Gastrointestinal stromal tumor. A study of 158 cases: clinicopathological features and prognostic factors.
OBJECTIVE
To increase knowledge on the behavior of gastrointestinal stromal tumors (GISTs) and factors influencing therapy.


METHODS
The clinicomorphological features of 158 GISTs were analyzed. Survival analysis was performed on the whole series, as well as on a selected group of patients with high risk GIST who did not receive imatinib mesylate. The impact of imatinib mesylate on the prognosis was investigated.


RESULTS
Most of the GISTs had a benign behavior. The risk class was a powerful prognostic factor but was unable to predict the outcome in a single case; even patients in the high risk class not receiving imatinib mesylate had a low mortality rate. In this group, it was the mitotic activity that better correlated with prognosis, and a cut point of 10 mitoses per 50 high-power field can be fixed to discriminate cases with favorable or unfavorable outcome. Patients with GISTs presenting as aggressive disease received great benefit from imatinib mesylate therapy.


CONCLUSIONS
Mitotic activity is important in predicting the outcome of patients with high risk GIST who present at diagnosis without dissemination. This finding can have therapeutic implications.
Bearzi
Italo
I
Department of Pathology, School of Medicine, Polytechnic University of the Marche Region, Ancona, Italy. i.bearzi@univpm.it
Mandolesi
Alessandra
A
Arduini
Federica
F
Costagliola
Antonello
A
Ranaldi
Renzo
R
D000230:Adenocarcinoma / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001549:Benzamides; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D041981:Gastrointestinal Tract / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D008938:Mitosis; D009361:Neoplasm Invasiveness; D010879:Piperazines / Q000627:therapeutic use; D011379:Prognosis; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D011743:Pyrimidines / Q000627:therapeutic use; D017154:Stromal Cells / Q000378:metabolism / Q000473:pathology; D016019:Survival Analysis
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D019009:Proto-Oncogene Proteins c-kit