Pattern of recurrence in patients with ruptured primary gastrointestinal stromal tumour

Tumor rupture of gastric gastrointestinal stromal tumors during endoscopic resection: a risk factor for peritoneal metastasis?

BACKGROUND AND STUDY AIMS

 Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract. Up to the present time, complete surgical excision has been the standard treatment for primary GISTs greater than 2 cm. It is well known that tumor rupture during surgery is an independent risk factor for peritoneal metastasis; however, it is not known whether the risk of peritoneal metastasis increases in cases where the tumor is ruptured during endoscopic resection.

PATIENTS AND METHODS

 A total of 195 patients treated for GIST between January 2014 and December 2016 in our hospital were enrolled in this study. They were divided into two groups according to whether the tumor was ruptured during endoscopic resection. The rate of peritoneal metastasis in patients in the two groups who also suffered perforation was investigated from the follow-up results.

RESULTS

 Approximately 55.4 % of all patients were female and the average age of the study group was 59.0 ± 10.3 years. Of the 195 patients, the tumors in 27 were ruptured and the remaining 168 patients underwent en bloc resection. There was no statistically significant difference in gender or age between the two groups. The median tumor size (maximum diameter) in all patients was 1.5 cm (0.3 - 5.0 cm): 2.5 cm (0.8 - 5.0 cm) and 1.4 cm (0.3 - 4.0 cm) in the tumor rupture group and en bloc resection group, respectively ( P  < 0.001). Most of the tumors were located in the gastric fundus. At a median follow-up of 18.7 ± 10.2 months, neither tumor recurrence (liver metastasis, peritoneal metastasis, local recurrence) nor mortality related to GISTs were detected.

CONCLUSIONS

 Tumor rupture during endoscopic resection of gastric GISTs may not be a risk factor for peritoneal metastasis.

Clinicopathological features, surgical strategy and prognosis of duodenal gastrointestinal stromal tumors: a series of 300 patients

BACKGROUND

The relatively low incidence of duodenal gastrointestinal stromal tumors (GISTs) and the unique anatomy make the surgical management and outcomes of this kind of tumor still under debate. Thus, this study aimed to explore the optimal surgical strategy and prognosis of duodenal GISTs.

METHODS

A total of 300 cases of duodenal GISTs were obtained from our center (37 cases) and from case reports or series (263 cases) extracted from MEDLINE. Clinicopathological features, type of resections and survivals of duodenal GISTs were analyzed.

RESULTS

The most common location of duodenal GISTs was descending portion (137/266, 51.5%). The median tumor size was 4 cm (0.1-28). Most patients (66.3%) received limited resection (LR). Pancreaticoduodenectomy (PD) was mainly performed for GISTs with larger tumor size or arose from descending portion (both P < 0.05). For both the entire cohort and tumors located in the descending portion, PD was not an independent risk factor for disease-free survival (DFS) and disease-specific survival (DSS) (both P > 0.05). Duodenal GISTs were significantly different from gastric GISTs with respect to tumor size, mitotic index and NIH risk category (all P < 0.05). The DFS and DSS of duodenal GISTs was significantly worse than that of gastric GISTs (both P < 0.05).

CONCLUSIONS

LR was a more prevalent surgical procedure and PD was mainly performed for tumors with larger diameter or located in descending portion. Type of resection was not an independent risk factor for the prognosis of duodenal GISTs. Prognosis of duodenal GISTs was significantly worse than that of gastric GISTs.

Gastrointestinal stromal tumors: A multidisciplinary challenge

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors located in the alimentary tract. Its usual manifestation is gastrointestinal bleeding. However, small asymptomatic lesions are frequently detected as incidental finding. Characteristically, most GISTs (> 95%) are positive for the KIT protein (CD117) by IHC staining and approximately 80%-90% of GISTs carry a mutation in the c-KIT or PDGFRA genes. Mutational analysis should be performed when planning adjuvant and neoadjuvant therapy, due to its possible resistance to conventional treatment. The arise of tyrosine kinase inhibitor has supposed a revolution in GISTs treatment being useful as adjuvant, neoadjuvant or recurrence disease treatment. That is why a multidisciplinary approach to this disease is required. The correct characterization of the tumor at diagnosis (the diagnosis of recurrences and the evaluation of the response to treatment with tyrosine kinase inhibitors) is fundamental for facing these tumors and requires specialized Endoscopist, Radiologists and Nuclear Medicine Physician. Surgery is the only potentially curative treatment for suspected resectable GIST. In the case of high risk GISTs, surgery plus adjuvant Imatinib-Mesylate for 3 years is the standard treatment. Neoadjuvant imatinib-mesylate should be considered to shrink the tumor in case of locally advanced primary or recurrence disease, unresectable or potentially resectable metastasic tumors, and potentially resectable disease in complex anatomic locations to decrease the related morbidity. In the case of Metastatic GIST under Neoadjuvant treatment, when there are complete response, stable disease or limited disease progression, complete cytoreductive surgery could be a therapeutic option if feasible.

Clinicopathological Features and Prognosis of Primary GISTs with Tumor Rupture in the Real World

Background

Patients with ruptured gastrointestinal stromal tumor (GIST) are recommended for imatinib adjuvant therapy; however, their clinicopathological features and prognosis in the era of imatinib are unknown.

Patients and Methods

The study cohort included 665 patients with histologically proven primary GISTs who underwent R0 or R1 surgery between 2003 and 2007; the validation cohort included 182 patients between 2000 and 2014. The definitions of tumor rupture in the study included perforation at tumor site, tumor fracture, piecemeal resection including open biopsy, and macroscopic injuries to the pseudocapsule.

Results

Tumor rupture occurred in 21 (3.2%) of 665 and 5 (2.9%) of 182 patients in the study and validation cohort, respectively. Ruptured GISTs were more symptomatic, were larger in size, and had higher mitotic count than nonruptured GISTs but were not associated with tumor location or laparoscopic surgery. GISTs with intraoperative rupture had clinicopathological features and prognostic outcomes similar to those with preoperative rupture. Recurrence rates were higher and median recurrence-free survival (RFS) and overall survival (OS) were shorter with ruptured than nonruptured GIST. Tumor rupture was one of the independent prognostic factors for RFS, but not OS, according to multivariate analysis.

Conclusions

Ruptured GISTs were symptomatic larger tumors with high mitotic activity, frequent relapse, and shorter RFS. Tumor rupture was an independent prognostic factor for RFS, but not for OS, in the era of imatinib.

Electronic supplementary material

The online version of this article (10.1245/s10434-018-6505-7) contains supplementary material, which is available to authorized users.

Non-exposed endoscopic wall-inversion surgery for gastrointestinal stromal tumor

Laparoscopic and endoscopic cooperative surgery (LECS) is an accepted method of laparoscopic wedge resection, which is minimally invasive, for gastrointestinal stromal tumors (GISTs). We established a type of LECS achieving a full-thickness resection, non-exposed endoscopic wall-inversion surgery (NEWS), in an effort to prevent exposure of the peritoneal cavity to gastric intraluminal contents. We employed this surgical technique in 28 gastric GIST patients. We failed to complete NEWS in the initial two patients and in one patient with a large tumor (40 mm × 35 mm), but otherwise carried out the procedure successfully. Although a learning effect is speculated to occur, based on a decreasing trend in the operation time, the median operation time was 184 minutes showing that NEWS is still a time-consuming method. No significant differences were recognized in tumor size or location, except near the esophagogastric junction (EGJ), nor in the cross-sectional circumference. NEWS is feasible and appears to be a good option, especially for small GISTs with mucosal ulceration rendering full-thickness enucleation by opening of the gastric wall unfeasible.

