THZ1 targeting CDK7 suppresses c-KIT transcriptional activity in gastrointestinal stromal tumours.

BACKGROUND: Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal tract and are characterized by activating mutations of c-KIT or PDGFRa receptor tyrosine kinases (RTKs). Despite the clinical success of tyrosine kinase inhibitors (TKIs), more than half of GIST patients develop resistance due to a second mutation. Cyclin-dependent kinase 7 (CDK7) is the catalytic subunit of CDK-activating kinase (CAK), and it plays an important role in the regulation of cell cycle transitions and gene transcription. THZ1, a CDK7 inhibitor, exhibits a dose-dependent inhibitory effect in various cancers. METHODS: Data from the public GEO database and tissue microarray were used to analyse the gene expression levels of CDKs in GISTs. The impact of CDK7 knockdown and the CDK7 inhibitor THZ1 on GIST progression was investigated in vitro using CCK-8, colony formation, and flow cytometry assays and in vivo using a xenograft mouse model. RNA sequencing was performed to investigate the mechanism of GIST cell viability impairment mediated by THZ1 treatment. RESULTS: Our study demonstrated that CDK7 is relatively overexpressed in high-risk GISTs and predicts a poor outcome. A low concentration of THZ1 exhibited a pronounced antineoplastic effect in GIST cells in vivo and in vitro. Moreover, THZ1 exerted synergistic anticancer effects with imatinib. THZ1 treatment resulted in transcriptional modulation by inhibiting the phosphorylation of Ser2, Ser5, and Ser7 within RNA polymerase II (RNAPII). c-KIT, an oncogene driver of GIST, was transcriptionally repressed by THZ1 treatment or CDK7 knockdown. Transcriptome sequencing analysis showed that OSR1 acts as a downstream target of CDK7 and regulates c-KIT expression. Taken together, our results highlight elevated CDK7 expression as a predictor of poor outcome in GIST and present the combination of CDK7 and RTK inhibitors as a potent therapeutic strategy to improve the efficacy of GIST treatment. Video abstract.

High intratumoral expression of eIF4A1 promotes epithelial-to-mesenchymal transition and predicts unfavorable prognosis in gastric cancer.

Gastric cancer is an important health problem, being the fifth most common cancer and the third leading cause of cancer-related death worldwide. Aberrant protein translation contributes to the oncogenesis and development of cancers, and upregulation of translation initiation factor eIF4A1 has been observed in several kinds of malignancies. However, the role of eIF4A1 in gastric cancer progression remains unclear. In this study, we found that the expression of eIF4A1, a component of translation initiation complex, was increased in gastric cancer. High expression of eIF4A1 was positively associated with poor tumor differentiation, late T stage, lymph node metastasis, advanced TNM stage, and poor prognosis in patients with gastric cancer. Overexpression of eIF4A1 promoted the migration and invasion of gastric cancer cells in vitro and enhanced tumor metastasis in nude mice model. Mechanism studies revealed that eIF4A1 induced epithelial-to-mesenchymal transition (EMT) of gastric cancer cells through driving the translation of SNAI1 mRNA. Together, these findings indicate that eIF4A1 promotes EMT and metastasis of gastric cancer and suggest that eIF4A1 is a potential target for the adjuvant therapy for gastric cancer patients.

Incorporation of NLR into NIH stratification system increases predictive accuracy for surgically resected gastrointestinal stromal tumors.

Previous studies have reported that preoperative neutrophil-to-lymphocyte (NLR) and platelet-to-lymphocyte ratios were prognostic for various types of cancers. The aim of this study was to investigate the predictive utilities of preoperative peripheral blood counts in patients with gastrointestinal stromal tumors (GISTs). We enrolled 510 consecutive, previously untreated patients who underwent surgery for primary, localized GISTs. The relationship between recurrence-free survival and outcome variables was assessed by univariate and multivariate analyses, while the clinicopathologic relevance of NLR was determined using the Chi-square test. A preoperative NLR ≥2 was associated with poor prognosis in patients undergoing surgeries for primary, localized GISTs. It was an independent predictor only in patients classified as National Institutes of Health high risk but not in the entire population. Preoperative NLR is a feasible and reproducible peripheral biomarker that helps identify patients for intensive adjuvant therapy and frequent surveillance.

