Surgical treatment and prognostic analysis for gastrointestinal stromal tumors (GISTs) of the small intestine: before the era of imatinib mesylate

Molecular characteristics and immune microenvironment of gastrointestinal stromal tumours: targets for therapeutic strategies

Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours, arising mainly from the interstitial cells of Cajal (ICCs) of the gastrointestinal tract. As radiotherapy and chemotherapy are generally ineffective for GISTs, the current primary treatment is surgical resection. However, surgical resection is not choice for most patients. Therefore, new therapeutic strategies are urgently needed. Targeted therapy, represented by tyrosine kinase inhibitors (TKIs), and immunotherapy, represented by immune checkpoint inhibitor therapies and chimeric antigen receptor T-cell immunotherapy (CAR-T), offer new therapeutic options in GISTs and have shown promising treatment responses. In this review, we summarize the molecular classification and immune microenvironment of GISTs and discuss the corresponding targeted therapy and immunotherapy options. This updated knowledge may provide more options for future therapeutic strategies and applications in GISTs.

Neoadjuvant Imatinib in Gastrointestinal Stromal Tumors (GIST): The First Analysis of a Mexican Population

Introduction Gastrointestinal stromal tumors (GISTs) are neoplasms originating from the interstitial cells of Cajal, pacemaker cells responsible for intestinal motility. Patients with locally advanced GISTs and those with borderline resections due to the proximity of vital anatomical structures, which could result in unacceptable post-surgical morbidity, require special therapeutic consideration. Imatinib, a tyrosine kinase inhibitor, has demonstrated significant success in the non-surgical management of metastatic GIST, and its favorable impact on overall survival in the adjuvant setting makes it logical to speculate on the benefit it could provide as a neoadjuvant medication in patients with locally advanced disease. Methods Patients aged 18-90 years with a diagnosis of GIST confirmed by immunohistochemistry (CD117 positivity) who were treated at the Oncology Hospital of Centro Médico Nacional Siglo XXI in Mexico City from January 2012 to December 2016 were included in the study. It is a retrospective study with a duration of four years. Clinical data were collected from the medical records, which included sex, age, tumor location, initial resectability, reason for unresectability, initial tumor size, and mitotic rate. In the case of unresectable disease, patients who were evaluated by medical oncology and who had received treatment with 400 mg of imatinib daily were evaluated. Results A total of 312 patients diagnosed with GIST were analyzed. One hundred thirty-one were men (42%) with a mean age of 57 years, and 181 were women (58%) with a mean age of 59 years. The most frequent anatomical location was the stomach (n=185, 59.2%). At the time of diagnosis, 210 patients (67.3%) presented with resectable disease, while n=102 patients (32.7%) had unresectable disease. A total of 102 patients with unresectable disease received therapy with 400 mg of imatinib per day. Sixteen patients (15.7%) presented a reduction in tumor dimensions and underwent surgery. Conclusion The study highlights the importance of complete surgical resection and the potential benefit of neoadjuvant imatinib therapy in converting unresectable to resectable disease. The results suggest that imatinib can be effective in converting unresectable GISTs to resectable ones, allowing for a complete resection to be performed and obtaining an R0 resection in 93.7% of these cases.

Clinicopathological Characteristics and the First Mutational Analysis of Gastrointestinal Stromal Tumors From Mexico: A Single Institution Experience

Background Gastrointestinal stromal tumors (GISTs) arise from Cajal's interstitial cell precursors and display a variety of genetic mutations, primarily in the KIT and PDGFRA genes. These mutations are linked to tumor location, prognosis, and response to treatment. This study delves into the mutational patterns of GISTs in a Mexican population and their impact on overall survival (OS) and disease-free survival (DFS). Methodology This retrospective study examined 42 GIST cases diagnosed at the Oncology Hospital of the National Medical Center XXI Century between January 2018 and December 2020. Clinical, histological, and immunohistochemical data were gathered, and mutational analysis of KIT and PDGFRA genes was conducted using second-generation sequencing. Results The study group consisted of 52.4% females and 47.6% males, with an average age of 62.6 years. The most common tumor site was the stomach (59.5%), followed by the small intestine (26.2%). KIT mutations were detected in 71.4% of cases, predominantly involving exon 11. PDGFRA mutations were observed in 7.1% of cases. Recurrence was noted in 9.5% of patients, all with high-risk tumors. No significant link was identified between specific mutations and OS or DFS. Conclusions This investigation sheds light on the genetic landscape of GISTs in the Mexican population. While no significant association was established between particular mutations and survival outcomes, the study emphasizes the importance of molecular profiling in treatment decision-making. Further studies with larger sample sizes and longer follow-up periods are necessary to validate these results and explore their clinical relevance.

Feasibility and efficacy of minimally invasive limited resection for primary duodenal gastrointestinal stromal tumors: a retrospective cohort study

BACKGROUND

The primary duodenal gastrointestinal stromal tumor (GIST) is a rare type of gastrointestinal tract tumor. Limited resection (LR) has been increasingly performed for duodenal GIST. However, only a few studies reported minimally invasive limited resection (MI-LR) for primary duodenal GIST.

METHODS

The clinical data of 33 patients with primary duodenal GIST from December 2014 to February 2024 were retrospectively analyzed including 23 who received MI-LR and 10 who received laparoscopic or robotic pancreaticoduodenectomy (LPD/RPD).

RESULTS

A total of 33 patients with primary duodenal GIST were enrolled and retrospectively reviewed. Patients received MI-LR exhibited less OT (280 vs. 388.5min, P=0.004), EBL (100 vs. 450ml, P<0.001), and lower morbidity of postoperative complications (52.2% vs. 100%, P=0.013) than LPD/RPD. Patients received LPD/RPD burdened more aggressive tumors with larger size (P=0.047), higher classification (P<0.001), and more mitotic count/50 HPF(P=0.005) compared with patients received MI-LR. The oncological outcomes were similar in MI-LR group and LPD/RPD group. All the patients underwent MI-LR with no conversion, including 12 cases of LLR and 11 cases of RLR. All of the clinicopathological data of the patients were similar in both groups. The median OT was 280(210-480) min and 257(180-450) min, and the median EBL was 100(20-1000) mL and 100(20-200) mL in the LLR and the RLR group separately. The postoperative complications mainly included DGE (LLR 4 cases, 33.4% and RLR 4 cases, 36.4%), intestinal fistula (LLR 2 cases, 16.7%, and RLR 0 case), gastrointestinal hemorrhage (LLR 0 case and RLR 1 case, 9.1%), and intra-abdominal infection (LLR 3 cases, 25.0% and RLR 1 case, 9.1%). The median postoperative length of hospitalization was 19.5(7-46) days in the LLR group and 19(9-38) days in the RLR group. No anastomotic stenosis, local recurrence or distant metastasis was observed during the follow-up period in the two groups.

CONCLUSIONS

Minimally invasive limited resection is an optional treatment for primary duodenal GIST with satisfactory short-term and long-term oncological outcomes.

Gastrointestinal stromal tumors of the small intestine: the challenge of diagnosis and the outcome of management

PURPOSES

Gastrointestinal stromal tumor (GIST) is a rare small intestinal tumor. Most patients usually report long-period complaints due to difficult diagnoses. A high grade of suspicion is required for early diagnosis and initiation of the proper management.