Retrospective analysis of 85 cases of intermediate-risk gastrointestinal stromal tumor

Background & Aims

A significant benefit of imatinib adjuvant therapy for patients with high risk gastrointestinal stromal tumors (GIST) has been confirmed. However, the effect of imatinib adjuvant therapy for intermediate-risk GIST has not been well studied. In this article, we compare differences of recurrence-free survival (RFS) rates between patients with intermediate-risk GIST who accepted imatinib adjuvant therapy and those who did not.

Method

A retrospective study of intermediate-risk GIST was conducted in the First Affiliated Hospital of Zhengzhou University, China. The pathology reports of 112 patients who had been treated by surgery showed intermediate-risk GIST. The treatment and control groups were designed according to the administration of imatinib adjuvant therapy (≥1 year). Survival and recurrence data were collected and RFS of each group was calculated.

Results

Eighty fivepatients with intermediate-risk GIST were followed up. Thirty of them (treatment group) accepted imatinib adjuvant therapy over 1 year. Through comparing the RFS of the two groups, we established that there was no statistically significant difference in RFS rates (P=0.940).

Conclusion

There is no significant benefit for patients with intermediate-risk GIST to accept imatinib adjuvant treatment.

Recurrence-Free Survival After Resection of Gastric Gastrointestinal Stromal Tumors Classified According to a Strict Definition of Tumor Rupture: A Population-Based Study

BACKGROUND

In gastrointestinal stromal tumors (GISTs), rupture is a high-risk feature and an indication for adjuvant treatment; however, the independent impact of rupture on prognosis is uncertain and the term is inconsistently defined. In the present study, a previously proposed definition of 'tumor rupture' was applied on a population-based cohort of gastric GISTs.

METHODS

Patients undergoing surgery for non-metastatic gastric GISTs from 2000 to 2015 were identified in the regional sarcoma database of Oslo University Hospital. Tumor rupture included spillage or fracture, piecemeal resection, incisional biopsy, blood-tinged ascites, gastric perforation, and microscopic adjacent infiltration. Minor defects of tumor integrity were not considered rupture, i.e. core needle biopsy, peritoneal tumor penetration, superficial peritoneal rupture, and R1 resection. Risk was assessed according to the modified National Institutes of Health consensus criteria.

RESULTS

Among 242 patients, tumor rupture occurred in 22 patients and minor defects of tumor integrity occurred in 81 patients. Five-year recurrence-free survival (RFS) for patients with tumor rupture, minor defects of tumor integrity, and no defect was 37, 91, and 96%, respectively (p < 0.001). In the high-risk group, 5 year RFS for patients with rupture was 37%, versus 77% without rupture (hazard ratio 3.56, 95% confidence interval 1.57-8.08, p = 0.001). On multivariable analysis, tumor rupture and mitotic index were independently associated with recurrence. Of 13 patients who received adjuvant imatinib after tumor rupture, 11 relapsed.

CONCLUSIONS

Tumor rupture according to the present definition was independently associated with recurrence. With tumor rupture, patients relapsed despite adjuvant treatment. Without rupture, prognosis was good, even in the high-risk group.

Management of rectal gastrointestinal stromal tumor

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm of the gastrointestinal tract. However, rectal GIST is rare, the incident rate of it is approximately 5% of all GISTs. Rectal GIST symptoms generally include bleeding and/or pain and occasionally, urinary symptoms. Immunohistochemical evaluation finds that most rectal GIST tumors are CD117 (KIT) positive, and are sometimes CD34, platelet-derived growth factor receptor alpha (PDGFRA), smooth muscle actin, S-100, or vimentin positive. The National Institutes of Health (NIH) classifies rectal GIST as very-low risk, low risk, intermediate risk, or high risk, and the frequencies have been estimated as 0-23.8% for very-low risk, 0-45% for low risk, 0-34% for intermediate risk, and 21-100% for high risk tumors. The first-line treatment for localized GIST is curative resection, but is difficult in rectal GIST because of anatomical characteristics such as the deep, narrow pelvis and proximity to the sphincter muscle or other organs. Several studies noted the efficacy of the minimally invasive surgery, such as trans-anal, trans-sacral, trans-vaginal resection, or laparoscopic resection. The appropriate surgical procedure should be selected depending on the case. Imatinib mesylate (IM) is indicated as first-line treatment of metastatic or unresectable GIST, and clinical outcomes are correlated with KIT mutation genotype. However, the KIT mutation genotypes in rectal GIST are not well known. In this review, as in other GISTs, a large proportion (59-100%) of rectal GISTs carry exon 11 mutations. Although curative resection is indicated for localized rectal GIST, a high rate of local recurrence is a problem. Multimodal therapy including perioperative IM may improve postoperative outcomes, contributing to anus-preserving surgery. Moreover, KIT mutation analysis before IM treatment is important. This review summarizes current treatment strategies for rectal GIST.

Prognostic factors of primary gastrointestinal stromal tumors: a cohort study based on high-volume centers

Objective

We aimed to evaluate the clinicopathologic characteristics, immunohistochemical expression and prognostic factors of patients with primary gastrointestinal stromal tumors (GISTs).

Methods

Data from 2,570 consecutive GIST patients from four medical centers in China (January 2001-December 2015) were reviewed. Survival curves were constructed by the Kaplan-Meier method, and Cox regression models were used to identify independent prognostic factors.

Results

Of the included patients, 1,375 (53.5%) were male, and the patient age range was 18 to 95 (median, 58) years. The tumors were mostly found in the stomach (64.5%), small intestine (25.1%) and colorectal region (5.1%). At the time of diagnosis, the median tumor size was 4.0 (range: 0.1-55.0) cm, and the median mitotic index per 50 high power fields (HPFs) was 3 (range: 0-254). Of the 2,168 resected patients, 2,009 (92.7%) received curative resection. According to the modified National Institutes of Health (NIH) classification, 21.9%, 28.9%, 14.1% and 35.1% were very low-, low-, intermediate- and high-risk tumors, respectively. The rate of positivity was 96.4% for c-Kit, 87.1% for CD34, 96.9% for delay of germination 1 (DOG-1), 8.0% for S-100, 31.0% for smooth muscle actin (SMA) and 5.1% for desmin. However, the prognostic value of each was limited. Multivariate analysis showed that age, tumor size, mitotic index, tumor site, occurrence of curative resection and postoperative imatinib were independent prognostic factors. Furthermore, we found that high-risk patients benefited significantly from postoperative imatinib (P<0.001), whereas intermediate-risk patients did not (P=0.954).

