Table 1.
Baseline characteristics of the two retrospective series of GIST
| Characteristics | First series of resected primary GIST | Second series of metastatic or locally advanced at diagnosis GIST |
|---|---|---|
| N | 87 | 22 |
| Male | 42 | 13 |
| Female | 45 | 9 |
| Age (years) | 65 (22–84) | 64 (39–79) |
| Median size (mm) | 58 (17–400) | 90 (45–240) |
| Location | ||
| Stomach | 52 (60 %) | 8 (36 %) |
| Small bowel | 24 (28 %) | 11 (50 %) |
| Other locations | 11 (12 %) | 3 (14 %) |
| Mitotic index per 50 HPF | ||
| ≤ 5 | 51 (59 %)a | 5 (26 %)a |
| 6–10 | 12 (14 %)a | 4 (21 %)a |
| > 10 | 23 (27 %)a | 10 (52 %)a |
| Unknown | 1 | 3 |
| Mutation status | ||
| KIT ex 11 | 40 (54 %)a | 12 (75 %)a |
| KIT ex 9 | 5 (7 %)a | 3 (19 %)a |
| KIT ex 13 | 1 (1 %)a | 1 (6 %)a |
| KIT ex 17 | 2 (3 %)a | 0 |
| PDGFRA ex 18 | 11 (15 %)a | 0 |
| D842V | 9 | 0 |
| No mutation on KIT or PDGFRA hotspots | 15 (20 %)a | 0 |
| Unknown | 13 | 6 |
| Prevalence of the variant KITL541 | 15 (17 %) | 9 (41 %) |
aPercentages are determined on the evaluable cases
HPF high-power field