METHODS

A retrospective study of all patients with small intestinal GIST who were operated in the period between January 2008 and May 2021 at Mansoura University Gastrointestinal Surgical Center (GIST).

RESULTS

Thirty-four patients were included in the study with a mean age of 58.15 years (± 12.65) with a male to female ratio of 1.3:1. The mean duration between onset of symptoms and diagnosis was 4.62 years (± 2.34). Diagnosis of a small intestinal lesion was accomplished through abdominal computed tomography (CT) in 19 patients (55.9%). The mean size of the tumor was 8.76 cm (± 7.76) ranging from 1.5 to 35 cm. The lesion was of ileal origin in 20 cases (58.8%) and jejunal in 14 cases (41.2%). During the scheduled follow-up period, tumor recurrence occurred in one patient (2.9%). No mortality was encountered.

CONCLUSION

Diagnosis of a small bowel GISTs requires a high grade of suspicion. Implementing new diagnostic techniques like angiography, capsule endoscopy, and enteroscopy should be encouraged when suspecting these lesions. Surgical resection is always associated with an excellent postoperative recovery profile and very low recurrence rates.

Diagnostic and Therapeutic Challenges in the Management of Acute Massive Overt Bleeding of Jejunal Gastrointestinal Stromal Tumours: Case Series

INTRODUCTION

Jejunal gastrointestinal stromal tumours (GIST) are rare mesenchymal tumours. Acute massive overt bleeding from jejunal GIST is very rare and poses both diagnostic and therapeutic challenges in emergent conditions.

METHODS

A case series with retrospective analysis of prospectively maintained database of patients presenting with acute massive overt bleeding secondary to histologically proven jejunal GIST was done. Clinical characteristics, endoscopic and imaging diagnostic features, histological findings, surgical procedures and outcomes in these patients were studied.

RESULTS

Three patients were included in this case series. Mean age of presentation was 49.0 years with two male and one female patient. All three patients presented with melena and hemodynamic instability, resuscitated with adequate blood transfusions. Routine endoscopic assessment were inconclusive. Multiphasic Computed Tomographic Angiography (CTA) revealed hypodense hypervascular mass in jejunum in all three patients. One patient was unresponsive to blood transfusion and underwent emergency exploratory laparotomy. One patient underwent laparoscopic resection and reconstruction. Mean length of hospital stay was 5.3 days. Histopathological examination confirmed jejunal GIST in all three patients with microscopically negative resection margins. Two patients were disease free till 18-month follow-up and the one patient lost to follow-up after 1 year.

CONCLUSION

Multiphasic CTA is a single-step diagnostic tool for localisation of bleed and assessment of tumour characteristics in emergent conditions. Surgical resection is the mainstay of treatment for both control of bleed and to provide oncologically clear resection margins.

Association between R1 resection and oncological outcome in resectable gastrointestinal stromal tumors without tumor rupture: A systematic review and meta-analysis

BACKGROUND

The influence of positive microscopic margin (R1) resection on the prognosis of gastrointestinal stromal tumors (GISTs) is controversial. Tumor rupture is significantly associated with the occurrence of R1 resection and may be a confounder of R1 resection in GISTs. The present meta-analysis evaluated the real influence of R1 resection on the prognosis of GISTs by excluding the confounding effect of tumor rupture.

METHODS

The PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov databases were searched. Studies that compared R1 with negative microscopic margin (R0) resection in GIST patients and reported the time-to-event data of recurrence-free survival (RFS) or disease-free survival (DFS) were eligible for inclusion. The quality of the observational studies was assessed using the Newcastle-Ottawa scale.

RESULTS

Of the 4896 records screened, 23 retrospective studies with 6248 participants were selected. In the overall analysis, R1 resection resulted in a significantly shorter RFS/DFS than R0 resection for GISTs (HR = 1.80, 95% CI = 1.54-2.10, P < 0.001, I² = 14%). However, the inferior RFS/DFS vanished when tumor rupture cases were excluded (HR = 1.34, 95% CI = 0.98-1.83, P = 0.07, I² = 33%). Sensitivity analysis by high-quality studies brought about a more robust HR of 1.15 (95% CI = 0.88-1.50, P = 0.29), with low heterogeneity (I² = 0%). The qualities of evidence for the outcomes were high.

CONCLUSIONS

This meta-analysis shows that R1 resection did not influence the survival outcome of GISTs. Reresection may not be necessary when positive microscopic margins exist. This analysis could provide high-quality evidence for the development of guidelines.

Characteristics and prognosis of jejunoileal gastrointestinal stromal tumours (GISTs) in the era of imatinib: a comparative study with gastric GISTs

BACKGROUND

Gastrointestinal stromal tumours (GISTs) located in the jejunum or ileum (JI-GIST) are considered worse prognosis compared to those of gastric (G-GIST) location. It has been suggested that this dogma should be revised. The aim of this study was to describe the characteristics of jejunoileal GISTs and its prognosis and to compare them with G-GISTs in the era of imatinib.

METHODS

We retrospectively reviewed the clinical histories of all the patients diagnosed with GISTs between January 2000 and November 2016: Clinical and pathological data, as recurrence, metastatic state, disease-free survival (DFS) as well as overall survival (OS) rates of patients were reviewed.

RESULTS

JI-GIST patients comprise 29 cases (37.7%). Compared to G-GIST, JI-GIST patients had undergone emergency surgery more frequently (37.9% vs. 10.4%, p = 0.007). According to the NIH-Fletcher classification, the low or very-low risk group represents 17.2% of JI-GISTs as opposed to 37.6% of G-GISTs (p < 0.005). When the AFIP-Miettinen system was used the low or very-low group represented 17.2% of JI-GISTs vs. 58.4% in the G-GISTs group (p < 0.001). Both local recurrence (24.1% vs. 12.5%, p < 0.05) and metastatic rate (34.5% vs. 22.9%, p < 0.05) were higher in the JI-GIST group than in G-GIST. 5- and 10-year DFS and 10-year OS rate were lower for JI-GIST (54.5% and 39.6% vs. 77.2% and 60.8%, and 57.9% vs. 65%, respectively, p < 0.05).

CONCLUSIONS

The observed differences between both groups in DFS and OS rates at long term could be attributed to the effect of imatinib.

Establishment of patient-derived xenografts from patients with gastrointestinal stromal tumors: analysis of clinicopathological characteristics related to engraftment success

Patient-derived xenografts (PDXs) can represent the heterogeneity and histological characteristics of tumors and are thus useful for testing the efficacy of anti-cancer drugs; however, PDXs are difficult to generate, especially for gastrointestinal stromal tumor (GIST). We analyzed the clinicopathologic factors associated with the successful establishment of GIST PDX in NOD.Cg-Prkdc^scid IL2rg^tm1Wjl/SzJ mice. We used 185 GIST tumor fragments from patients who underwent surgical resection prior to (n = 66; 35.7%) and after treatment (n = 119; 64.3%) with tyrosine kinase inhibitors. The overall success rate of PDX establishment was 17%; in univariate analysis, engraftment success was associated with after TKI treatment, larger tumor size, higher mitotic count, higher Ki-67 index, higher cellularity, presence of tumor necrosis, primary mutations in KIT exon 11, and originating from metastatic lesions. In multivariate analysis, higher Ki-67 index, after TKI treatment, and larger tumor size were independent factors for engraftment success. Immunohistochemistry in representative samples further corroborated the above results. These results will be useful in the establishment of PDX models from GISTs.

