Table 1B.
Classification with GIST location proposed by Miettinen and Lasota in 200624
| Risk roup | Maximal tumor diameter | Mitotic count/50 hpf a | Estimated rate of relapse according to GIST location | |||
|---|---|---|---|---|---|---|
|
| ||||||
| Gastric | Jejuno ileal | Duodenal | Rectal | |||
| 1 | ≤2 cm | ≤5 | 0 | 0 | 0 | 0 |
| 2 | >2–≤5 cm | ≤5 | 1.9% | 4.3% | 8.3% | 8.5% |
| 3a | >5–≤10 cm | ≤5 | 3.6% | 24% | –b | –b |
| 3b | >10 cm | ≤5 | 12% | 52% | 34% | 57% |
| 4 | ≤2 cm | >5 | 0 | 50% | – | 54% |
| 5 | >2–≤5 cm | >5 | 16% | 73% | 50% | 52% |
| 6a | >5–≤10 cm | >5 | 55% | 85% | –b | –b |
Notes:
a
The mitotic count was made in a 5 mm2 surface, which corresponds to 20–25 fields at ×400 magnification with recent microscopes;
b
Subgroups with insufficient number of patients to estimate the rate of relapse risk.
Abbreviations: GIST, gastrointestinal stromal tumors; hpf, high-power fields.