Conclusions

Age, tumor size, mitotic index, tumor site, occurrence of curative resection and postoperative imatinib were independent prognostic factors in patients with GISTs. Moreover, determining whether intermediate-risk patients can benefit from adjuvant imatinib would be of considerable interest in future studies.

Comparison of short- and long-term outcomes of laparoscopic vs open resection for gastric gastrointestinal stromal tumors

AIM

To compare the short- and long-term outcomes of laparoscopic (LR) vs open resection (OR) for gastric gastrointestinal stromal tumors (gGISTs).

METHODS

In total, 301 consecutive patients undergoing LR or OR for pathologically confirmed gGISTs from 2005 to 2014 were enrolled in this retrospective study. After exclusion of 77 patients, 224 eligible patients were enrolled (122 undergoing LR and 102 undergoing OR). The demographic, clinicopathologic, and survival data of all patients were collected. The intraoperative, postoperative, and long-term oncologic outcomes were compared between the LR and OR groups following the propensity score matching to balance the measured covariates between the two groups.

RESULTS

After 1:1 propensity score matching for the set of covariates including age, sex, body mass index, American Society of Anesthesiology score, tumor location, tumor size, surgical procedures, mitotic count, and risk stratification, 80 patients in each group were included in the final analysis. The baseline parameters of the two groups were comparable after matching. The LR group was significantly superior to the OR group with respect to the operative time, intraoperative blood loss, postoperative first flatus, time to oral intake, and postoperative hospital stay (P < 0.05). No differences in perioperative blood transfusion or the incidence of postoperative complications were observed between the two groups (P > 0.05). No significant difference was found in postoperative adjuvant therapy (P = 0.587). The mean follow-up time was 35.30 ± 26.02 (range, 4-102) mo in the LR group and 40.99 ± 25.07 (range, 4-122) mo in the OR group with no significant difference (P = 0.161). Survival analysis showed no significant difference in the disease-free survival time or overall survival time between the two groups (P > 0.05).

CONCLUSION

Laparoscopic surgery for gGISTs is superior to open surgery with respect to intraoperative parameters and postoperative outcomes without compromising long-term oncological outcomes.

Gastrointestinal stromal tumour (GIST) presenting as a strangulated inguinal hernia with small bowel obstruction

Gastrointestinal stromal tumours (GISTs) can arise everywhere along the gastrointestinal (GI) tract. Their presentation in unusual locations should always be taken into account. A 74-year-old man referred to the emergency department for small bowel obstruction caused by an incarcerated inguinal hernia. A CT scan showed a mesenchymal tumour originating from the herniated bowel loop and a mass in the ascending colon. Laparoscopic resection of the mass and laparoscopic right hemicolectomy were performed. The histology showed a ruptured GIST arising from the herniated small bowel and a high-grade dysplasia villous adenoma of the right colon. GISTs can present with symptoms spanning from vague abdominal discomfort to surgical urgencies. Strangulated hernia is an extremely rare presentation, with only two cases described in the literature. A safe surgical approach was obtained with laparoscopy, maintaining surgical radicality. The ileal localisation and the pseudocapsule rupture were the main risk factors on prognostic stratification.

Computed tomography features and predictive findings of ruptured gastrointestinal stromal tumours

OBJECTIVES

To evaluate the CT features of ruptured GISTs and factors that might be predictive of rupture through comparison with CTs taken prior to rupture and CTs of non-ruptured GIST.

METHODS

Forty-nine patients with ruptured GIST and forty-nine patients with non-ruptured GIST matched by age, gender and location were included. Clinical data including pharmacotherapy were reviewed. The imaging features were analyzed. Prior CT obtained before rupture were evaluated.

RESULTS

The most common location of ruptured GIST was small bowel with mean size of 12.1 cm. Ruptured GIST commonly showed wall defects, >40 % eccentric necrosis, lobulated shaped, air density in mass, pneumoperitoneum, peritonitis, hemoperitoneum and ascites (p < 0.001-0.030). Twenty-seven of 30 patients with follow up imaging received targeted therapy. During follow-up, thickness of the tumour wall decreased. Increase in size and progression of necrosis were common during targeted therapy (p = 0.017). Newly developed ascites, peritonitis and hemoperitoneum was more common (p < 0.001-0.036).

CONCLUSION

Ruptured GISTs commonly demonstrate large size, >40 % eccentric necrosis, wall defects and lobulated shape. The progression of necrosis with increase in size and decreased wall thickness during targeted therapy may increase the risk of rupture. Rupture should be considered when newly developed peritonitis, hemoperitoneum, or ascites are noted during the follow-up.

KEY POINTS

• Ruptured GISTs demonstrate large size, eccentric necrosis, wall defects, and lobulated shape. • Rupture should be considered when peritonitis or hemoperitoneum/adjacent hematoma newly appears. • Progression of necrosis with increase in size increases the risk of rupture.

Pediatric/"Wildtype" gastrointestinal stromal tumors

Pediatric/"Wildtype" gastrointestinal stromal tumor (P/WT-GIST) is a rare cancer, distinct and markedly different from the phenotype found predominantly in older patients (adult, non-wildtype GIST). Having a different molecular signature, it is not responsive to standard adjuvant therapies utilized in adult GIST, and surgery remains the only effective cure. However, even with presumed complete resections in patients with localized disease at presentation, recurrence rates are high. Furthermore, it is an indolent cancer that can persist for decades, and treatment strategies must balance the possible morbid risks of intervention with the reality of preserving quality of life in the interim. Effective adjuvant therapies remain elusive, and research is critically needed to identify both targets and drugs for treatment consideration.

Combined Therapy of Gastrointestinal Stromal Tumors

Radical surgery is the mainstay of therapy for primary resectable, localized gastrointestinal stromal tumors (GIST). Nevertheless, approximately 40% to 50% of patients with potentially curative resections develop recurrent or metastatic disease. The introduction of imatinib mesylate has revolutionized the therapy of advanced (inoperable and/or metastatic) GIST and has become the standard of care in treatment of patients with advanced GIST. This article discusses the proper selection of candidates for adjuvant and neoadjuvant treatment in locally advanced GIST, exploring the available evidence behind the combination of preoperative imatinib and surgery.

Comparison of the post-operative outcomes and survival of laparoscopic versus open resections for gastric gastrointestinal stromal tumors: A multi-center prospective cohort study

BACKGROUND AND OBJECTIVES

Laparoscopic resection (LR) is increasingly performed for gastrointestinal stromal tumor (GIST). The aim of this study is to investigate the short-term outcomes and therapeutic effects of LR compared to open resection (OR) of gastric GISTs.

METHODS

During 2009-2014, a prospective cohort of 200 patients with gastric GISTs indicated for resection underwent LR and OR procedures in three centers in Shanghai. Patient demographics, peri-operative complications, and clinical outcomes were compared between the two groups.

RESULTS

After exclusions, 176 patients who underwent gastric GIST resections were compared, of which 91 were laparoscopic, 85 were open. Compared to open surgery, laparoscopic resection of GIST has shorter operative time (102 vs. 172 min, p < 0.001), lower blood loss (100 vs 144 ml, p < 0.001), and shorter length of stay (9.1 vs. 15.3 d, p < 0.001). No statistical significant difference is observed for time to bowel function or semi-liquid diet, complications, recurrence rates, and mortality.