A giant jejunal gastrointestinal stromal tumor misconceived as pancreatic cystic neoplasm: A case report

INTRODUCTION

Gastrointestinal stromal tumors (GISTs), although not common in gastrointestinal (GI) tumors, constitute the most frequent mesenchymal tumors of the GI tract. This report describes a patient with a large sporadic GIST at proximal jejunum that mimicked the pancreatic cystic neoplasm.

CASE PRESENTATION

We report a 59-year-old female patient with unexplained weight loss and palpable left upper quadrant abdominal mass for 6 months. Computed tomography (CT) scan demonstrated a heterogeneously mass measuring 10 cm in a maximal diameter at pancreatic body and tail. Laparotomy was done, and the tumor was found at proximal jejunum closed to the ligament of Treitz, so en bloc resection of the tumor was done. The pathological and immunohistochemical study confirmed GISTs.

DISCUSSION

Although most GISTs are originated from the intestine, they frequently arise from the stomach, the duodenum and rarely from the jejunum. And jejunal GISTs are usually asymptomatic. The misdiagnosis as mucinous cystadenoma of this case might be due to the proximity of the tumor to the body and tail of pancreas, and compressing the adjacent organ due to its large size.

CONCLUSION

GISTs are most frequently small and arising from the stomach. GISTs are rarely present as a large tumor of the jejunum, and particularly mimicked a pancreatic tumor.

Malignant jejunal gastrointestinal stromal tumor with history of prostate cancer: A case report

RATIONALE

The problem of the coexistence of gastrointestinal stromal tumor (GIST) with other neoplasms is complex, and carcinomas of prostate is one of the common types of GIST-associated cancers. Doubling time of GIST is about 3.9 months for high-risk GIST, and the treatment paradigm for GIST has required the integration of surgery and molecular therapy.

PATIENT CONCERNS

A 70-year-old man with postoperative history of prostate cancer experienced fast-growing malignant jejunal GIST with multiple peritoneal metastases within 1 year.

DIAGNOSES

Enhanced computed tomography (CT) detected a neoplasm of small intestine with multiple peritoneal nodules and postoperative pathology confirmed GIST.

INTERVENTIONS

Oral imatinib after surgery, at 400 mg per day, was used for 4 years.

OUTCOMES

The patient remains well, and the peritoneal nodules located in front of the rectum disappeared gradually.

LESSONS

Physicians should be aware of possibility of GIST in patients with prostate cancer and can perform abdominal examination in these patients. For postoperative patients with prostate cancer, an yearly or half-yearly abdominal and pelvic cavity examination can be performed. Suspicion and timely work-up is necessary in these postoperative prostate cancer patients, especially when they have abdominopelvic pain.

Is the Surgical Margin in Gastrointestinal Stromal Tumors Different?

Background

Radical surgical excision is the mainstay of therapy of primary, nonmetastatic gastrointestinal stromal tumors (GIST) and margin status after surgery is a significant prognostic factor.

Methods and Results

The aim of this paper is to review principles in primary GIST surgery, i.e. differences between R0, R1, and R2 resection, to describe how surgical margin status and tumor intraperitoneal rupture influence the patients' outcome, and how this may be effected by neoadjuvant and adjuvant treatment in locally advanced tumors. A systematic search of literature published between 2000 and 2018 was performed regarding this topic.

Conclusion

Correct interpretation of margin status after surgery can be affected by many factors during operation and preparation of tissue.

Small bowel gastrointestinal stromal tumor: a retrospective study of 32 cases at a single center and review of the literature

Background

Gastrointestinal stromal tumor (GIST) is a rare tumor of the small bowel, which can be difficult to diagnose and has a varied clinical outcome.

Purpose

This is a retrospective review of the diagnosis, management, and clinical outcome of 32 patients diagnosed with primary small bowel GIST from a single center and a comparison of the findings with previously published cases.

Patients and methods

Retrospective review of data from patient clinical records, endoscopic and imaging findings, surgical procedures, tumor histology and immunohistochemistry, and clinical outcome was conducted.

Results

Data of 32 patients with a median age of 56 years including 50% men and women were reviewed. The majority (29/32) were symptomatic at presentation, with the main symptom being gastrointestinal bleeding (15/32). Imaging detection rates included ultrasound (0%), magnetic resonance imaging (0%), computed tomography (54.8%), computed tomography angiography (71.4%), and double-balloon enteroscopy (88.9%). The mean tumor diameter was 5.3 cm; 4 tumors were located in the duodenum, 21 in the jejunum, and 7 in the ileum. Based on the tumor size and mitotic index, 5 (15.6%), 15 (46.9%), 0 (0%), and 12 (37.5%) patients were classified into very low-risk, low-risk, intermediate-risk, and high-risk groups. Immunohistochemistry showed positive expression for CD117 (100%), CD34 (81.2%), DOG1 (93.8%), smooth muscle actin (37.5%), S100 (9.4%), and desmin (6.2%). Twenty-five patients (78.1%) were treated with open surgical tumor resection; seven patients (21.9%) underwent laparoscopic surgery. Postoperative complications that occurred in seven patients (21.9%) were resolved with conservative management. Four patients were treated with postoperative imatinib. At median follow-up of 30 months, two patients were died.

Conclusion

The findings from this case series, combined with the findings from previously published cases, provide an update on the current status of the diagnosis and the therapeutic approaches that might lead to improvement in prognosis for patients who present with primary small bowel GIST.

Clinicopathological Features and Prognosis of Gastrointestinal Stromal Tumor Located in the Jejunum and Ileum

BACKGROUND

Data about the clinicopathological features and prognosis of gastrointestinal stromal tumors (GISTs) located in jejunum and ileum are lacking. The present study aims to investigate the features and prognosis of jejunal and ileal GISTs based on the Surveillance, Epidemiology, and End Results (SEER) database.

PATIENTS AND METHODS

Cases of jejunal and ileal GISTs were extracted from SEER database. Clinicopathological characteristics and survival data of patients were recorded. The clinicopathological features and prognosis of patients were analyzed.

RESULTS

There were 399 male (56.8%) and 303 female (43.2%). The median age was 60 years (17-96). Four hundred and seventy-two tumors were located in the jejunum (67.2%) and 230 tumors in the ileum (32.8%). The median tumor size was 7.0 cm (0.5-90). The 5-, 10-, and 20-year disease specific survival (DSS) was 84.4, 71.2, and 54.2% respectively. Clinicopathological features were comparable between tumors located in the jejunum and ileum (all p > 0.05) except gender and tumor size (both p < 0.05). Jejunal GISTs, rather than ileal GISTs (p = 0.043), were commonly found in the males. The tumor size of jejunal GISTs was smaller than that of ileal GISTs (p = 0.010). The DSS of jejunal GISTs was comparable to that of ileal GISTs (p = 0.269).

