|
Comments (GIST)
|   |
|
Comments (GIST)
| |
* The required total count of mitoses is per 5 mm2 on the glass slide section. With the use of older model microscopes, 50 HPF is equivalent to 5 mm2. Most modern microscopes with wider 40X lenses/fields require approximately 20 to 25 HPF to encompass 5 mm2. If necessary, please measure field of view to accurately determine actual number of fields required to be counted on individual microscopes to encompass 5 mm2.
Table 1. Guidelines for Risk Assessment of Primary Gastrointestinal Stromal Tumor (GIST)
|
Tumor Parameters |
Risk of Progressive Disease# (%) |
||||
|
Mitotic Rate |
Size |
Gastric |
Duodenum |
Jejunum/Ileum |
Rectum |
|
≤5 per 5 mm2 |
≤2 cm |
None (0%) |
None (0%) |
None (0%) |
None (0%) |
|
>2 - ≤5 cm |
Very low (1.9%) |
Low (8.3%) |
Low (4.3%) |
Low (8.5%) |
|
|
>5 - ≤10 cm |
Low (3.6%) |
(Insufficient data) |
Moderate (24%) |
(Insufficient data) |
|
|
>10 cm |
Moderate (10%) |
High (34%) |
High (52%) |
High (57%) |
|
|
>5 per 5 mm2 |
≤2 cm |
None## |
(Insufficient data) |
High## |
High (54%) |
|
>2 - ≤5 cm |
Moderate (16%) |
High (50%) |
High (73%) |
High (52%) |
|
|
>5 - ≤10 cm |
High (55%) |
(Insufficient data) |
High (85%) |
(Insufficient data) |
|
|
>10 cm |
High (86%) |
High (86%) |
High (90%) |
High (71%) |
|
*For microscopes with a 0.5 mm field diameter, approximately 25 fields should be examined to evaluate a 5 mm2 area.