PIK3C2A is a gene-specific target of microRNA-518a-5p in imatinib mesylate-resistant gastrointestinal stromal tumor.

Imatinib mesylate resistance occurs in some patients with gastrointestinal stromal tumors (GISTs) during the course of treatment. In this study, we investigated the relationship between microRNAs (miRNAs) and imatinib-resistant GISTs, and the effect of miR-518a-5p on PIK3C2A in imatinib-resistant GISTs. A total of 20 matched-pair GIST samples from imatinib-resistant patients were included in the study. Each of the paired tumor specimens were from the same patient who had surgical removal of GISTs preimatinib and postimatinib treatment. Seven pairs of tissues were resected for microarray analysis, and the remaining 13 pairs were utilized for miRNAs analysis. Target genes were selected based on bioinformatics from multiple biological databases. Luciferase reporter assays were used to confirm the binding of miR-518a-5p to PIK3C2A 3'UTR. GIST882R-NC, 882R-miR-518a-5p-OE, and 882R-miR-518a-5p-KD cell lines were constructed using lentiviral vectors. miR-518a-5p and PIK3C2A expression in 882R-NC, 882R-OE, and 882R-KD cells was assessed by real-time PCR and western blotting. A cell counting kit was used to detect the influence of miR-518a-5p to cell proliferation. TUNEL staining was applied to detect the influence of miR-518a-5p to cell apoptosis. Microarray analysis showed that miR-518a-5p was downregulated in imatinib-resistant GISTs, and the expression of miR-518a-5p was confirmed with good concordance between real-time PCR and miRNA microarray results. Luciferase reporter assays indicated that miR-518a-5p bound to the PIK3C2A 3'UTR. Compared with 882R-OE, PIK3C2A expression was significantly increased in 882R-KD cells. MiR-518a-5p reduced 882R proliferation and promoted 882R apoptosis. In conclusion, PIK3C2A is a gene-specific target of miR-518a-5p in imatinib mesylate-resistant GISTs. Low expression of miR-518a-5p is likely to upregulate PIK3C2A and affect the cellular response to the drug, causing resistance to imatinib in GISTs.

Role of Surgery in the Management of Liver Metastases From Gastrointestinal Stromal Tumors.

Background: The clinical benefit of hepatectomy in patients with liver metastases from gastrointestinal stromal tumors (GIST) has not been well defined in this era of tyrosine kinase inhibitor (TKI). Our study aims to demonstrate the survival advantage of adding hepatectomy in patients with GIST liver metastases. Methods: Information on patients with metastatic GIST treated or consulted between January 2006 and December 2018 was retrieved. Patients without extrahepatic metastases were included and classified into the surgical (S group) and non-surgical (NS group). Clinicopathological features were compared and their association with survival was assessed. Results: A total of 119 patients were included in this retrospective analysis, 62 in the S group and 59 in the NS group. Comparison of clinicopathological features showed that a markedly higher proportion of patients in the S group had ≤3 hepatic lesions (79.0% vs. 29.8%, p<0.001). After a median follow-up duration of 56 months, patients in the S group had significantly better progression-free survival (PFS) and marginally improved overall survival (OS) than those in the NS group (3y PFS:86.2% vs. 64.6%, p=0.002; 5y OS: 91.5% vs. 78.3%, p=0.083). After propensity score matching, multivariate analysis identified hepatectomy as the only significant prognostic factor for PFS while age, hepatectomy and max tumor diameter were significant predictor for OS. Conclusions: Addition of hepatectomy provided longer disease control in patients with metastatic GIST confined to the liver. Upfront hepatectomy followed by imatinib therapy is worthwhile trying in patients with single and easily removable lesions.