CONCLUSION

LR is a safe and efficacious treatment for gastric GISTs, providing the advantages of shorter operative time, reduced blood loss, and shorter length of stay, all without compromising post-operative outcomes and survival.

Is multivisceral resection in locally advanced gastrointestinal stromal tumours an acceptable strategy?

BACKGROUND

Gastrointestinal stromal tumours (GISTs) represent the most common mesenchymal tumour of the gastrointestinal tract. Although the efficacy of targeted therapy cannot be over-emphasized, surgery remains the only curative primary treatment for patients with localized disease. The median size of GIST at diagnosis is approximately 5-7 cm; however, it is not uncommon for tumours to be as large as 30-40 cm and involving multiple viscera.

METHODS

Data were retrospectively collected from patients with GISTs treated at the Singapore General Hospital and the National Cancer Centre Singapore over a 15-year period. Standard resection of GIST without any additional organ removal was termed as a single organ resection (SOR). If the tumour was adjacent to another organ, necessitating the removal of more than one organ, the procedure was defined as a multivisceral resection (MVR). We aim to evaluate the role of MVR in the management of large GISTs.

RESULTS

A total of 187 patients underwent curative surgery for GIST between January 2000 and January 2014. Of the 187 patients, 40 (21%) underwent MVR whereas 147 (79%) had SOR. Patients in the MVR group had significantly larger tumour sizes (P < 0.001) yet R0 and R1 resection was achieved in all patients, and no intra-peritoneal rupture was reported. On comparison of MVR versus SOR groups, there was no significant difference in in-hospital morbidity and mortality.

CONCLUSION

MVR may be required to achieve negative margins in patients with large GISTs, and can be performed with acceptable morbidity and mortality.

Targeting gastrointestinal stromal tumors: the role of regorafenib

Gastrointestinal stromal tumor (GIST) is a devastating disease in the metastatic setting, but its natural history has been dramatically altered by the development of small molecule tyrosine kinase inhibitors, most notably imatinib. Although patients with advanced GIST live much longer today than they did in the past, imatinib-refractory disease remains a tremendous problem. For disease that is refractory to imatinib and sunitinib, regorafenib is an excellent option. In this review, we discuss the biology and clinical work establishing regorafenib as the standard of care for advanced GIST refractory to both imatinib and sunitinib.

Surgical Treatment of Gastrointestinal Stromal Tumors Located in the Stomach in the Imatinib Era

BACKGROUND

Imatinib has changed the treatment of gastrointestinal stromal tumors (GISTs). Preoperative imatinib treatment can be administered to patients with locally advanced disease to reduce the risk of incomplete resection, tumor spill, and lessen the extent of resection. In metastatic GIST, surgery follows imatinib in responding patients with resectable disease. In this study, the outcome of surgically treated patients with a gastric GIST with and without preoperative imatinib was investigated.

METHODS

Patients surgically treated for a gastric GIST at our institute between 1999 and 2011 were included. Patient data were retrieved from a prospectively maintained database.

RESULTS

A consecutive series of 47 patients was identified: 17 patients were treated with primary surgery (group 1) and 30 patients received imatinib before surgery (group 2). Preoperative imatinib led to a 33% reduction in tumor size. All patients in group 1 and 23 patients (77%) in group 2 had a complete resection (R0) without tumor spill. At a median follow-up of 30 months, 4 patients in group 2 had died of GIST. In these 4 patients, either the resection had been irradical or tumor spill had occurred, and 3 of them had radiologic progressive disease at the time of surgery.

CONCLUSIONS

In this surgical series of gastric GIST patients, preoperative imatinib led to a major reduction in tumor size. Irradical resection, tumor spill, and progressive disease at the time of surgery were associated with poor prognosis.

MicroRNAs and Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumor (GIST) is the most commonly diagnosed mesenchymal tumor in the gastrointestinal tract. This tumor type is driven by gain-of-function mutations in receptor tyrosine kinases (such as KIT, PDGFRA, and BRAF) or loss-of-function mutations in succinate dehydrogenase complex subunit genes (SDHx). Molecular studies on GIST have improved our understanding of the biology of the disease and have led to the use of targeted therapy approach, such as imatinib for KIT/PDGFRA-mutated GIST. Recently, microRNAs have emerged as important regulators of KIT expression, cancer cell behavior, and imatinib response in GIST. This chapter aims to provide an overview on current understanding of the biological roles of microRNAs in GIST and possible implications in prognosis and therapeutic response.

Surgical strategy for the gastric gastrointestinal stromal tumors (GISTs) larger than 5 cm: laparoscopic surgery is feasible, safe, and oncologically acceptable

BACKGROUND

The efficacy and feasibility of laparoscopic surgery (LAP) for gastric GISTs >5 cm has not been adequately assessed. Here we investigated the clinical outcomes of these patients.

PATIENTS AND METHODS

Twenty-seven consecutive patients who underwent resection for gastric GISTs >5 cm were enrolled in this retrospective study. We assessed the tumor characteristics, surgical outcomes, tumor recurrence, and patient survival in the open surgery (OPEN) group and in the LAP group.

RESULTS

The tumor size in the OPEN group was larger than that in the LAP group, but there were no differences in the mitotic count. There were no differences in operative complications. Finally, there were no differences in the disease-free and no patients in the LAP group died.

CONCLUSIONS

In patients with gastric GISTs >5 cm, LAP can be performed with outcomes equivalent to those of OPEN if patient selection and intraoperative judgment are appropriate.

Definition and clinical significance of tumour rupture in gastrointestinal stromal tumours of the small intestine

BACKGROUND

Tumour rupture is a risk factor for recurrence of gastrointestinal stromal tumour (GIST). In this study, patterns of recurrence after potential tumour seeding were investigated, and a new definition of tumour rupture, based on major and minor defects of tumour integrity, is proposed.

METHODS

Patients undergoing surgery for non-metastatic small intestinal GIST from 2000 to 2012 were included in the study. Tumour spillage, tumour fracture or piecemeal resection, bowel perforation at the tumour site, blood-tinged ascites, microscopic tumour infiltration into an adjacent organ, and surgical biopsy were defined as major defects of tumour integrity. Peritoneal tumour penetration, iatrogenic peritoneal laceration and microscopically involved margins were defined as minor defects.

RESULTS

Seventy-two patients were identified. Median follow-up was 58 (range 7-122) months. Radical surgery was performed in 71 patients. A major defect was recorded in 20 patients, and a minor defect in 21. The 5-year recurrence rate was 64, 29 and 31 per cent in patients with major, minor and no defect respectively (P = 0·001). The hazard ratio (HR) for major defect versus no defect was 3·55 (95 per cent c.i. 1·51 to 8·35). Peritoneal recurrence rates for major, minor and no defect were 52, 25 and 19 per cent respectively (P = 0·002), and the HR for major defect versus no defect was 4·98 (1·69 to 14·68). On multivariable analysis, mitotic index, major defect of tumour integrity, tumour size and age were independently associated with risk of recurrence.