CONCLUSIONS

Jejunal GISTs were more common than ileal GISTs. The prognosis was comparable between jejunal and ileal GISTs.

Ki-67 Labeling Index can be used as a Prognostic Marker in Gastrointestinal Stromal Tumor: A Systematic Review and Meta-Analysis

Purpose

The aim of this study was to investigate the prognostic relevance of the Ki-67 labeling index (LI) in gastrointestinal stromal tumor (GIST) through a systematic review, meta-analysis and diagnostic test accuracy review.

Method

The study included 1,967 GIST cases from 24 eligible studies. We investigated the correlation between high Ki-67 LI and survival and the proper criteria for high Ki-67 LI. In addition, a diagnostic test accuracy review was conducted to evaluate the predictive role of high Ki-67 LI for higher risk of tumor recurrence.

Results

A high Ki-67 LI was significantly correlated with worse disease-free survival (DFS) (hazard ratio [HR] 3.658, 95% confidence interval [CI] 2.687-4.979, p<0.001) and overall survival (OS) (HR 3.730, 95% CI 2.819-4.936, p<0.001). With regard to DFS and OS, the subgroup with a cutoff value of >4% for high Ki-67 LI had a higher HR than the subgroup with a ≤4% cutoff. In the diagnostic test accuracy review, a high Ki-67 LI was significantly correlated with higher risk of tumor recurrence (pooled sensitivity = 0.44, pooled specificity = 0.87, area under the curve on the summary receiver operating characteristic curve = 0.656).

Conclusions

Our results showed that a high Ki-67 LI was significantly correlated with worse prognosis and higher risk of tumor recurrence in GIST. Further prospective studies of the prognostic role of Ki-67 LI are necessary prior to application in clinical practice.

Prognostic role of microscopically positive margins for primary gastrointestinal stromal tumors: a systematic review and meta-analysis

The impact and management of microscopically positive margins in gastrointestinal stromal tumors (GISTs) remain unclear. The aim of this study is to estimate the prognostic value of surgical margins for disease-free survival (DFS) and overall survival (OS) in patients with primary GISTs. Twelve studies with 1985 GIST patients were included. The overall recurrence rate in R1 resection and R0 resection group was 0.364 (95% CI 0.299-0.429) and 0.296 (95% CI 0.161-0.430), respectively. Meta-analysis confirmed that a microscopically positive margin could significantly impact the disease-free survival (HR 1.596, 95% CI 1.128-2.258; I(2) = 37.5%, P value = 0.091), but had no influence on overall survival (HR 1.430, 95% CI 0.608-3.363; I(2) = 60.8%, P value = 0.013). Importantly, subgroup analysis revealed that adjuvant imatinib treatment could attenuate the risk of recurrence for primary GIST patients who received R1 resection. (HR 1.308, 95% CI 0.583-2.935; I(2) = 53.2%, P value = 0.074). The level of evidence achieved in this study was "moderate" for DFS and "low" for OS. In conclusion, this study revealed that a microscopically positive margin is an unfavorable prognostic factor for GIST patients with R1 resection, and adjuvant imatinib treatment is proved to be effective.

Ginsenoside Re inhibits pacemaker potentials via adenosine triphosphate-sensitive potassium channels and the cyclic guanosine monophosphate/nitric oxide-dependent pathway in cultured interstitial cells of Cajal from mouse small intestine

BACKGROUND

Ginseng belongs to the genus Panax. Its main active ingredients are the ginsenosides. Interstitial cells of Cajal (ICCs) are the pacemaker cells of the gastrointestinal (GI) tract. To understand the effects of ginsenoside Re (GRe) on GI motility, the authors investigated its effects on the pacemaker activity of ICCs of the murine small intestine.

METHODS

Interstitial cells of Cajal were dissociated from mouse small intestines by enzymatic digestion. The whole-cell patch clamp configuration was used to record pacemaker potentials in cultured ICCs. Changes in cyclic guanosine monophosphate (cGMP) content induced by GRe were investigated.

RESULTS

Ginsenoside Re (20-40μM) decreased the amplitude and frequency of ICC pacemaker activity in a concentration-dependent manner. This action was blocked by guanosine 5'-[β-thio]diphosphate [a guanosine-5'-triphosphate (GTP)-binding protein inhibitor] and by glibenclamide [an adenosine triphosphate (ATP)-sensitive K(+) channel blocker]. To study the GRe-induced signaling pathway in ICCs, the effects of 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (a guanylate cyclase inhibitor) and RP-8-CPT-cGMPS (a protein kinase G inhibitor) were examined. Both inhibitors blocked the inhibitory effect of GRe on ICC pacemaker activity. L-NG-nitroarginine methyl ester (100μM), which is a nonselective nitric oxide synthase (NOS) inhibitor, blocked the effects of GRe on ICC pacemaker activity and GRe-stimulated cGMP production in ICCs.

CONCLUSION

In cultured murine ICCs, GRe inhibits the pacemaker activity of ICCs via the ATP-sensitive potassium (K(+)) channel and the cGMP/NO-dependent pathway. Ginsenoside Re may be a basis for developing novel spasmolytic agents to prevent or alleviate GI motility dysfunction.

Usefulness of laparoscopic side-to-side duodenojejunostomy for gastrointestinal stromal tumors located at the duodenojejunal junction

BACKGROUND

Surgery for gastrointestinal stromal tumor (GIST) at the duodenojejunal junction is a technically challenging and difficult procedure because of the anatomical complexity. When it comes to laparoscopic surgery, it is more challenging than open surgery. This study aimed to introduce our laparoscopic procedure and to evaluate its clinical implication by comparing with open procedures.

METHOD

Between 2003 and 2013, 19 patients underwent segmental resection for a GIST at the duodenojejunal junction: laparoscopic segmental resection with side-to-side duodenojejunostomy (n = 8) and open surgery (n = 11). Clinicopathological findings, operation details, and postoperative outcomes were compared.

RESULTS

Both groups were comparable in demographics and clinicopathological characteristics. Postoperative hospital stay of the laparoscopic group (6.3 days) was significantly shorter than the open group (15.7 days, P = 0.008) while no significant differences were observed regarding estimated blood loss, operation time, and morbidity. All patients in both groups underwent curative resection without operative mortality. Two patients experienced recurrence after open surgery whereas none of the patients after laparoscopic duodenojejunostomy had recurrence with a median follow-up period of 36 months.

CONCLUSION

Laparoscopic segmental resection with side-to-side duodenojejunostomy for a GIST at the duodenojejunal junction is a safe, feasible, and effective alternative to open approach, providing benefits of minimally invasive surgery.

Interventional digital subtraction angiography for small bowel gastrointestinal stromal tumors with bleeding

AIM: To retrospectively evaluate the diagnostic efficacy of interventional digital subtraction angiography (DSA) for bleeding small bowel gastrointestinal stromal tumors (GISTs).

METHODS: Between January 2006 and December 2013, small bowel tumors in 25 consecutive patients undergoing emergency interventional DSA were histopathologically confirmed as GIST after surgical resection. The medical records of these patients and the effects of interventional DSA and the presentation and management of the condition were retrospectively reviewed.