Loss of GNE Predicts Lymph Node Metastasis in Early Gastric Cancer.

Endoscopic surgery is increasingly utilized for the treatment of early gastric cancer (EGC) worldwide, whereas lymph node metastasis (LNM) remains a critical risk factor for the relapse of EGC after endoscopic surgery. Therefore, identifying potential predictive factors and understanding the molecular mechanisms are urgently needed for improving the outcome of EGC patients with LNM. UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) is the key enzyme in the process of biosynthesis of CMP-Neu5Ac from UDP-N-acetylglucosamine (UDP-GlcNAc), which acts as a substrate for several reactions in glycan metabolism. In this study, we found that GNE was down-regulated in EGC patients with LNM. GNE expression as well as localization, tumor size, intravascular tumor thrombi and Lauren's classification were further identified as independent predictive factors for LNM. Combining GNE expression with traditional risk factors, including tumor size and differentiation degrees, could generate a better model for predicting LNM in EGC patients. Overall, our study implies that low GNE expression is a potential predictor of LNM in EGC.

Familial gastrointestinal stromal tumors with KIT germline mutation in a Chinese family: A case report.

BACKGROUND: Familial gastrointestinal stromal tumors (GISTs) is a rare autosomal dominant disorder characterized by an array of clinical manifestations. Only 35 kindreds with germline KIT mutations and six with germline PDGFRA mutations have been reported so far. It is often characterized by a series of manifestations, such as multiple lesions and hyperpigmentation. However, the effect of imatinib treatment in these patients is still uncertain. CASE SUMMARY: Here, we report two patients (father and daughter) in a Chinese family (for the first time) with germline KIT mutation, and described their pathology, genetics and clinical manifestations. A 25-year-old Chinese woman went to hospital because of abdominal pain, and computed tomography showed multiple tumors in the small intestine. Small pigmented spots appeared on the skin within a few months after birth. Her father also had multiple pigmented spots and a history of multifocal GISTs. Multiple GISTs associated with diffuse interstitial Cajal cells (ICCs) hyperplasia were positive for CD117 and DOG-1. Gene sequencing revealed a germline mutation at codon 560 of exon 11 (p.V560G) of KIT gene in these two patients. Imatinib therapy showed the long-lasting disease stability after resection. Remarkably, the hypopigmentation of the skin could also be observed. Luckily germline KIT mutation has not been identified yet in the 3-year-old daughter of the female patient. CONCLUSION: Diagnosis of familial GISTs depends on combination of diffuse ICCs hyperplasia, germline KIT/PDGFRA mutation, hyperpigmentation and family history.

Immune Cell Infiltration and the Expression of PD-1 and PD-L1 in Primary PDGFRA-Mutant Gastrointestinal Stromal Tumors.

PURPOSE: To characterize the immune cell profile and expression of PD-1, PD-L1, and IDO in PDGFRA-mutant gastrointestinal stromal tumors (GISTs). METHODS: The clinicopathological data of PDGFRA-mutant GIST patients who received surgical resection in Zhongshan Hospital between January 2013 and August 2019 were reviewed retrospectively. The specimens of tissue chips were detected for immune cell infiltration and the expression of PD-1, PD-L1, and IDO by immunohistochemical staining. RESULTS: CD3+, CD8+, and CD68+ cells were the main infiltrating immune cells in the 42 patients included in this study. In addition, CD4+, CD56+, Foxp3+, and CD20+ cells were also observed. A higher CD8+ T cell count was associated with smaller tumor size and PDGFRA D842V mutation (P = 0.047, P = 0.005). A higher CD3+ and CD68+ cell count was associated with a higher mitotic index (P = 0.022, P = 0.006). CD4+ and CD20+ cell count was associated with tumor morphology (P = 0.002, P = 0.045). PD-1 expression was present in 37 (88%) samples. Eighteen samples were positive for PD-L1 expression, and it was higher in small vs. large tumors (P = 0.012) and epithelioid and mixed cell type vs. spindle cell type GISTs (P = 0.046). IDO expression was positive in all 42 patients. The number of CD4+ cells was significantly greater in the specimens with high IDO expression (P = 0.012). CONCLUSION: There were abundant infiltrating immune cells in PDGFRA-mutant GISTs. PD-L1 expression was negatively associated with tumor size. The immunotherapy targeting PD-1/PD-L1 checkpoint and IDO may be valuable.