CONCLUSION

Recurrence rates were increased after major, but not minor tumour ruptures.

From esophagus to rectum: a comprehensive review of alimentary tract perforations at computed tomography

Gastrointestinal (GI) tract perforation is a life-threatening condition that can occur at any site along the alimentary tract. Early perforation detection and intervention significantly improves patient outcome. With a high sensitivity for pneumoperitoneum, computed tomography (CT) is widely accepted as the diagnostic modality of choice when a perforated hollow viscus is suspected. While confirming the presence of a perforation is critical, clinical management and surgical technique also depend on localizing the perforation site. CT is accurate in detecting the site of perforation, with segmental bowel wall thickening, focal bowel wall defect, or bubbles of extraluminal gas concentrated in close proximity to the bowel wall shown to be the most specific findings. In this article, we will present the causes for perforation at each site throughout the GI tract and review the patterns that can lead to prospective diagnosis and perforation site localization utilizing CT images of surgically proven cases.

Oncologic Safety of Laparoscopic Wedge Resection with Gastrotomy for Gastric Gastrointestinal Stromal Tumor: Comparison with Conventional Laparoscopic Wedge Resection

Purpose

Various laparoscopic wedge resection (LWR) techniques requiring gastrotomy for gastrointestinal stromal tumors (GISTs) of the stomach have been applied to facilitate tumor resection and preserve the remnant gastric volume. However, there is the possibility of cancer cell dissemination during these procedures. The aim of this study was to assess the oncologic safety of LWR with gastrotomy (LWR-G) compared to LWR without luminal exposure.

Materials and Methods

Clinicopathologic and operative results of 193 patients who underwent LWR for gastric GIST were retrospectively analyzed from 2003 to 2013. We stratified the patients into two groups: LWR-G and LWR without gastrotomy (LWR-C). Clinicopathologic features, short-term outcomes, and long-term outcomes were compared.

Results

A total of 26 patients underwent LWR-G, and 167 patients underwent LWR-C. The LWR-G group showed significantly more anterior wall-located (n=10, 38.5%), intraluminal (n=20, 76.9%), and ulcerative (n=13, 50.0%) tumors than the LWR-C group (n=33, 19.8%; n=96, 57.5%; n=46, 27.5%, respectively). Postoperative short-term outcomes did not differ between the two groups. When tumor staging was compared, no statistical difference was noted. There was no recurrence in the LWR-G group, while 2 patients in the LWR-C group experienced recurrence. The two recurrences in the LWR-C group were found in the liver and in the remnant stomach at 63 and 12 months after the operation, respectively. No gastric GIST-related death was recorded in any group during the study period.

Conclusions

LWR-G for gastric GIST is an oncologically safe procedure even for masses with ulcerations.

C-Kit-Negative Gastrointestinal Stromal Tumor in the Stomach

C-kit-negative gastrointestinal stromal tumors (GISTs) are uncommon, and there have been few reports about the diagnosis and treatment of c-kit-negative GISTs in the stomach. We report the case of a patient who was diagnosed with a huge and atypical GIST in the stomach. The GIST was completely resected and finally diagnosed as c-kit-negative GIST based on immunohistochemical staining of tumor cells, which were negative for CD117 and CD34 and positive for Discovered on GIST-1 (DOG1). C-kit-negative GISTs could be treated by complete resection and/or imatinib, which is the same treatment for c-kit-positive GISTs.

Time to Definitive Failure to the First Tyrosine Kinase Inhibitor in Localized GI Stromal Tumors Treated With Imatinib As an Adjuvant: A European Organisation for Research and Treatment of Cancer Soft Tissue and Bone Sarcoma Group Intergroup Randomized Trial in Collaboration With the Australasian Gastro-Intestinal Trials Group, UNICANCER, French Sarcoma Group, Italian Sarcoma Group, and Spanish Group for Research on Sarcomas

PURPOSE

In 2004, we started an intergroup randomized trial of adjuvant imatinib versus no further therapy after R0-R1 surgery patients with localized, high- or intermediate-risk GI stromal tumor (GIST).

PATIENTS AND METHODS

Patients were randomly assigned to 2 years of imatinib 400 mg daily or no further therapy after surgery. The primary end point was overall survival; relapse-free survival (RFS), relapse-free interval, and toxicity were secondary end points. In 2009, given the concurrent improvement in prognosis of patients with advanced GIST, we changed the primary end point to imatinib failure-free survival (IFFS), with agreement of the independent data monitoring committee. We report on a planned interim analysis.

RESULTS

A total of 908 patients were randomly assigned between December 2004 and October 2008: 454 to imatinib and 454 to observation. Of these, 835 patients were eligible. With a median follow-up of 4.7 years, 5-year IFFS was 87% in the imatinib arm versus 84% in the control arm (hazard ratio, 0.79; 98.5% CI, 0.50 to 1.25; P = .21); RFS was 84% versus 66% at 3 years and 69% versus 63% at 5 years (log-rank P < .001); and 5-year overall survival was 100% versus 99%, respectively. Among 528 patients with high-risk GIST by local pathologist, 5-year IFFS was 79% versus 73%; among 336 centrally reviewed high-risk patients, it was 77% versus 73%, respectively.

CONCLUSION

This study confirms that adjuvant imatinib has an overt impact on RFS. No significant difference in IFFS was observed, although in the high-risk subgroup there was a trend in favor of the adjuvant arm. IFFS was conceived as a potential end point in the adjuvant setting because it is sensitive to secondary resistance, which is the main adverse prognostic factor in patients with advanced GIST.

Long-Term Surgical Outcome of 1057 Gastric GISTs According to 7th UICC/AJCC TNM System: Multicenter Observational Study From Korea and Japan

The aim of this study was to evaluate the treatment and prognosis of gastric gastrointestinal stromal tumors (GISTs) according to the 7th UICC/AJCC tumor-node-metastasis (TNM) system and the modified National Institutes of Health (NIH) risk classification. The study cohort consisted of 1057 patients with gastric GIST who underwent surgery between January 2000 and December 2007 from 13 institutions in Korea and 2 in Japan. Clinicopathologic characteristics, surgical outcomes, recurrence, and 5-year recurrence-free survival were evaluated.The mean age of the patients was 58.6 years. Thirty patients (2.8%) had distant metastasis preoperatively. Median tumor size was 4.0 cm. Complete resection (R0 resection) was achieved in 1018 patients (96.3%). Eighty-six patients (8.1%) had postoperative complications, and 2 patients (0.2%) died within 30 days after surgery. According to the 7th UICC/AJCC TNM system, 5-year recurrence-free survival rates were 95% to 99% in stage I, 94.1% in stage II, 74.1% in stage IIIA, 48.6% in stage IIIB, and 50.0% in stage IV patients. On survival analysis of high-risk patients according to the TNM system, the 5-year recurrence-free survival rates were 91.6% in stage II, 74.1% in stage IIIA, and 48.6% in stage IIIB patients. Independent factors of recurrence following surgery for gastric GIST were gender, tumor size, mitotic count, and radicality on multivariate analysis.The treatment outcome and prognosis of gastric GIST in Korea and Japan seem more favorable compared to those in Western countries. Compared to the modified NIH risk classification, the 7th UICC/AJCC TNM system is more reflective of the 5-year recurrence-free survival of patients with gastric GIST.

