(17) |
35 |
(15) |
23 |
(19) |
20 |
(22) |
|||||
| ≥ 80 |
300 |
(10) |
25 |
(6) |
86 |
(8) |
100 |
(11) |
35 |
(15) |
24 |
(20) |
30 |
(33) |
|||||
| Margin status |
|||||||||||||||||||
| Positive |
123 |
(4) |
14 |
(3) |
20 |
(2) |
39 |
(4) |
26 |
(11) |
15 |
(12) |
9 |
(10) |
|||||
| Negative |
2356 |
(80) |
371 |
(88) |
990 |
(89) |
795 |
(85) |
168 |
(72) |
32 |
(26) |
0 |
(0) |
|||||
| Close |
165 |
(6) |
29 |
(7) |
56 |
(5) |
61 |
(7) |
16 |
(7) |
3 |
(2) |
0 |
(0) |
|||||
| Unknown |
283 |
(10) |
10 |
(2) |
52 |
(5) |
43 |
(5) |
23 |
(10) |
73 |
(59) |
82 |
(90) |
|||||
| Size of tumour, cm |
|||||||||||||||||||
| Median (range) |
1.7 |
(0.1–9.9) |
1.5 |
(0.1–9.9) |
1.2 |
(0.1–2.0) |
2.5 |
(0.1–9.9) |
5.4 |
(0.1–9.9) |
4.3 |
(0.4–9.9) |
1.3 |
(1.1–1.5) |
|||||
| < 1.0 |
529 |
(18) |
122 |
(29) |
370 |
(33) |
27 |
(3) |
8 |
(3) |
2 |
(2) |
0 |
(0) |
|||||
| 1.0–2.0 |
1110 |
(38) |
139 |
(33) |
708 |
(63) |
227 |
(24) |
20 |
(9) |
14 |
(11) |
2 |
(2) |
|||||
| 2.1–5.0 |
822 |
(28) |
90 |
(21) |
0 |
(0) |
628 |
(67) |
70 |
(30) |
34 |
(28) |
0 |
(0) |
|||||
| > 5.0 |
204 |
(7) |
34 |
(8) |
0 |
(0) |
19 |
(2) |
115 |
(49) |
36 |
(29) |
0 |
(0) |
|||||
| Unknown |
262 |
(9) |
39 |
(9) |
40 |
(4) |
37 |
(4) |
20 |
(9) |
37 |
(30) |
89 |
(98) |
|||||
| ER status |
|||||||||||||||||||
| Positive |
1920 |
(66) |
30 |
(7) |
943 |
(84) |
707 |
(75) |
165 |
(71) |
63 |
(51) |
12 |
(13) |
|||||
| Negative |
457 |
(16) |
13 |
(3) |
139 |
(12) |
219 |
(23) |
57 |
(24) |
26 |
(21) |
3 |
(3) |
|||||
| Unknown |
550 |
(19) |
381 |
(90) |
36 |
(3) |
12 |
(1) |
11 |
(5) |
34 |
(28) |
76 |
(84) |
|||||
| Grade |
|||||||||||||||||||
| 1 |
784 |
(27) |
85 |
(20) |
487 |
(44) |
177 |
(19) |
22 |
(9) |
9 |
(7) |
4 |
(4) |
|||||
| 2 |
1050 |
(36) |
152 |
(36) |
413 |
(37) |
361 |
(38) |
82 |
(35) |
35 |
(28) |
7 |
(8) |
|||||
| 3 |
875 |
(30) |
147 |
(35) |
195 |
(17) |
383 |
(41) |
108 |
(46) |
38 |
(31) |
4 |
(4) |
|||||
| Unknown |
218 |
(7) |
40 |
(9) |
23 |
(2) |
17 |
(2) |
21 |
(9) |
41 |
(33) |
76 |
(84) |
|||||
| LVI |
|||||||||||||||||||
| Positive |
519 |
(18) |
0 |
(0) |
77 |
(7) |
297 |
(32) |
114 |
(49) |
28 |
(23) |
3 |
(3) |
|||||
| Negative |
1747 |
(60) |
18 |
(4) |
994 |
(89) |
600 |
(64) |
85 |
(36) |
40 |
(33) |
10 |
(11) |
|||||
| Unknown |
661 |
(23) |
406 |
(96) |
47 |
(4) |
41 |
(4) |
34 |
(15) |
55 |
(45) |
78 |
(86) |
|||||
| No. of positive nodes |
|||||||||||||||||||
| 0 |
1439 |
(49) |
71 |
(17) |
1005 |
(90) |
339 |
(36) |
17 |
(7) |
7 |
(6) |
0 |
(0) |
|||||
| 1–3 |
497 |
(17) |
0 |
(0) |
0 |
(0) |
422 |
(45) |
65 |
(28) |
10 |
(8) |
0 |
(0) |
|||||
| ≥ 4 |
252 |
(9) |
0 |
(0) |
0 |
(0) |
124 |
(13) |
107 |
(46) |
20 |
(16) |
1 |
(1) |
|||||
| Positive, no. unknown |
3 |
(<1) |
0 |
(0) |
0 |
(0) |
0 |
(0) |
3 |
(1) |
0 |
(0) |
0 |
(0) |
|||||
| Nodal status unknown |
736 |
(25) |
353 |
(83) |
113 |
(10) |
53 |
(6) |
41 |
(18) |
86 |
(70) |
90 |
(99) |
|||||
| SMPBC attender |
|||||||||||||||||||
| Yes |
1574 |
(54) |
302 |
(71) |
704 |
(63) |
431 |
(46) |
81 |
(35) |
33 |
(27) |
23 |
(25) |
|||||
| No |
1353 |
(46) |
122 |
(29) |
414 |
(37) |
507 |
(54) |
152 |
(65) |
90 |
(73) |
68 |
(75) |
|||||
| Screen detected† |
|||||||||||||||||||
| Yes |
971 |
(62) |
238 |
(79) |
499 |
(71) |
189 |
(44) |
25 |
(31) |
11 |
(33) |
9 |
(39) |
|||||
| No | 603 | (38) | 64 | (21) | 205 | (29) | 242 | (56) | 56 | (69) | 22 | (67) | 14 | (61) | |||||
Note: ER = estrogen receptor, LVI = lymphovascular invasion, SMPBC = Screening Mammography Program of British Columbia. *Unless otherwise indicated. †Defined as diagnosis of breast cancer within 1 year after abnormal results on screening. For patients with synchronous bilateral disease, the first diagnosis was used to define the screen-detection variable, which was then assigned to both diagnoses.