Clinical and Prognostic Significance of Tumor-Infiltrating CD8+ T Cells and PD-L1 Expression in Primary Gastrointestinal Stromal Tumors.

PURPOSE: Immunotherapy for gastrointestinal stromal tumors (GISTs) remains a clinical challenge. The present study aimed to explore the clinical and prognostic significance of immune cell infiltration and PD-L1 expression in GISTs. METHODS: A total of 507 clinical tissue specimens of primary GISTs were collected for immunohistochemical analysis of immune cell infiltration and PD-L1 expression. Influencing factors of survival were evaluated by Kaplan-Meier analysis. Univariate and multivariate analyses were performed using the Cox regression model. RESULTS: There were significant differences in sex, tumor location, size, mitotic index, NIH risk grade, and cell morphology between different gene mutation types of GISTs. Immune cell infiltration in GISTs mainly involved macrophages and T cells. PD-1 was expressed in 48.5% of the tissue specimens, and PD-L1 expression was detected in 46.0% of the samples. PD-L1 expression was negatively correlated with the tumor size and mitotic index but positively correlated with the number of CD8+ T cells. There were significant differences in the number of CD8+ T cells between different gene mutation types. Wild type-mutant GISTs were enriched with CD8+ T cells as compared with KIT- and PDGFRA-mutant GISTs. The number of CD8+ T cells was higher in non-gastric GISTs. PD-L1 and CD8+ T cells were independent predictors for better relapse-free survival of GISTs. CONCLUSIONS: PD-L1 expression is a predictive biomarker for better prognosis of GISTs. Non-gastric GIST patients with wild-type mutations may be the beneficiaries of PD-1/PD-L1 inhibitors.

Gastrointestinal stromal tumors (GISTs) with remarkable cystic change: a specific subtype of GISTs with relatively indolent behaviors and favorable prognoses.

PURPOSE: Gastrointestinal stromal tumors (GISTs) are typically solid neoplasms with small cystic change detected occasionally but in rare instances may present predominantly as cystic lesions. The histopathologic features and prognoses of cystic GISTs (cGISTs) are poorly understood. METHODS: We herein reviewed 20 cGISTs resected or consulted in our institution from January 1, 2003 to December 31, 2014. RESULTS: Of the 20 patients included, the mean age was 61 years and the male-to-female ratio was 9:11. The original locations were the stomach (n = 10, 50%), the small intestine (n = 9, 45%) and the omentum (n = 1, 5%). Indistinct diagnosis or misdiagnosis was established in 15 cases based only on preoperative radiology. Grossly, the cystic component made up the bulk of masses and was filled by dark bloody fluid and necrotic debris in 18 cases. Microscopically, cyst wall was composed of neoplastic spindle (n = 14, 70%)/epithelioid cells (n = 6, 30%) and collagenous fiber, with necrotic debris and granulation tissue lining on the inner surface. cGISTs resembled their solid counterparts in terms of morphology and immunohistology but demonstrated fewer malignant parameters. c-kit or PDGFRα mutations were detected in eleven cases with the remaining being wild type for these two mutations. Although classified as intermediate or high (3 and 17, respectively) risk of recurrence according to modified National Institute of Health criterion, most patients with cGISTs experienced long-term recurrence-free survival without adjuvant imatinib. CONCLUSIONS: Cystic GISTs is a relatively indolent subset of GISTs with favorable prognoses and adjuvant imatinib should be a prudent consideration.