Surgery for gastrointestinal stromal tumors (GISTs) of the stomach and small bowel: short- and long-term outcomes over three decades

BACKGROUND

Many studies on gastrointestinal stromal tumors (GISTs) derive from tertiary referral centers, but few examine strictly population-based cohorts. Thus, we evaluated the clinical features, surgical treatments, clinical outcomes, and factors predicting the survival of patients with GISTs in a population-based series.

METHODS

Patients with GISTs diagnosed at Stavanger University Hospital over three decades (1980-2012) were analyzed. Data were retrieved from hospital records. Descriptive statistics and survival analyses (Kaplan-Meier) are presented. A limited number of colorectal GISTs (n = 6) restricted most analyses to those with a gastric or small bowel location.

RESULTS

Among 66 patients surgically treated for GISTs, 60 patients (91 %) had either a gastric or a small bowel localization. Females comprised 61 %. The median age at diagnosis was 63 (range, 15-88) years. Clinical symptoms were recorded in 43 patients (65 %). Complete tumor resection was achieved in 85 % of the patients. During follow-up, 6 patients were surgically treated for local recurrence or metastatic disease. The median follow-up time was 6.1 years. At last follow-up, 30 patients (46 %) were deceased, 10 of whom died from GISTs. The median overall survival was 10.4 years. For GISTs with a gastric or small bowel location, a 1- and 5-year disease-specific survival of 100 and 96 %, and a relapse-free survival of 96 and 78 % were observed. Male gender, incidental diagnosis, smaller tumor size, a low mitotic rate, an intact pseudocapsule, low-risk categorization, and an early stage were significantly associated with improved outcomes.

CONCLUSION

Surgery in a low-volume, population-based setting yields enhanced long-term disease and recurrence-free survival for patients with GISTs of the stomach or small bowel. Incidental diagnosis, complete tumor resection, and low-risk categorization are good predictors of long-term prognosis.

MDCT and clinicopathological features of small bowel gastrointestinal stromal tumours in 102 patients: a single institute experience

OBJECTIVE

Small bowel (SB) is the second most common site of gastrointestinal stromal tumours (GISTs). We evaluated clinical presentation, pathology, imaging features and metastatic pattern of SB GIST.

METHODS

Imaging and clinicopathological data of 102 patients with jejunal/ileal GIST treated at Dana-Farber Cancer Institute and Brigham and Women's Hospital (Boston, MA) between 2002 and 2013 were evaluated. Imaging of treatment-naive primary tumour (41 patients) and follow-up imaging in all patients was reviewed.

RESULTS

90/102 patients were symptomatic at presentation, abdominal pain and lower gastrointestinal blood loss being the most common symptoms. On pathology, 21 GISTs were low risk, 17 were intermediate and 64 were high risk. The mean tumour size was 8.5 cm. On baseline CT (n = 41), tumours were predominantly well circumscribed, exophytic and smooth/mildly lobulated in contour. Of 41 tumours, 16 (39%) were homogeneous, whereas 25 (61%) were heterogeneous. Of the 41 tumours, cystic/necrotic areas (Hounsfield units < 20) were seen in 16 (39%) and calcifications in 9 (22%). CT demonstrated complications in 13/41 (32%) patients in the form of tumour-bowel fistula (TBF) (7/41), bowel obstruction (4/41) and intraperitoneal rupture (2/41). Amongst 102 total patients, metastases developed in 51 (50%) patients (27 at presentation), predominantly involving peritoneum (40/102) and liver (32/102). 7/8 (87%) patients having intraperitoneal rupture at presentation developed metastases. Metastases elsewhere were always associated with hepatic/peritoneal metastases. At last follow-up, 28 patients were deceased (median survival, 65 months).

CONCLUSION

SB GISTs were predominantly large, well-circumscribed, exophytic tumours with or without cystic/necrotic areas. Complications such as TBF, bowel obstruction and intraperitoneal perforation were visualized at presentation, with patients with perforation demonstrating a high risk of metastatic disease. Exophytic eccentric bowel wall involvement and lack of associated adenopathy are useful indicators to help differentiate GISTs from other SB neoplasms.

ADVANCES IN KNOWLEDGE

SB GISTs are predominantly large, well-circumscribed, exophytic tumours, and may present with complications. They often are symptomatic at presentation, are high risk on pathology and metastasize to the peritoneum more commonly than the liver.

A Case of Disseminated Intra-abdominal Gastrointestinal Stromal Tumor Managed with Low Dose Imatinib

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. Imatinib mesylate is recommended as adjuvant therapy for GIST after surgical resection. However, drug-related adverse events are common. A 74-year-old female with metastatic GIST who was managed with imatinib experienced severe adverse events, including skin rashes, tremor, and alopecia, etc. The imatinib dose was reduced and the size of the metastatic GIST continued to decrease and adverse events showed significant improvement.

Adherence to Guidelines for Adjuvant Imatinib Therapy for GIST: A Multi-institutional Analysis

BACKGROUND

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. Adjuvant imatinib therapy improves recurrence-free and overall survival following surgery for patients with high-risk GIST; however, the factors associated with use of adjuvant imatinib therapy are unclear, and adherence to adjuvant imatinib has not been investigated. We sought to determine the clinicopathologic predictors of therapy with adjuvant imatinib following surgical resection for GIST and to determine the utilization of adjuvant imatinib in patients who underwent surgical resection of primary GIST in 2009 or later as recommended by National Comprehensive Cancer network (NCCN) guidelines.

METHODS

A multi-institutional cohort including 171 patients who underwent surgery for primary GIST at seven high-volume cancer centers in the USA and Canada between January 2009-December 2012 was used in this study. Receipt of adjuvant imatinib therapy was ascertained, and factors associated with imatinib therapy were analyzed.

RESULTS

Following surgery for primary GIST, tumor size (<5.0 cm: ref; 5.0-9.9 cm: odds ratio (OR) 2.36, 95 % confidence interval (CI) 0.74-7.55; >10.0 cm: OR 9.15, 95 % CI 2.28-36.75; p = 0.007), mitotic rate (≤5/50 mitoses per 50 high powered field [HPF]: ref; 6-10/50 HPF: OR 24.91, 95 % CI 3.64-170.35; >10/50 HPF: OR 5.80, 95 % CI 3.64-170.35; p < 0.001), and neoadjuvant therapy (OR 9.52; 95 % CI 2.51-36.14; p = 0.001) were associated with receipt of adjuvant imatinib therapy. Overall, 75 % of patients received appropriate treatment, 23 % of patients were undertreated, and 2 % of patients were overtreated as compared to NCCN guidelines. Adjuvant imatinib therapy was administered in only 53 % of patients for which the NCCN guidelines recommended adjuvant therapy.

CONCLUSION

The clinicopathologic factors associated with use of adjuvant imatinib therapy in patients following resection of primary GIST are consistent with established risk factors for recurrence. Adjuvant imatinib therapy remains underutilized in patients with intermediate and high-risk GIST and in patients who receive neoadjuvant therapy. Barriers to adjuvant imatinib therapy in this group of patients needs to be further explored.

