OBJECTIVETo explore the clinicopathological characteristics, efficacy, and prognostic factors for patients with rectal gastrointestinal stromal tumor(GIST).

METHODSClinicopathological and follow-up data of 61 patients with rectal GIST in our department from January 1990 to October 2012 were analyzed retrospectively and pathology specimens were reviewed. Kaplan-Meier method was used to calculate the survival. Univariate analysis and multivariate analysis were performed to investigate the influencing factors of prognosis with Log-rank test and Cox regression model.

RESULTSThere were 42 male and 19 female patients with a median age of 59 years old. Eighteen cases(29.5%) were confirmed preoperatively as GIST by biopsy and 46 cases were diagnosed as GIST by first pathological examination. Fifteen cases(24.6%) were revised as GIST after re-examination of specimes among whom 14 cases had been diagnosed as leiomyoma or sarcoma, and 1 as neurolemmoma. Tumor location was above peritoneal reflection in 12 cases(19.7%) and below peritoneal reflection in 49(80.3%). Fifty-two patients underwent surgery, including 21 extended resections(lymph nodes clearance and combined organs resection simultaneously) and 31 local resections(tumor rejection or partial resection of rectal wall). Eleven patients received preoperative imatinib(400 mg/d). Forty-one cases received imatinib therapy after operation or biopsy diagnosis, including 25 cases who received palliative treatment for postoperative recurrence. Median follow-up time was 55(6 to 391) months and follow-up longer than 2 years was carried out in 46 patients. Overall survival rates of 1-, 2-, 3- , 5-year were 98%, 95.6%, 86.0% and 73.7% respectively. There were no significant differences between local resection group(96.4%, 92%, 83.3% and 77.3%) and extended resection group (100%, 94.7%, 89.50% and 82.6%)(χ(2)=0.004, P=0.947). Univariate analysis showed that survival was only associated with recurrence and metastasis (χ(2)=4.292, P=0.038). Multivariate Cox analysis showed postoperative survival was not associated with any factors(all P>0.05). The 3-year survival rate of patients with postoperative recurrence or metastasis receiving imatinib therapy was better as compared to those who did not received imatinib(82.7% vs. 71.4%).

CONCLUSIONSRectal GIST are more common in the lower rectum. Surgery is the main treatment for rectal GIST. Local complete resection is the mainstay treatment. Extensive resection and lymph node clearance may not improve survival. Imatinib can improve the prognosis of patients with recurrence or metastasis.