Clinicopathological Features and Prognosis of Small Gastric Gastrointestinal Stromal Tumors (GISTs).

BACKGROUND: The aim of the present study was to evaluate the safety of endoscopic surgery, the clinicopathological features, and prognoses of small gastric gastrointestinal stromal tumors (GISTs). METHODS: Small gastric GIST patients (diameter: 0.10-2.00 cm) resected endoscopically in Zhongshan Hospital were retrospectively identified and clinicopathological features and outcomes were collected. The relationship between clinicopathological characteristics and tumor recurrence was analyzed. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal tumor diameter for predicting malignant potential. RESULTS: All lesions were completely removed by endoscopy and En bloc resection was 98.5%. The most frequent location was the gastric fundus (60.3%) and the average diameter of all lesions was 1.20 cm (range: 0.10-2.00 cm). Mitoses were calculated as more than 5/50 HPF in 44 (6.8%) patients and nuclear atypia was moderate in 243 (37.5%) patients, severe in 1 (0.2%). Necrosis, mucosal infiltration, and vascular infiltration were detected in 8 (1.2%), 5 (0.7%), and 3 (0.5%) patients, respectively. Tumor size was positively correlated with mitotic index (P < 0.001) and nuclear atypia (P < 0.001). After a median follow-up of 54 months, four patients were confirmed local recurrence. ROC curve analysis identified 1.45 cm as the best cut-off value to predict malignant potential (95% CI: 0·694-0·774). Survival analysis showed that patients with tumor diameters larger than 1.45 cm were associated with more local recurrences after resection (P = 0.011). CONCLUSIONS: Endoscopic surgery is feasible and safe for small gastric GISTs, especially those in favorable locations. Small gastric GISTs bear a good prognosis as a whole but those with diameters larger than 1.45 cm should receive more intensive surveillance or undergo endoscopic surgery.

[Efficacy analysis of targeted therapy combined with surgery in the treatment of recurrent and metastatic gastrointestinal stromal tumor].

OBJECTIVE: To investigate the efficacy of targeted therapy combined with surgery in the treatment of recurrent and metastatic gastrointestinal stromal tumor(GIST). METHODS: Clinicopathological and followed-up data of 318 patients with recurrent and metastatic GIST admitted in Zhongshan Hospital between January 2000 and December 2015 were analyzed retrospectively. According to different treatment methods, the patients were divided into four groups: surgery group (operation alone, 44 cases), target therapy group (imatinib alone, 108 cases), target therapy combined with surgery group (imatinib plus operation, 139 cases), other therapy group (chemotherapy, Chinese medicine and others, 27 cases). The progression-free survival (PFS) and overall survival (OS) of four groups were compared. RESULTS: The baseline informations, such as age, gender, primary site, et al, were not significantly different (all P>0.05), but the recurrent and metastatic site was significantly different among 4 groups (P=0.000). The medial PFS of surgery group, target therapy group, target therapy combined with surgery was 16(95%CI: 4.9 to 27.0) months, 44 (95%CI: 30.9 to 57.1) months, 35 (95%CI: 26.5 to 43.5) months, respectively, and the latter 2 groups had significantly longer PFS than surgery group(P=0.000), while no significant difference was found between target therapy group and target combined with surgery group (P=0.251). The median OS of surgery group, target therapy group, target therapy combined with surgery, and other therapy group was 24 (95%CI: 9.0 to 39.0) months, 69(95%CI: 40.8 to 97.2) months, 92(95%CI: 78.0 to 106.0) months, 12(95%CI: 9.5 to 14.5) months. Target therapy group and target therapy combined with surgery group had significantly longer OS than surgery and other therapy groups (P=0.000), while the target therapy combined with surgery group had significantly longer OS than target therapy group(P=0.028). CONCLUSION: Target therapy combined with surgery can prolong the survival of recurrent and metastatic GIST patients.

