Table 2.
Percentage change following the allocation of the unknown ER and HER2 breast cancer cases to non-missing categories among patients diagnosed in Ireland, 2004–2013.
| Total (n=24,845) | |||||
|---|---|---|---|---|---|
| Before correction | After correction | ||||
| n | % | n | % | % change | |
| ER status | |||||
| Positive | 19,264 | 77.5 | 20,419 | 82.2 | 6.0 |
| Negative | 4,161 | 16.7 | 4426 | 17.8 | 6.4 |
| Unknown | 1,420 | 5.7 | – | – | – |
| ER/HER2 status | |||||
| ER+/HER2− | 14,782 | 59.5 | 17,502 | 70.4 | 18.4 |
| ER+/HER2+ | 2,390 | 9.6 | 2,892 | 11.6 | 21.0 |
| ER−/HER2+ | 1,439 | 5.8 | 1,707 | 6.9 | 18.6 |
| ER−/HER2− | 2,353 | 9.5 | 2,741 | 11.1 | 16.5 |
| Unknown | 3,881 | 15.6 | – | – | – |
*
Allocation of ER-unknow cases to either ER+ or ER− categories according to the observed distributions of ER+ and ER− breast cancer cases, conditional on age at diagnosis and year of diagnosis [6]