Prognostic characteristics of duodenal gastrointestinal stromal tumours

Background

This study evaluated the clinical characteristics, surgical procedures and prognosis of duodenal gastrointestinal stromal tumours (GISTs).

Methods

Patients with a diagnosis of primary duodenal GIST treated between January 2000 and December 2012 were analysed. Patients with gastric and small intestinal GISTs were chosen as control groups according to the following parameters: age, tumour size, mitotic index and adjuvant imatinib therapy. Operative procedures for patients with duodenal GIST included pancreaticoduodenectomy or limited resection. Disease-free survival (DFS) was calculated using Kaplan–Meier analysis.

Results

Some 71 patients with duodenal, 71 with gastric and 70 with small intestinal GISTs were included in the study. DFS of patients with duodenal GIST was shorter than that of patients with gastric GIST (3-year DFS 84 versus 94 per cent; hazard ratio (HR) 3.67, 95 per cent c.i. 1.21 to 11.16; P = 0.014), but was similar to that of patients with small intestinal GIST (3-year DFS 84 versus 81 per cent; HR 0.75, 0.37 to 1.51; P = 0.491). Patients who underwent pancreaticoduodenectomy were older, and had larger tumours and a higher mitotic index than patients who had limited resection. The 3-year DFS was 93 per cent among patients who had limited resection compared with 64 per cent for those who underwent PD (HR 0.18, 0.06 to 0.59; P = 0.001).

Conclusion

The prognosis of duodenal GISTs is similar to that of small intestinal GISTs.

Prognosis no different than for small bowel gastrointestinal stromal tumours

[Spectrum of laparoscopic surgery for gastric tumors]

Minimally invasive operative procedures are increasingly being used for treating tumors of the upper gastrointestinal tract. While minimally invasive surgery (MIS) has become established as a standard procedure for benign tumors and gastrointestinal stromal tumors (GIST) based on current studies, the significance of MIS in the field of gastric cancer is the topic of heated debate. Until now the majority of studies and meta-analyses on gastric cancer have come from Asia and these indicate the advantages of MIS in terms of intraoperative blood loss, minor surgical complications and swifter convalescence although without any benefits in terms of long-term oncological results and quality of life. Unlike in Germany, gastric cancer in Asia with its unchanged high incidence rate, 50 % frequency of early carcinoma and predominantly distal tumor localization is treated at high-volume centres. Due to the proven marginal advantages of MIS over open resection described in the published studies no general recommendation for laparoscopic surgery of gastric cancer can currently be given.

Two cases of advanced gastric carcinoma mimicking a malignant gastrointestinal stromal tumor

Gastric cancer that mimics a submucosal tumor is rare. This rarity and the normal mucosa covering the protuberant tumor make it difficult to diagnosis with endoscopy. We report two cases of advanced gastric cancer that mimicked malignant gastrointestinal stromal tumors preoperatively. In both cases, the possibility of cancer was not completely ruled out. In the first case, a large tumor was suspected to be cancerous during surgery. Therefore, total gastrectomy with lymph node dissection was performed. In the second case, the first gross endoscopic finding was of a Borrmann type II advanced gastric cancer-like protruding mass with two ulcerous lesions invading the anterior wall of the body. Therefore, subtotal gastrectomy with lymph node dissection was performed. Consequently, delayed treatment of cancer was avoided in both cases. If differential diagnosis between malignant gastrointestinal stromal tumor and cancer is uncertain, a surgical approach should be carefully considered due to the possible risk of adenocarcinoma.

Re-appraisal of risk classifications for primary gastrointestinal stromal tumors (GISTs) after complete resection: indications for adjuvant therapy

BACKGROUND

A substantial number of localized gastrointestinal stromal tumor (GIST) patients have recurrences even after complete resection. The risk of recurrence after complete resection should be estimated when considering adjuvant therapy. In this study, we evaluated prognostic factors of GIST recurrence and compared several reported risk-stratification schemes for defining risk of recurrence to guide the use of adjuvant therapy using data from a large Japanese GIST population.

METHODS

We analyzed clinicopathological data collected retrospectively and prospectively from 712 GISTs with complete resection from 1980-2010. We evaluated possible prognostic factors and compared the National Institutes of Health consensus criteria, the Armed Forces Institute of Pathology criteria, Joensuu's modified NIH classification (J-NIHC), the American Joint Committee on Cancer staging system (AJCCS), and the Japanese modified NIH criteria for prediction of tumor recurrence in adjuvant settings.

RESULTS

Univariate analysis suggested that the following factors were prognostic: tumor size, mitotic count, site, clinically malignant features of rupture and/or invasion, and gender. In multivariate analysis, size >5 cm, mitotic count >5/50 HPF, non-gastric location, and the presence of rupture and/or macroscopic invasion were independent adverse prognostic factors. When adjuvant therapy is considered for patients with high-risk GIST, the J-NIHC was the most sensitive classification system, while the AJCCS appeared to be the most accurate for predicting recurrence.

CONCLUSION

Tumor size, mitotic count, tumor site, and clinical features of rupture and/or invasion were important prognostic factors for GIST recurrence. Joensuu's classification appeared to best identify candidates for adjuvant therapy.

BWH emergency radiology--surgical correlation: small-bowel GI stromal tumor perforation

We present the radiological and intraoperative correlation of a large necrotic gastrointestinal stromal tumor (GIST) with features of a tumor-bowel fistula and perforation in a 49-year-old woman presenting to the emergency department with a 4-day history of worsening abdominal pain, vomiting, and diarrhea. The patient underwent urgent exploratory laparotomy for partial resection of the small bowel, with primary anastomosis. The purpose of this article is to emphasize the importance for emergency radiologists to be familiar with this entity and its possible complications to help guide the surgeons in the patient's management.

A Systematic Review and Meta-Analysis of Open vs. Laparoscopic Resection of Gastric Gastrointestinal Stromal Tumors

Gastric gastrointestinal stromal tumors (GISTs) are the most common sarcoma of the gastrointestinal tract, and surgical resection is the primary treatment of early disease. Limited data exist concerning laparoscopic resections of these neoplasms. This systematic review was designed to evaluate the literature comparing laparoscopic and open surgical resection of gastric GISTs and to assess the effectiveness and safety of this minimally invasive technique. We performed a systematic search of MEDLINE, the Cochrane Library, PubMed, Embase, Scopus, Web of Science, Google Scholar, the clinical trials database and ProQuest Dissertations and Theses as well as the past 3 years of conference abstracts from the Society of American Gastrointestinal and Endoscopic Surgeons Annual Meetings. Studies comparing the open and the laparoscopic approaches to the resection of gastric GISTs were included in this systematic review. Two reviewers independently performed the screen of titles and abstracts, the full manuscript review, the data extraction and the risk of bias assessment. A quantitative analysis was performed. Of the 189 studies identified, seven studies were included. The laparoscopic approach was associated with a significantly lower length of hospital stay (3.82 days (2.14 - 5.49)). There was no observed difference in operative time, adverse events, estimated blood loss, overall survival and recurrence rates. This study supports that laparoscopic resection is safe and effective for gastric GISTs and is associated with a significantly lower length of hospital stay. Further trials are needed for cost analysis and to rigorously assess oncologic outcomes.

