Clinical Evaluation of Gastrointestinal Stromal Tumor of the Stomach

ABSTRACT

PURPOSE: Despite modern pathologic techniques, GISTs pose a dilemma in nomenclature, cellular origin, diagnosis, classification, and prognostication. The authors attempted to elucidate the clinical applications of known prognostic factors at our hospital on the basis of CD34 or CD117 positivity. METHODS: Immunostaining was done on 24 cases of GI tract tumor including leiomyoma, leiomyosarcoma, and GISTs treated in our hospital between 1991 and 2000. 20 cases that showed positive reactivity to either CD34 or CD117 were chosen, and a retrograde evaluation of the clinical characteristics and pathological characteristics was done. RESULTS: 16 of 24 cases (66.7%) showed a positive reactivity to CD34, 18 cases (75%) to CD117, and 20 cases (83.3%) to both CD34 and CD117. Complete resection was performed on all, with exception of one in which intraperitoneal metastasis was detected. The mean age of the patients was 58.9 (19~74) years, the mean tumor size was 8.1 cm (3~20) and there was no significant difference between the sexes. The overall survival rate was 80%. The difference of cumulative survival rate was significant when tumor size was 10 cm or greater (p=0.0021), mitotic count was 5/50 HPF or over (p<0.0001), or severe cellularity (p=0.0001), invasion (p<0.0001), necrosis (p=0.0185) or atypism (p<0.0001) were accompanied. CONCLUSION: Authors defined GIST as those case that were immunohistochemically positive to either CD34 or CD117. The prognostic factors those affected 5-year survival rate were tumor size, mitotic count, intratumoral necrosis, severecellularity, atypism and invasion. Additionally, the surgical treatment for this condition should be a complete resection of macroscopically identified tumor with adequate margin secured. Finally, a long term follow-up for the recurrence should be carried out.