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.

Benzamides ; Female ; Gastrointestinal Stromal Tumors ; therapy ; Humans ; Imatinib Mesylate ; Male ; Neoplasm Recurrence, Local ; Piperazines ; Prognosis ; Pyrimidines ; Rectal Neoplasms ; pathology ; therapy ; Retrospective Studies ; Survival Rate

Objective To explore the value of KRAS mutation predicting prognosis of patients with colorectal liver-only metastasis after hepatectomy.Methods The retrospective case-control study was conducted.The clinicopathological data of 79 patients with colorectal liver-only metastasis who underwent hepatectomy in the Sun Yat-sen University Cancer Center between October 2010 and October 2016 were collected.KRAS mutation in colorectal cancer tissue was detected by fluorescent quantitative polymerase chain reaction (PCR) and laser flight mass spectrometer.Observation indicators:(1) KRAS mutation;(2) relationship between KRAS mutation and clinicopathological factors of patients with colorectal liver-only metastasis;(3) follow-up and survival situations.Follow-up using outpatient examination and telephone interview was performed to detect recurrence-free survival and overall survival up to June 30,2017.The relationship between KRAS mutation and clinicopathological factors of patients with colorectal liver-only metastasis was analyzed by the chi-square test or Fisher exact probability.The survival curve and time were respectively drawn and calculated by the Kaplan-Meier method,and COX regression model was used for survival analysis.Results (1) KRAS mutation:79 patients received KRAS gene detection of surgical tumor tissues,including 54 in wide-type mutation and 25 in mutant-type mutation.Of 25 patients in mutant-type mutation,mutation at codon 12 of KRAS exon 2 was in 21 patients,and GGT＞GAT (G12D),GGT＞GTT (G12V),GGT＞TGT (G12C),GGT＞GCT (G12A) and GGT＞CGT (G12R) of mutation types were respectively detected in 13,4,2,1 and 1 patients;mutation at codon 13 of KRAS exon 2 was in 3 patients,with a mutation type of GGC＞GAC (G13D);mutation at codon 61 of KRAS exon 3 was in 1 patient,with a mutation type of CAA＞CAT (Q61H).(2) Relationship between KRAS mutation and clinicopathological factors of patients with colorectal liver-only metastasis:primary tumor located in right and left hemicolon were detected in 11,14 patients with mutant-type mutation and 7,47 patients with wide-type mutation,respectively,with a statistically significant difference (x2=9.357,P＜0.05).(3) Follow-up and survival situations:79 patients were followed up for 2.0-71.0 months,with a median time of 29.0 months.Median recurrence-free survival time and median overall survival time were respectively 11.3 months,43.5 months in patients with mutant-type mutation and 9.9 months,44.3 months in patients with wide-type mutation,respectively,with no statistically significant difference in recurrence-free and overall survivals [hazard ratio (HR)=1.255,1.108,95％ confidence interval (CI):0.741-2.126,0.521-2.355,P＞0.05].Further analysis:of patients with low clinical risk score (CRS) of Memorial Sloan Caitlin Cancer Center (MSKCC),median recurrence-free survival time was 11.3 months in 17 patients with mutant-type mutation and 23.5 months in 26 patients with wide-type mutation,with a statistically significant difference in recurrence-free survival of patients (HR=2.082,95％CI:1.006-4.307,P＜0.05).The median overall survival time was 44.6 months in 17 patients with mutant-type mutation and 49.0 months in 26 patients with wide-type mutation,with no statistically significant difference in overall survival of patients (HR =1.165,95％CI:0.413-3.282,P＞0.05).Of patients with high CRS of MSKCC,median recurrence-free survival time and median overall survival time were respectively 5.6 months,28.7 months in 7 patients with mutant-type mutation and 4.5 months,36.7 months in 24 patients with wide-type mutation,with no statistically significant difference in recurrence-free and overall survivals (HR=0.402,1.197,95％CI:0.284-1.656,0.371-3.866,P＞0.05).Conclusions KRAS mutation is often detected in patients with right colon cancer.Recurrence-free survival time is obviously reduced in patients with KRAS mutation and low CRS of MSKCC.