Cyclin-Dependent Kinase Activity Correlates with the Prognosis of Patients Who Have Gastrointestinal Stromal Tumors

BACKGROUND

The estimation of recurrence risk remains a critical issue in relation to gastrointestinal stromal tumors (GISTs) treated with adjuvant therapy. The accuracy of the commonly used risk stratifications is not always adequate.

METHODS

For this study, data were prospectively collected from 68 patients with GISTs who underwent R0 surgery between 2004 and 2009. The results from this analysis cohort were evaluated using the data obtained from an additional 40 patients in the validation cohort. Cyclin-dependent kinase 1 (CDK1)- and CDK2-specific activities were measured using a non-RI kinase assay system.

RESULTS

The specific activities of CDK1 and CDK2, but not their expression, significantly correlated with recurrence. The specific activities of both CDK1 and CDK2 were independently correlated with mitosis and significantly correlated with recurrence-free survival (RFS). In the multivariate analysis, CDK2-specific activity (P = 0.0006), tumor size (P = 0.0347), and KIT deletion mutations (P = 0.0006) were significantly correlated with RFS in the analysis cohort. In the validation cohort, CDK2-specific activity (P = 0.0368) was identified as an independent prognostic factor for tumor recurrences with tumor location (P = 0.0442).

CONCLUSION

The results suggest that the specific activities of CDK1 and CDK2 may reflect the proliferative activity of GISTs and that CDK2-specific activity is a good prognostic factor predicting recurrence after macroscopic complete resection of GISTs.

Sphincter sparing resection of a large obstructive distal rectal gastrointestinal stromal tumour after neoadjuvant therapy with imatinib (Glivec)

Gastrointestinal stromal tumours (GISTs) are generally rare but are known to be the most common mesenchymal tumours of the gastrointestinal tract. We present a case of a patient who presented with persistent obstructive gastrointestinal and urological symptoms, a sense of incomplete evacuation and bleeding per rectum. A colonoscopy was performed and a biopsy was taken of a submucosal mass in the distal rectum that revealed a GIST with positive KIT immunostaining. A positron emission tomography (PET)/CT scan showed a large metabolically active distal rectal tumour of 8 cm with macroscopic invasion of surrounding structures. Neoadjuvant therapy with receptor tyrosine kinase inhibitor imatinib (400 mg orally daily) was initiated and an excellent partial response consisting of a significant decrease in the size of the tumour with complete metabolic resolution was observed within 3 months. Six months after initiation of the neoadjuvant therapy a rectum resection with manual side-to-end coloanal anastomosis was performed. Pathology showed a GIST of 5 cm located 0.1 cm from the distal section plane. Our case shows that in patients with a large invasive distal rectal GIST, neoadjuvant imatinib therapy can facilitate anal sphincter sparing surgery.

A nomogram to predict disease-free survival after surgical resection of GIST

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Adjuvant imatinib therapy has resulted in improved disease-free survival (DFS) following resection of primary GIST. The aim of our study was to create a nomogram to predict DFS following resection of GIST.

METHOD

Using a multi-institutional cohort of patients who underwent surgery for primary GIST at 7 academic hospitals in the USA and Canada between January 1998 and December 2012, a multivariable Cox proportional hazards model predicting DFS was created using backward stepwise selection. A nomogram to predict DFS following surgical resection of GIST was constructed with the variables selected in the multivariable model. We tested nomogram discrimination by calculating the C-statistic and compared the nomogram to four existing GIST prognostic stratification systems.

RESULTS

A total of 365 patients who underwent surgery for primary GIST was included in the study. Using backward stepwise selection, sex, tumor size, tumor site, and mitotic rate were selected for incorporation into the nomogram. The nomogram demonstrated superior discrimination compared to the NIH criteria, modified NIH criteria, and Memorial Sloan-Kettering Nomogram and had similar discrimination to the Miettinen criteria (C-statistic 0.77 vs 0.73, 0.71, 0.71, and 0.78, respectively).

CONCLUSION

Four independent predictors of recurrence following surgery for primary GIST were used to create a nomogram to predict DFS. The nomogram stratified patients into prognostic groups and performed well on internal validation.

Surgical management of advanced gastrointestinal stromal tumors: an international multi-institutional analysis of 158 patients

BACKGROUND

Patients with advanced gastrointestinal stromal tumors (GIST) are at high risk for recurrence after surgery. The aim of this study was to characterize outcomes of advanced GIST treated with surgery from a large multi-institutional database in the tyrosine kinase inhibitor (TKI) era.

STUDY DESIGN

Patients who underwent surgery for an advanced GIST from 1998 through 2012 were identified. Demographic, clinicopathologic, perioperative, and survival data were collected and analyzed.

RESULTS

There were 87 patients with locally advanced GIST and 71 patients with recurrent/metastatic GIST. The vast majority (95%) of patients with locally advanced GIST required a multivisceral resection; most patients (87%) underwent a microscopically complete (R0) resection. Although 82% of patients had high-risk tumors according to modified NIH criteria or had recurrent/metastatic disease, only 56% of patients received adjuvant TKI therapy. Among patients with locally advanced GIST, 3-year recurrence-free survival and overall survival rates were 65% and 87%, respectively. In contrast, 3-year recurrence-free survival and overall survival rates among patients with recurrent/metastatic GIST were 49% and 82%, respectively. On multivariate analysis, predictors of worse outcomes included high mitotic rate and male sex for patients with locally advanced GIST, and age and lack of adjuvant TKI therapy were associated with adverse outcomes among patients with recurrent/metastatic GIST (all p < 0.05).

CONCLUSIONS

Resection of advanced GIST can be safely accomplished with high rates of R0 resection. Among patients with advanced GIST, TKI therapy was underused. Barriers to the use of TKI therapy in this population should be explored.

Spontaneous rupture of a giant gastrointestinal stromal tumor of the jejunum: a case report and literature review

A few cases of a gastrointestinal stromal tumor (GIST) of the small intestine presenting as rupture have been reported in the medical literature. We report an unusual case of a large GIST of the jejunum that presented as a spontaneous rupture. A 70-year-old man was referred to our hospital because of fever and abdominal pain. An abdominal enhanced computed tomography (CT) scan detected a 10-cm tumor with heterogeneous staining, suggesting necrosis or abscess inside the tumor. The patient was treated with antibiotics but inflammation persisted and an operation was performed. Intraoperative findings showed an outgrowing 10-cm mass in the jejunum near Treitz's ligament. The tumor had ruptured with peritoneal metastasis. The solid parenchyma contained a focal area of necrosis within and the small ulcer located in the wall of the jejunum presented a communication with the large tumor cavity. H&E staining showed spindle-shaped cell proliferation, and immunohistochemical staining showed results positive for c-kit and CD34. The patient received a diagnosis of a GIST (high-risk group) of the jejunum and was treated with imatinib mesylate. The patient has remained in good health without recurrence or metastasis one year after the surgical procedure.