Table 3 Distribution of different DCIS grades by screening status and age group
| Â | Â | Detected at mass screening | Screen negative | P value | ||
|---|---|---|---|---|---|---|
| Â | Â | N | % | N | % | Â |
Age group | Â | Â | Â | Â | Â | Â |
<49 | Â | 0 | Â | 0 | Â | Â |
| Â | Low-grade DCIS | 0 | n.a. | 0 | n.a. | Â |
| Â | Intermediate-grade DCIS | 0 | n.a. | 0 | n.a. | Â |
| Â | High-grade DCIS | 0 | n.a. | 0 | n.a. | Â |
49–75 |  | 1429 |  | 261 |  |  |
| Â | Low-grade DCIS | 234 | 16.4Â % | 49 | 18.8Â % | Â |
| Â | Intermediate-grade DCIS | 452 | 31.6Â % | 71 | 27.2Â % | 0.579 |
| Â | High-grade DCIS | 743 | 52.0Â % | 141 | 54.0Â % | Â |
>75 | Â | 1 | Â | 2 | Â | Â |
| Â | Low-grade DCIS | 0 | 0.0Â % | 0 | 0.0Â % | Â |
| Â | Intermediate-grade DCIS | 0 | 0.0Â % | 2 | 100.0Â % | 0.297 |
| Â | High-grade DCIS | 1 | 100.0Â % | 0 | 0.0Â % | Â |