Role of surgery in patients with focally progressive gastrointestinal stromal tumors resistant to imatinib.

The benefits of surgery for focally progressive gastrointestinal stromal tumor (GIST) during imatinib therapy are still in discussion. The aim of this study was to compare the outcomes of surgical resection of progressive lesions following tyrosine kinase inhibitor (TKI) therapy (S group) or TKI therapy alone (NS group) in GIST patients. We retrospectively investigated 57 patients with focally progressive GIST during imatinib therapy who were treated in Zhongshan hospital, Fudan University. Progression-free survival (PFS) and overall survival (OS) in the S group were significantly longer than those in the NS group. Among S group, the patients with R0 resection showed longer PFS than R2 resection; however, no difference was found between these two groups. Moreover, PFS and OS were not different in the NS-S group compared with S group. On multivariate analysis, surgery is an independent prognostic factor for longer PFS and OS. Our study supports the decision of treating GIST patients who were focally resistant to imatinib with surgery resection based on its benefit.

RACK1 overexpression is linked to acquired imatinib resistance in gastrointestinal stromal tumor.

Although treatment with imatinib, which inhibits KIT and PDGFR, controls advanced disease in about 80% of gastrointestinal stromal tumor (GIST) patients, resistance to imatinib often develops. RACK1 (Receptor for Activated C Kinase 1) is a ribosomal protein that contributes to tumor progression by affecting proliferation, apoptosis, angiogenesis, and migration. Here, we found that c-KIT binds to RACK1 and increases proteasome-mediated RACK1 degradation. Imatinib treatment inhibits c-KIT activity and prevents RACK1 degradation, and RACK1 is upregulated in imatinib-resistant GIST cells compared to non-resistant parental cells. Moreover, Erk and Akt signaling were reactivated by imatinib in resistant GIST cells. RACK1 functioned as a scaffold protein and mediated Erk and Akt reactivation after imatinib treatment, thereby promoting GIST cell survival even in the presence of imatinib. Combined inhibition of KIT and RACK1 inhibited growth in imatinib-resistant GIST cell lines and reduced tumor relapse in GIST xenografts. These findings provide new insight into the role of RACK1 in imatinib resistance in GIST.

[Comparative study of laparoscopic and open surgery for gastric gastrointestinal stromal tumors].

OBJECTIVE: To investigate the feasibility and short-term efficacy of laparoscopic resection of primary localized gastric gastrointestinal stromal tumors (GIST) by comparing with open surgery. METHODS: Clinicopathological data of 167 gastric GIST patients undergoing operation in Zhongshan Hospital from June 2008 to December 2013 were retrospectively analyzed, among whom 55 received laparoscopic surgery and 112 underwent open surgery for primary local gastric GIST. Efficacy of different size and different location of GIST was compared between laparoscopic and open groups. RESULTS: There was no conversion to open surgery in laparoscopy group. Compared with open surgery, laparoscopic resection for gastric GIST smaller than 5 cm or located at anterior wall, greater curvature, lesser curvature, was associated with similar operation time(P>0.05), but less blood loss, shorter post-hospital stay or flatus time(all P<0.05). The operative outcomes were similar between laparoscopic and open resection for gastric GIST bigger than or equal to 5 cm or located at posterior wall(all P>0.05), except the longer operation time in laparoscopy group(P<0.05). The incidence of postoperative complication did not differ between two groups. Laparoscopic group had 2 patients with gastroparesis and open group had 2 gastroparesis, 2 pulmonary infection, and 1 poor wound healing(all P>0.05), which all recovered after conservative treatment. During 7 to 84 months(median 35) of follow-up, no recurrence or hepatic metastasis was found in laparoscopy group, and 3 hepatic metastases in open group. There was no significant difference of recurrence-free survival between two groups(P>0.05). CONCLUSION: Laparoscopic resection for gastric GIST is safe and effective in selected patients, especially for those with tumors smaller than 5 cm, or located at anterior wall, greater curvature, lesser curvature, whose short-term outcomes are better than open resection.