RESULTS: Of the 25 patients with an age range from 34- to 70-year-old (mean: 54 ± 12 years), 8 were male and 17 were female. Obscure gastrointestinal bleeding, including tarry or bloody stool and intermittent melena, was observed in all cases, and one case also involved hematemesis. Nineteen patients required acute blood transfusion. There were a total of 28 small bowel tumors detected by DSA. Among these, 20 were located in the jejunum and 8 were located in the ileum. The DSA characteristics of the GISTs included a hypervascular mass of well-defined, homogeneous enhancement and early developed draining veins. One case involved a complication of intussusception of the small intestine that was discovered during surgery. No pseudoaneurysms, arteriovenous malformations or fistulae, or arterial rupture were observed. The completely excised size was approximately 1.20 to 5.50 cm (mean: 3.05 ± 1.25 cm) in maximum diameter based on measurements after the resection. There were ulcerations (n = 8), erosions (n = 10), hyperemia and edema (n = 10) on the intra-luminal side of the tumors. Eight tumors in patients with a large amount of blood loss were treated with transcatheter arterial embolization with gelfoam particles during interventional DSA.

CONCLUSION: Emergency interventional DSA is a useful imaging option for locating and diagnosing small bowel GISTs in patients with bleeding, and is an effective treatment modality.

Successful treatment of bleeding large duodenal gastrointestinal stromal tumour in a patient under dual antiplatelet therapy after recent drug-eluting coronary stent implantation

We report a case of a 69-year-old man who started dual antiplatelet therapy (APT) with aspirin and clopidogrel after recent implantation of drug-eluting coronary stent and developed massive bleeding due to large duodenal gastrointestinal stromal tumour (GIST). Following endoscopic haemostasis and discontinuation of dual APT, neoadjuvant chemotherapy with imatinib was started under continuation of 'single' APT with aspirin. A good chemotherapeutic response was achieved without recurrence of bleeding, and subsequent less invasive surgical resection of the tumour was performed, while preoperative single APT was continued for prevention of stent thrombosis. The patient recovered well without any thromboembolic or bleeding events. Neoadjuvant imatinib therapy and subsequent less invasive surgery under continuation of APT is one of the preferred approaches for patients with duodenal GIST with severe thromboembolic comorbidities, as in the current case.

Double-balloon endoscopy for diagnosis of small intestinal disorders: A systematic review of data over the first decade of use

AIM: To systematically analyze data on diagnostic rate, observation scope, and complications of double-balloon endoscopy (DBE) for small bowel diseases, and to further evaluate its clinical value and security.

METHODS: A total of 1036 patients (585 men and 451 women) with suspected or known small-bowel diseases underwent 1202 DBE procedures (oral 589, anal 613, both approaches 184) under anesthesia with propofol at our institution over the past decade.

RESULTS: The success rate of DBE was 99.2% (1193/1202), and the positive diagnostic yield was 84.5% (875/1036). The main diagnosis was polyps and tumors (391/1202; 32.5%), erosions and ulcerations (246/1202; 20.4%), and angiodysplasia (52/1202; 4.32%). The mean duration of the procedure was 78 min ± 43 min (30-180 min). On average, 231 cm ± 74 cm of the small bowel was visualized by using the oral route and 176 cm ± 69 cm by using the anal route (P < 0.05). Most common lesions detected in patients with OGIB (obscure gastrointestinal bleeding) were ulcers and erosions (57/218; 26.1%), vascular diseases (33/218; 15.1%), and tumors and polyps (28/218; 12.8%). Among 63 small bowel tumor cases, 45 were malignant (45/63; 71%) and 18 were benign (18/63; 29%). Histopathology was consistent with the endoscopic diagnosis in 87.5% (63/72) of patients with small bowel tumors. Severe complications were observed in 11/1202 (0.915%) of cases. A minority of patients complained of mild sore throat, anal pain or abdominal distension after the DBE procdure.

CONCLUSION: Our retrospective analysis shows that DBE is a safe and effective method to diagnose small bowel disorders by visualization and tissue sampling to assist in diagnosis of etiology.

Gastrointestinal stromal tumors (GIST) related emergencies

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, accounting for 1-3% of all gastrointestinal malignancies. Throughout the whole length of the gastrointestinal tract, GIST arises most commonly from the stomach followed by small bowel. The clinical presentations of GIST are highly variable according to their site and size. The most frequent symptoms are anemia, weight loss, gastrointestinal bleeding, abdominal pain and massrelated symptoms. Patients may present with acute abdomen, obstruction, perforation or rupture and peritonitis. Surgical resection is the "gold standard" for therapy of GIST. Recently, targeted therapy with inhibitors of tyrosine kinase receptors (imatinib) has been introduced for the management of advanced and metastatic tumors.

PURPOSE

The aim of this work is to present the experience of the Gastrointestinal Surgery Unit, Alexandria Faculty of Medicine in the management of patients with GIST related emergencies.

PATIENTS AND METHODS

This study was carried out on all patients with gastrointestinal stromal tumors who presented to the Gastrointestinal Surgery Unit, Main Alexandria University Hospital in an emergency situation during the period from January 2005 till December 2012. All patients' data, clinical presentations, radiological and endoscopic data, surgical procedures, complications, and survival data were collected, reviewed and analyzed. After approval of local ethics committee, all patients included in the study were informed well about the procedure and an informed written consent was obtained from every patient before carrying the procedure.

RESULTS

Between January 2005 and December 2012; 92 patients (54 males and 38 females) were admitted with different emergency presentations of clinically and radiologically suspected GISTs. The tumors were located in the stomach in 49 patients, in the duodenum in 6 patients, in the small intestine in 27 patients, in the small intestinal mesentery in 4 patients, in the colon in 3 patients and in the rectum in 3 patients. The most frequent presenting symptom was gastrointestinal bleeding in 45 patients. Twenty-six patients presented with intestinal obstruction, 14 patients with intraperitoneal hemorrhage and 7 patients with rupture and peritonitis. Ninety patients were operated upon. Two patients presented with extensive GIST, and were not candidate for surgical treatment. All operated patients underwent surgical resection. Complete macroscopic resection was achieved in 86 patients (95.6%), while 4 patients (4.4%) had incomplete resection. All over 11 patients developed metastases, or recurrence. The 3 and 5-years overall survival rates for all patients, using the Kaplan-Meier actuarial curve, were 92.1% and 81.4% respectively. The 3 and 5-years disease-free survival rates for all patients were 73.2% and 64.5% respectively.

CONCLUSION

Although GISTs are uncommon, their incidence is probably increasing especially their emergency presentations. The emergency surgeon must be acquainted with the disease, its emergency presentation and principles of surgery in the presence of GIST tumors. Early diagnosis and treatment would save life of many patients who presented with GIST related emergencies. Surgery is still the gold standard treatment in localized GIST, although the percentage of relapse is not low even after radical surgery. The prognosis is strictly related to size and completeness of surgical resection. We strongly advocate that all patients with a GIST be carefully and regularly followed-up for an indefinite period. The large number of patients in this series is an alarming signal for further studies to elucidate the pathogenesis of this disease.

