Table 1.
Modified NIH classification system proposed by Joensuu [23]
| Risk category | Tumor size (cm) | Mitotic index (/50 HPFs) | Primary tumor site |
|---|---|---|---|
| Very low risk | ≤ 2.0 | ≤ 5 | Any |
| Low risk | 2.1-5.0 | ≤ 5 | Any |
| Intermediate risk | ≤ 5.0 | 6-10 | Gastric |
| 5.1-10.0 | ≤ 5 | Gastric | |
| High risk | Any | Any | Tumor rupture |
| > 10.0 | Any | Any | |
| Any | > 10 | Any | |
| > 5.0 | > 5 | Any | |
| ≤ 5.0 | > 5 | Non-gastric | |
| 5.1-10.0 | ≤ 5 | Non-gastric |
Adopted from Joensuu H. Hum Pathol. 2008;39:1411-9, with permission of Elsevier [23]. NIH, National Institutes of Health; HPFs, high-power fields.