[Clinicopathological features of small gastrointestinal stromal tumors].

OBJECTIVE: To investigate the clinicopathological features of small gastrointestinal stromal tumors(GISTs) and to evaluate the efficacy of endoscopic therapy for GISTs. METHODS: Clinicopathological and follow-up data of 418 patients with GISTs undergoing endoscopic therapy in the Zhongshan Hospital between January 2009 and July 2014 were analyzed retrospectively. All the cases were evaluated by the NIH risk classification and AIFP classification, and were grouped according to the tumor size and location. Nuclear atypia and mitotic count were used to evaluate the biological behavior of small GIST. Efficacy of endoscopic therapy was analyzed with follow-up data. RESULTS: Out of 418 patients, GISTs located in the esophagus was 14(3.3%), in the stomach 389(93.1%), in the duodenum 5(1.2%), in the rectum 10(2.4%). A total of 412(98.6%) patients were mainly spindle cells, and mitosis was not found in 320(76.5%) patients. In 389 small stomach GIST, 245(58.6%) were in fundic region. Cases were divided into four groups according to the size and the result revealed the bigger the size, the more the mitotic count. Nuclear atypia in the 1.5-1.9 cm group was significantly higher compared to other groups. Cases were divided into four groups according to the location and the result revealed the mitotic count was not associated to the location. While the nuclear atypia of stomach GIST was significantly higher than that of esophageal GIST and the nuclear atypia of rectum GIST was significantly higher than that of other positions. The median follow-up was 32(4-69) months. One case(gastric fundus GIST, >1.5 cm) presented local recurrence 23 months after operation and underwent endoscopic resection again. No recurrence or metastasis was found in other patients. CONCLUSIONS: Endoscopic resection technique is effective for small GISTs patients. The small GISTs with 0.4 cm diameter or less are often benign and should be followed up for long time. The small GISTs with 0.5 cm diameter or more possess the risk of malignancy, then surgical resection should be performed. Rectum small GISTs (except for 0.4 cm diameter or less) have worse biological behavior and should be removed.

[Clinicopathological analysis of 80 patients with duodenum gastrointestinal stromal tumors].

OBJECTIVE: To explore the clinicopathological characteristics, efficacy, and prognostic factors for patients with duodenum gastrointestinal stromal tumor(GIST). METHODS: Clinicopathological and follow-up data of 80 patients with duodenum GIST in the Zhongshan Hospital from January 2000 to December 2013 were analyzed retrospectively. RESULTS: There were 38 male and 42 female patients with a median age of 54 years. The major symptoms were upper alimentary tract hemorrhage and abdominal pain. Thirty-nine patients received local tumor excision, 18 patients underwent segmental duodenectomy, 23 patients were subjected to pancreaticoduodenectomy, all these operations were R0 resection. Thirty patients received imatinib treatment after operation, and 11 among them had metastasis relapse. Recurrence-free survival rates of 1-, 3-, and 5-years were 96.2%, 90.6%and 78.6% retrospectively. Overall survival rates of 1-, 3-, and 5-years were 100%, 98.3% and 96.1%. Multivariate Cox analysis showed tumor size >5 cm, mitotic count >5 mitosis/50 HPF and intermediate/high NIH risk classification were associated with an increased risk of recurrence. The significant difference was not detected between the limited resection group and pancreaticoduodenectomy group in OS and RFS. CONCLUSIONS: Surgery is still the main treatment for duodenum GIST. The surgical program is mainly determined by the location and size of tumor. Imatinib therapy should be used if necessary.