Table 3.
Use of trastuzumab among breast cancer patients diagnosed between 1998–2007
| SEER Stage | HER2 positivea, (%) |
HER2 discordantb, (%) |
HER2 negative/equivocal/unknown, (%) |
|
|---|---|---|---|---|
| 1998–2004 | 2005–2007 | 2004–2007 | 1998–2007 | |
| In situ | 0/1c (0) | 0/0 (0) | 0/0 (0) | 2/537 (<1) |
| Localized | 4/220 (2) | 35/79 (44) | 1/31 (3) | 12/1815 (<1) |
| Regional | 20/123 (16) | 28/41 (68) | 0/23 (0) | 10/619 (1.6) |
| Distant metastasis | 11/22 (50) | 8/10 (80) | 1/2 (50) | 2/68 (3) |
| Total | 35/366 (9) | 71/130 (55) | 2/56 (4) | 26/3039 (0.8) |
a
Patients were defined as HER2 positive if they had a positive HER2 test result by either FISH or IHC or both, but not discordant HER2 results.
b
Patients were defined as HER2 discordant if the IHC test was positive and the FISH test was negative (n = 55) or the other way around (n = 1).
c
The ratio in each cell refers to the number of patients who received trastuzumab divided by the total number of patients in that cell.