A gist of gastrointestinal stromal tumors: A review

Table 1 Response Evaluation Criteria in Solid Tumors

Complete response	Disappearance of all target lesions
Partial response	At least a 30% decrease in the sum of the longest diameter of target lesions, taking as reference the baseline sum longest diameter
Progressive disease	At least a 20% increase in the sum of the longest diameter of target lesions, taking as reference the smallest sum longest diameter recorded since the treatment started or the appearance of one or more new lesions
Stable disease	Neither sufficient shrinkage to qualify for partial response nor sufficient increase to qualify for progressive disease, taking as reference the smallest sum longest diameter since the treatment started

Originated from [23], with permission.

Table 2 European Organization for Research and Treatment of Cancer metabolic response criteria for tumors evaluated with positron emission tomography

Complete metabolic response	Complete resolution of [18F]-FDG uptake within the tumor volume indistinguishable from surrounding normal tissue
Partial metabolic response	Reduction of a minimum of 15%-25% in tumor [18F]-FDG SUV after one cycle of chemotherapy Reduction of a minimum of > 25% in tumor [18F]-FDG SUV after more than one treatment cycle
Progressive metabolic disease	Increase in [18F]-FDG tumor SUV > 25% within the tumor region, visible increase in the extent of [18F]-FDG tumor uptake (> 20% in the longest dimension) Appearance of new [18F]-FDG uptake.
Stable metabolic disease	Increase in tumor [18F]-FDG SUV < 25%, decrease of < 15%. No visible increase in extent of [18F]-FDG tumor uptake (< 20% in the longest dimension)

Originated from [26], with permission. PET: Positron emission tomography; [¹⁸F]-FDG:

¹⁸F-fluoro-de-oxyglucose; SUV: Standardized uptake value.

Table 3 Risk stratification of gastrointestinal stromal tumors

Mitotic rate	Tumor size (cm)	Stomach	Jejunum/Ileum	Duodenum	Rectum
≤ 5/50 HPF	≤ 2	None	None	None	None
	> 2, ≤ 5	Very low	Low	Low	Low
	> 5, ≤ 10	Low	Moderate	High	High
	> 10	Moderate	High
> 5/50 HPF	≤ 2	None	High	NA	High
	> 2, ≤ 5	Moderate	High	High	High
	> 5, ≤ 10	High	High	High	High
	> 10	High	High

Originated from [54], with permission. HPF: High-power fields; NA: Not available.