Gastrointestinal stromal tumor: 15-years' experience in a single center.
BACKGROUND
Gastrointestinal stromal tumor (GIST) is known for its wide variability in biological behaviors and it is difficult to predict its malignant potential. The aim of this study is to explore the characteristics and prognostic factors of GIST.


METHODS
Clinical and pathological data of 497 GIST patients in our center between 1997 and 2012 were reviewed.


RESULTS
Patients were categorized into very low-, low-, intermediate- and high-risk groups according to modified National Institutes of Health (NIH) consensus classification system. Among the 401 patients untreated with imatinib mesylate (IM), 5-year overall survival (OS) in very low-, low-, intermediate- and high-risk groups was 100%, 100%, 89.6% and 65.9%; and 5-year relapse-free survival (RFS) was 100%, 98.1%, 90.9% and 44.5%, respectively. Univariate analysis revealed that sex, tumor size, mitotic rate, risk grade, CD34 expression, and adjacent involvement were predictors of OS or RFS. COX hazard proportional model (Forward LR) showed that large tumor size, high mitotic rate, and high risk grade were independent risk factors to OS, whereas high mitotic rate, high risk grade and adjacent organ involvement were independent risk factors to RFS. The intermediate-high risk patients who received IM adjuvant therapy (n = 87) had better 5-year OS and RFS than those who did not (n = 188) (94.9% vs. 72.1; 82.3% vs. 56.3%, respectively). Similarly, advanced GIST patients underwent IM therapy (n = 45) had better 3-year OS and 1-year progression-free survival (PFS) than those who didn't (n = 42) (75.6% vs. 6.8%; 87.6% vs. 12.4%, respectively).


CONCLUSIONS
Very low- and low-risk GISTs can be treated with surgery alone. Large tumor size, high mitotic rate, high risk grade, and adjacent organ involvement contribute to the poor outcome. IM therapy significantly improves the survival of intermediate-high risk or advanced GIST patients.
Ming
M
Wang
Jia
J
Xu
Yun
Y
Zhang
Lin
L
Tu
Wei-Qing
WQ
Qiu
Chao-Jie
CJ
Wang
Yan-Ying
YY
Shen
Qiang
Q
Liu
Department of General Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Floor 11, Building 7, NO, 1630, Dongfang Road, Shanghai 200127, China. caohuishcn@hotmail.com.
Hui
H
Cao
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001549:Benzamides / Q000627:therapeutic use; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D046152:Gastrointestinal Stromal Tumors / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D006801:Humans; D000068877:Imatinib Mesylate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D008940:Mitotic Index; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D010879:Piperazines / Q000627:therapeutic use; D016016:Proportional Hazards Models; D011743:Pyrimidines / Q000627:therapeutic use; D012307:Risk Factors; D047368:Tumor Burden; D055815:Young Adult
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate