title: [Clinical characteristics and prognosis analysis of 119 cases with giant gastrointestinal stromal tumor].
abstract: OBJECTIVE
  To investigate the clinical characteristics, diagnosis and treatment as well as prognostic factors of the giant gastrointestinal stromal tumor (GIST).
  
  
  METHODS
  Clinical data of 235 patients with high risk GIST treated in the Union Hospital, Tongi Medical College, Huazhong University of Science and Technology between January 2005 and July 2015 were retrospectively analyzed. Patients were divided into giant GIST group (diameter equal to or larger than 10 cm, 119 cases) and high risk group (diameter less than 10 cm, 116 cases) according to tumor size. Clinical characteristics and prognosis of two groups were compared and the clinical features of giant GIST were summarized. Multivariate analysis was performed to evaluate the prognostic factors of giant GIST with Cox regression model.
  
  
  RESULTS
  Of the 119 patients with giant GIST, which accounted for 50.6%(119/235) of all the high risk patients, there were 63 male and 56 female patients with a median age of 53(20-82) years. Primary giant GIST of 43(36.1%) located in the stomach, of 39(32.8%) in the small intestine, 5(4.2%) in the colon and rectum, and of 32 (26.9%) outside the gastrointestinal tract (mesentery, retroperitoneum, abdominal cavity, etc) and pelvic. Compared to high risk group, age of onset was younger [ratio of ≤50 years, 44.5%(53/119) vs. 31.9%(37/116), P = 0.046] and incidence of outside the gastrointestinal tract was significantly higher [26.9%(32/119) vs. 9.5%(11/116), P=0.000] in giant GIST group. All the giant GIST patients underwent surgical resection, including 115 cases(96.6%) of R0 resection, 3 cases(2.5%) of R1 resection and 1 case(0.9%) of R2 resection, besides, 32 cases(26.9%) underwent expanded resection (namely, underwent lymphadenectomy or combined organ resection simultaneously). Thirty-nine giant GIST cases(32.8%)accepted imatinib 400 mg/d for targeted therapy after operations, which was not significantly different with high risk group (46 cases, 39.6%, P=0.232). Relapse and metastasis occurred in 8 cases in giant GIST group. The 1-, 3-, 5-year overall survival rates of giant GIST group were 94.5%, 89.3%, 79.4% respectively and of high risk group were 99.1%, 92.9%, 85.1% respectively, and no significant difference was found (P=0.788). The 1-, 3-, 5-year recurrence-free survival rates of giant GIST group were 93.6%, 85.1%, 72.8% respectively and of high risk group were 99.1%, 91.7%, 84.2% respectively, and no significant difference was found as well (P=0.932). Multivariate analysis revealed that gender (P=0.047, RR=0.383, 95%CI:0.149-0.987), mitotic count (P=0.001, RR=0.216, 95%CI:0.087-0.538) and targeted therapy(P=0.019, RR=5.719, 95%CI:1.324-24.695) were prognostic risk factors of overall survival (OS), moreover, tumor size (P=0.024, RR=0.368, 95%CI:0.155-0.875) and mitotic count(P=0.007, RR=0.357, 95%CI:0.169-0.755) were prognostic risk factors of RFS.
  
  
  CONCLUSIONS
  Giant GIST is not unusual in GIST and more likely occurs outside gastrointestinal tract. Complete surgical excision combined with targeted therapy can improve the prognosis significantly. The prognosis of giant GIST and common high risk GIST is similar. Mitotic count is the most important prognostic factor.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Xiangyu
authors.initials: X
authors.lastname: Zeng
authors.forename: Jinbo
authors.initials: J
authors.lastname: Gao
authors.forename: Weizhen
authors.initials: W
authors.lastname: Liu
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Shuai
authors.forename: Ke
authors.initials: K
authors.lastname: Liu
authors.forename: Xinghua
authors.initials: X
authors.lastname: Liu
authors.forename: Ming
authors.initials: M
authors.lastname: Cai
authors.forename: Kailin
authors.initials: K
authors.lastname: Cai
authors.forename: Guobin
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Gastrointestinal Surgery, Union Hospital, Tongi Medical College, Huazhong University of Science and Technology, Wuhan 430022, China. tao_kaixiong@163.com.
authors.forename: Kaixiong
authors.initials: K
authors.lastname: Tao
mesh_terms: D034841:Abdominal Cavity; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy / Q000473:pathology*; D006801:Humans; D000068877:Imatinib Mesylate / Q000627:therapeutic use*; D007421:Intestine, Small; D008197:Lymph Node Excision; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D000068877:Imatinib Mesylate