Characteristics of nobiletin-induced effects on jejunal contractility

Nobiletin, a citrus polymethoxylated flavone, exhibits multiple biological properties including anti-inflammatory, anti-carcinogenic, and anti-insulin resistance effects. The present study found that nobiletin exerted significant stimulatory effects on the contractility of isolated rat jejunal segments in all 6 different low contractile states, and meanwhile significant inhibitory effects in all 6 different high contractile states, showing characteristics of bidirectional regulation (BR). Nobiletin-exerted BR on jejunal contractility was abolished in the presence of c-kit receptor tyrosine kinase inhibitor imatinib or Ca(2+) channel blocker verapamil. In the presence of neuroxin tetrodotoxin, nobiletin only exerted stimulatory effects on jejunal contractility in both low and high contractile states. Hemicholinium-3 and atropine partially blocked nobiletin-exerted stimulatory effects on jejunal contractility in low-Ca(2+)-induced low contractile state. Phentolamine or propranolol or l-NG-nitro-arginine significantly blocked nobiletin-exerted inhibitory effects on jejunal contractility in high-Ca(2+)-induced high contractile state respectively. The effects of nobiletin on myosin light chain kinase (MLCK) mRNA expression, MLCK protein content, and myosin light chain phosphorylation extent were also bidirectional. In summary, nobiletin-exerted BR depends on the contractile states of rat jejunal segments. Nobiletin-exerted BR requires the enteric nervous system, interstitial cell of Cajal, Ca(2+), and myosin phosphorylation-related mechanisms.

Clinicopathologic factors predicting outcomes in patients with gastrointestinal stromal tumors of the rectum and colon

Limited information is available concerning the clinicopathologic profile of colorectal gastrointestinal stromal tumors (GISTs), which are relatively rare, as well as survival rates following surgical resection. The present study was designed to describe the clinicopathologic characteristics of patients with colorectal GISTs and identify potential factors that may predict postoperative survival outcomes. We reviewed the medical records of 67 patients with colorectal GISTs who underwent surgical resection between January 2000 and December 2012. Clinicopathologic factors affecting overall survival were assessed using the Kaplan-Meier method and multivariate Cox proportional hazards models. The median age at diagnosis was 57 years (range, 32-79 years), with a male-to-female ratio of 1.68. Tumor size varied from 0.2 to 11 cm, with a median size of 5.7 cm. Sixty-two tumors (93%) were positive for CD117, 53 (79%) for CD34, 6 (9%) for PDGFRA, 15 (22%) for SMA, 5 (8%) for S100, and 39 (58%) for vimentin. The overall median survival time was 54 months (95% confidence interval, 32-59 months), and the 1-, 3-, and 5-year overall survival rates were 89.6, 63.9, and 34.4%, respectively. High-risk tumors (determined by histologic grade, size, and other histologic variables) were associated with poor prognosis (hazard ratio, 1.83; 95% confidence interval, 1.21-2.78), and patients who received adjuvant treatment with imatinib had significantly longer median overall survival times than patients who did not (hazard ratio, 0.43; 95% confidence interval, 0.24-0.80). In patients with colorectal GISTs, high-risk tumor histologic grade can predict poor prognosis, and patients may benefit from adjuvant treatment with imatinib. Findings from the present study may provide information to establish evidence-based management strategies for colorectal GISTs.

Treatment Results of Small Intestinal Gastrointestinal Stromal Tumors Less than 10 cm in Diameter: A Comparison between Laparoscopy and Open Surgery

Purpose

To evaluate the technical feasibility and oncologic safety, we assessed the short-term and long-term outcomes of laparoscopic resection of the small bowel gastrointestinal stromal tumors smaller than 5 cm by comparing those of open surgery by subgroup analysis based on tumor size.

Materials and Methods

From November 1993 to January 2011, 41 laparoscopic resections were performed among the 95 patients who underwent resection of small intestine ≤10 cm in diameter. The clinicopathologic features, perioperative outcomes, recurrences and survival of these patients were reviewed.

Results

The postoperative morbidity rates were comparable between the 2 groups. Laparoscopic surgery group showed significantly shorter operative time (P=0.004) and duration of postoperative hospital stay (P<0.001) than open surgery group and it was more apparent in the smaller tumor size group. There were no difference in 5-year survival for the laparoscopic surgery versus open surgery groups (P=0.163), and in 5-year recurrence-free survival (P=0.262). The subgroup analysis by 5 cm in tumor size also shows no remarkable differences in 5-year survival and recurrence-free survival.

Conclusions

Laparoscopic resection for small bowel gastrointestinal stromal tumors of size less than 10 cm has favorable short-term postoperative outcomes, while achieving comparable oncologic results compared with open surgery. Thus, laparoscopic approach can be recommended as a treatment modality for patients with small bowel gastrointestinal stromal tumors less than 10 cm in diameter.

Clinical outcomes of gastrointestinal stromal tumor in southern Thailand

AIM

To review a single institutional experience in clinical management of gastrointestinal stromal tumors (GIST) and analyze for factors determining treatment outcome.

METHODS

Clinicopathological data of patients with a diagnosis of GIST who were treated at our institute during November 2004 to September 2009 were retrospectively reviewed.

RESULTS

Ninety-nine cases were included in the analysis. Primary tumor sites were at the stomach in and small bowel in 44% and 33%, respectively. Thirty-one cases already had metastasis at presentation and the most common metastatic site was the liver. Sixty-four cases (65%) were in the high-risk category. Surgical treatment was performed in 77 cases (78%), 3 of whom received upfront targeted therapy. Complete resection was achieved in 56 cases (73% of operative cases) and of whom 27 developed local recurrence or distant metastasis at a median duration of 2 years. Imatinib was given as a primary therapy in unresectable cases (25 cases) and as an adjuvant in cases with residual tumor (21 cases). Targeted therapy gave partial response in 7 cases (15%), stable disease in 27 cases (57%) and progressive disease in 13 cases (28%). Four-year overall survival was 74% (95% CI: 61%-83%). Univariate survival analysis found that low-risk tumor, gastric site, complete resection and response to imatinib were associated with better survival.

CONCLUSION

The overall outcomes of GIST can be predicted by risk-categorization. Surgery alone may not be a curative treatment for GIST. Response to targeted therapy is a crucial survival determinant in these patients.

Clinical practice guidelines for patients with gastrointestinal stromal tumor in Taiwan

For many years, the understanding of gastrointestinal stromal tumors (GISTs), which are the most common mesenchymal tumors of the gastrointestinal tract, has been very limited. However, it is now possible to provide a more precise definition through the use of pathology classification and molecular techniques. Coupled with the advancement of clinical practice, especially the development of targeted therapy, there is now a much better insight into its treatment. At present, organizations such as the National Comprehensive Cancer Network in the USA and the European Society for Medical Oncology in Europe have established a consensus and drawn up guidelines for the diagnosis, treatment, and follow-up of GISTs.With experts coming from various districts in Taiwan and combining the most recent clinical data and experiences, the Taiwan Surgical Society of Gastroenterology drafted the first national GIST treatment guidelines after a consensus meeting in 2007. Following subsequent advances in GIST diagnosis and treatment, further revisions and modifications have been made to the original guidelines. We present here the updated consensus and recommendations of the Taiwan Surgical Society of Gastroenterology for the diagnosis and treatment of GIST. We hope these guidelines can help enhance the quality of diagnosis, treatment, and care of patients with GIST in Taiwan.

Prognostic factors for survival post surgery for patients with gastrointestinal stromal tumors

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms located in the alimentary tract. Our aim was to assess the influence of prognostic factors on survival in patients surgically treated for GISTs.

STUDY

One hundred and five patients treated between January 1989 and December 2008 were available for study. A retrospective analysis of prognostic factors (age, gender, mitotic index, tumor location, tumor size, risk of malignant behavior, and coexisting other neoplasm) was performed. Univariate and multivariate survival analyses were undertaken.

RESULTS

Univariate analyses revealed the importance of patient gender (p = 0.007), disease location (p = 0.055), mitotic index (p = 0.054) and coexistence with other neoplasms (p = 0.004). However, multivariate analysis showed 3 independently statistically significant factors: coexistence with other neoplasm (RR = 3.53, p = 0.004), male gender (RR = 2.60, p = 0.011) and mitotic index ≥10/50 HPF, (RR = 2.60, p = 0.042).

CONCLUSIONS

Our study has shown that male gender, a high mitotic index ≥10/50 HPF, and coexistence with other malignant neoplasms were independent poor prognostic factors in patients with GIST. The presence of middle or lower gut disease location leads to an increased risk of mortality when compared with the upper gut.

Surveillance strategies for gastrointestinal stromal tumors

Although only 10-30% of gastrointestinal stromal tumors (GISTs) are clinically malignant, all have some degree of malignant potential. The management of high risk patients should be evidence based. However, prospective data and a consensus for guidelines concerning the screening of asymptomatic high risk patients and surveillance following multidisciplinary treatment do not exist. This review provides an overview of GIST, with an emphasis on the available data regarding screening and surveillance of certain populations with GISTs.

Unusual features of gastrointestinal stromal tumor on PET/CT and CT imaging

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. It can be benign or malignant in behavior. Stomach, being the most common site (70%) for GISTs, is followed by the small intestine (20%). Anorectal, colonic, and esophageal GISTs are uncommon, whereas extraintestinal GISTs are extremely rare. The presenting symptoms are highly dependent on tumor size and location, although a large number of GISTs are asymptomatic. The purpose of this article is to highlight the unusual characteristics of GISTs illustrated by PET/CT and CT imaging. These characteristics are organized into (1) unusual tumor location, (2) unusual clinical presentation, and (3) unusual sites of metastasis. Knowing the uncommon features of GISTs is important, as they are more often seen nowadays with the increasingly important role of PET/CT and CT in GIST management; and these tumors are associated with a poorer prognosis and unwanted delay in diagnosis is avoidable. With the availability of effective treatment by imatinib mesylate, a prompt and early diagnosis is essential for disease control. All GISTs illustrated in this article are pathologically proven.

Prognostic factors and outcome of resected patients with gastrointestinal stromal tumors of small intestine

We document the clinical behavior of gastrointestinal stromal tumors (GISTs) of the small intestine and identify predictors for long-term disease-free survival (DFS) for small intestine GIST patients. From December 2001 to 2008, 114 consecutive patients with mesenchymal tumors involving the small intestine were enrolled. There were 54 male and 60 female (50.6%) patients. After a median follow-up period of 36 months (ranging from 12 to 96 months), recurrence was noted in 19 patients (16.7%) with a median time of 20 months (ranging from 7 to 50 months). There were 12 patients (10.5%) who died of GISTs with a median time from recurrence to death of 14 months (ranging from 8 to 22 months). Univariate analysis by log-rank test indicated that tumor size and mitotic activity were statistically significant for DFS (P = 0.001 and 0.036, respectively). Tumor size was the only significant predictive factor for DFS according to multivariate analysis (P = 0.006). Small tumor size, indicating low risk, predicted more favorable DFS of small intestine GIST patients who underwent curative resection.

[Controversies in the surgical treatment of primary gastrointestinal stromal tumours (GIST)]

It is estimated that 50% of GIST are located at the time of their diagnosis. A complete surgical resection can be performed in up to 95% of these cases, making this the most important prognostic factor. This surgery must fulfil a series of technical requirements so as to be really effective, as it has to be R0, with no tumour rupture, with preservation of the pseudo-capsule, etc. Although the majority of GIST are gastric, their location in other anatomical areas, such as the oesophagus, duodenum or rectum, require the surgeon to use more complex techniques. Laparoscopy is increasingly used; however, we must avoid its use, due to there being few experienced groups or if there are large tumours. The use of neoadjuvant therapy has revived great interest by allowing to resection tumours that were once non-resectable or in very compromised anatomical locations, with less aggressive surgery. The use of pre-surgical biopsy is not exempt from serious risks, thus it should only be used for establishing a neoadjuvant treatment or if there are diagnostic doubts with other diseases in high risk patients.

Duodenal gastrointestinal stromal tumor: clinical, pathologic, immunohistochemical characteristics, and surgical prognosis

OBJECTIVE

Gastrointestinal stromal tumors (GISTs) occur rarely in the duodenum. The characteristics of duodenal GIST have not been well clarified. The aim of this study is to clarify the characteristics and surgical prognosis of patients with primary duodenal GIST.

METHODS

Data of patients with surgically treated primary duodenal GIST were retrospectively analyzed. Immunohistochemical expressions of p53, p16, and Ki-67 were evaluated to explain the prognosis.

RESULTS

Compared with gastric or small intestinal GISTs in historical studies, duodenal GISTs had a relatively smaller size, lower mitotic count, lower Ki-67 LI, lower p16 loss, and similar p53 expression. The 1- and 3-year recurrence-free survival rates of patients with complete resection were 100 and 95.2%.

CONCLUSION

Patients with completely resected primary duodenal GIST seem to have a more favorable prognosis. This may be related to the different expressions of some immunohistological makers compared with GISTs of other locations.

Preoperative diagnosis of obscure gastrointestinal bleeding due to a GIST of the jejunum: a case report

Gastrointestinal stromal tumours (GISTs) are rare mesenchymal neoplasms affecting the digestive tract or nearby structures within the abdomen. We present a case of a 66-year-old female patient who presented with obscure anemia due to gastrointestinal bleeding and underwent exploratory laparotomy during which a large GIST of the small intestine was discovered. Examining the preoperative results of video capsule endoscopy, computed tomography, and angiography and comparing them with the operative findings we discuss which of these investigations plays the most important role in the detection and localization of GIST. A sort review of the literature is also conducted on these rare mesenchymal tumours.

Development and validation of a prognostic nomogram for recurrence-free survival after complete surgical resection of localised primary gastrointestinal stromal tumour: a retrospective analysis

BACKGROUND

Adjuvant imatinib mesylate prolongs recurrence-free survival (RFS) after resection of localised primary gastrointestinal stromal tumours (GIST). We aimed to develop a nomogram to predict RFS after surgery in the absence of adjuvant therapy to help guide patient selection for adjuvant imatinib therapy.

METHODS

A nomogram to predict RFS based on tumour size (cm), location (stomach, small intestine, colon/rectum, or other), and mitotic index (<5 or > or =5 mitoses per 50 high-power fields) was developed from 127 patients treated at Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY, USA. The nomogram was tested in patients from the Spanish Group for Research on Sarcomas (GEIS; n=212) and the Mayo Clinic, Rochester, MN, USA (Mayo; n=148). The nomogram was assessed by calculating concordance probabilities and testing calibration of predicted RFS with observed RFS. Concordance probabilities were also compared with those of three commonly used staging systems.

FINDINGS

The nomogram had a concordance probability of 0.78 (SE 0.02) in the MSKCC dataset, and 0.76 (0.03) and 0.80 (0.02) in the validation cohorts. Nomogram predictions were well calibrated. Inclusion of tyrosine kinase mutation status in the nomogram did not improve its discriminatory ability. Concordance probabilities of the nomogram were better than those of the two NIH staging systems (0.76 [0.03] vs 0.70 [0.04, p=0.04] and 0.66 [0.04, p=0.01] in the GEIS validation cohort; 0.80 [0.02] vs 0.74 [0.02, p=0.04] and 0.78 [0.02, p=0.05] in the Mayo cohort) and similar to those of the AFIP-Miettinen staging system (0.76 [0.03] vs 0.73 [0.004, p=0.28] in the GEIS cohort; 0.80 [0.02] vs 0.76 [0.003, p=0.09] in the Mayo cohort). Nomogram predictions of RFS seemed better calibrated than predictions made with the AFIP-Miettinen system.

INTERPRETATION

The nomogram accurately predicts RFS after resection of localised primary GIST and could be used to select patients for adjuvant imatinib therapy.

Preoperative diagnosis of obscure gastrointestinal bleeding due to a GIST of the jejunum: a case report

Gastrointestinal stromal tumours are rare mesenchymal neoplasms affecting the digestive tract or nearby structures within the abdomen. We present a case of a 66-year-old female patient who presented with obscure anemia due to gastrointestinal bleeding and underwent exploratory laparotomy during which a large gastrointestinal stromal tumour of the small intestine was discovered. Examining the preoperative results of video capsule endoscopy, computed tomography, and angiography and comparing them with the operative findings we discuss which of these investigations plays the most important role in the detection and localization of gastrointestinal stromal tumours. A sort review of the literature is also conducted on these rare mesenchymal tumours.

Surgical therapy for gastrointestinal stromal tumours of the upper gastrointestinal tract

AIM

This study aimed to examine clinicopathological features and outcomes after primary resection of gastrointestinal stromal tumours (GIST) of the upper gastrointestinal tract

METHOD

Fifty consecutive patients were identified as having a mesenchymal tumour of the upper gastrointestinal tract resected at our institution, of which 47 were GISTs. The influence of clinicopathological variables on disease-free survival was evaluated using Kaplan-Meier estimates and Cox hazard model.

RESULTS

The median age was 62.8 (21.3-94.7). The commonest presenting symptoms were anaemia (43%) and pain (34%). Tumours were located in the stomach (64%), small bowel (34%) and oesophagus (2%). Median follow-up was 20.4 (2-106) months. Fletcher low/intermediate-risk tumours had a significantly better (p = 0.0008) 2- and 5-year actuarial survival of 100% compared with 88% and 58% for high-risk group. Recurrence-free survival at 2 and 5 years was 100% for low/intermediate-risk group compared with 68% and 45% for the high-risk group (p = 0.0008). Univariate analysis of predictors of recurrence identified male sex, high mitotic rate and tumour size as significant. Multivariate analysis showed high mitotic rate as the only poor prognosticator (Hazard ratio = 16.7, p = 0.02).

CONCLUSION

Surgical excision of low- and intermediate-grade GIST has an excellent prognosis. Surgery remains the mainstay of treatments, and high-grade tumours carry a significantly worse prognosis. High mitotic rates are an independent poor prognosticator.

Surgical management of gastrointestinal stromal tumours

BACKGROUND

Over the past decade, gastrointestinal stromal tumours (GISTs) have served as a model for the application of tyrosine kinase inhibitors in the treatment of solid neoplasms. Operative and medical management of GISTs is rapidly evolving, but current guidelines appear restricted to basic non-organ-specific recommendations.

METHODS

A PubMed search was made of the English literature from 1998 to 2008 for references containing the terms 'gastrointestinal stromal tumours' and 'surgery'. This paper reviews the various operative strategies so far reported for GISTs within the digestive tract.

RESULTS

Many original procedures tailored to the specific characteristics of these rare sarcomas have been reported. GISTs exhibit distinct features, in particular an absence of metastases within locoregional lymph nodes. Operations requiring extended lymph node dissection, typically designed for adenocarcinomas, such as gastrectomy with extended lymph node dissection, Whipple's procedure and total mesorectum excision, are inappropriate for treating GISTs originating from the stomach, duodenum and rectum respectively.

CONCLUSION

GISTs allow the possibility of performing oncologically adequate but limited (wedge; segmental) resections. Such surgery can be carried out in a variety of ways, such as open, laparoscopic, trans-sacral or endoscopic.

Multidisciplinary treatment of gastrointestinal stromal tumors

Gastrointestinal stromal tumor (GIST) has been recognized as a unique tumor only in the last decade. Although rare as a clinical entity, there is much interest in the pathology and treatment because the KIT protooncogene mutation common to most GISTs can be inhibited by imatinib mesylate. Diagnosing and treating GIST requires a multidisciplinary approach, given the combination of pathologic and radiographic evaluation, surgical treatment, and oncologic care required to successfully treat patients with GIST.

Deletions of chromosome 1p and 15q are associated with aggressiveness of gastrointestinal stromal tumors

BACKGROUND/PURPOSE

Site-dependent profiles of chromosome imbalances (CIs) have been reported in gastrointestinal stromal tumors (GISTs). However, the role of specific CIs in association with metastasis is not clear.

METHODS

Thirteen resected liver metastatic GISTs, including seven from the stomach and six from the small intestine, were analyzed using comparative genomic hybridization (CGH). The CIs associated with metastatic risk were assessed by comparing them with those identified in our previous study of 25 primary GISTs, including 14 from the stomach and 11 from the small intestine.

RESULTS

Synchronous detection of liver metastasis was found more often in patients with intestinal than gastric GIST (5/6 vs. 2/7, p = 0.048). When compared with the primary tumors, the CI profile of liver metastases was similar in the intestinal group, but became more complex in the gastric group. Deletions of chromosomes 1p and 15q were very common (> 80%) in primary and metastatic tumors of the intestinal group, and exhibited a trend towards increase in the metastatic tumors of the gastric group. Both groups had a doubling in the frequency of 22q deletion in the liver metastases, which was not significantly different. Other CIs, including 9p deletion, increased significantly in the liver metastases of the gastric group, but not in the intestinal group.

CONCLUSION

Our results, together with clinical findings, indicated a CGH profile associated with the intrinsic aggressiveness of the GISTs. Deletion of 1p and 15q play a critical role in the acquisition of aggressiveness during early GIST development.