Gastrointestinal stromal tumors—frequency, malignancy, and new prognostic factors: The experience of a single institution

Laparoscopic and Endoscopic Cooperative Dissection for Small Gastric Gastrointestinal Stromal Tumor without Causing Injury to the Mucosa

Objective

To investigate the feasibility of laparoscopic and endoscopic cooperative dissection (LECD) for small gastric gastrointestinal stromal tumors (GISTs) without causing injury to the mucosa, compared with ESD surgery which is widely used now.

Methods

A total of 25 patients with small gastric GISTs who underwent LECD and 20 patients with small gastric GISTs who underwent ESD between October 2014 and June 2016 were included in this study. All patients underwent curative resection for pathologically diagnosed small gastric GISTs. Patients' clinical data were retrospectively analyzed.

Results

In LECD group, the operation was successfully performed in all patients. However, in the ESD group, three patients were transferred to laparoscopic surgery due to intraoperative massive bleeding or intraoperative perforation. No additional targeted chemotherapy drugs for interstitial tumors were prescribed in two groups. There was no difference in the complete tumor capsule rate (100% vs. 90%, p = 0.11), operation time (80.76 ± 13.86 ml vs. 84.05 ± 15.33 ml, p = 0.45), major intraoperative bleeding (0 vs. 5%, p = 0.26), postoperative bleeding (0 vs. 10%, p = 0.11), and postoperative infection (0 vs. 10%, p = 0.11) between the two groups. Compared to ESD (endoscopic submucosal dissection), LECS patients had shorter postoperative indwelling gastric tube (1.04 ± 0.98 d vs. 2.85 ± 0.24 d, p < 0.01), earlier postoperative eating (1.96 ± 0.98 d vs. 3.50 ± 1.15 d, p < 0.01), shorter average postoperative hospital stay (3.44 ± 1.00 d vs. 7.85 ± 1.18 d, p < 0.01), smaller perforation rate (0 vs. 25%, p < 0.05), and fewer surgical supplies. No recurrence or metastasis cases were found between the two groups during the follow-up period, and there were no cases of death due to gastric GISTs.

Conclusion

LECD is a novel surgery for small gastric gastrointestinal stromal tumors that leads to satisfactory short-term outcomes and meets the idea of minimally invasive surgery and rapid recovery; compared with ESD, LECD surgery has some advantages in clinical practice. However, further follow-up is needed to confirm.

Laparoscopic Endoscopic Cooperative Surgery for Gastrointestinal Stromal Tumors

With the development of laparoscopy and digestive endoscopy, multiple laparoscopic and endoscopic cooperative surgeries (LECSs) for gastrointestinal stromal tumors have recently been developed. Classic LECS has been confirmed as a feasible and safe treatment procedure for gastrointestinal stromal tumors with regard to both short-term surgical and long-term oncological outcomes; however, classic LECS has the potential risk of gastric contents or tumor cells spilling into the abdominal cavity because the gastric wall has to be opened during the procedure. Various modified LECS techniques have aimed at further minimizing invasiveness, such as the full-thickness resection method using the nonexposure technique (combination of laparoscopic and endoscopic approaches to neoplasia with a nonexposure technique), nonexposed endoscopic wall-inversion surgery, and closed LECS. This review describes and summarizes the current LECS for gastrointestinal tumor.

The Use of Circulating Tumor DNA for Prognosis of Gastrointestinal Cancers

Gastrointestinal cancers, including oesophageal, gastric and colorectal cancers (CRC) have high rates of disease recurrence despite curative resection. There are a number of recent studies that have investigated the use of circulating tumor DNA (ctDNA) for prognostic value in these cancers. We reviewed studies that had been published prior to March 2018 that assessed the prognostic values of ctDNA in patients with oesophageal and gastric cancers, gastrointestinal stromal tumors (GIST) and CRC. We identified 63 eligible clinical studies that focussed on recurrence and survival. Studies assessed investigated various ctDNA biomarkers in patients with different stages of cancer undergoing surgical resection, chemotherapy and no treatment. For oesophageal squamous cell carcinoma and oesophageal adenocarcinoma, methylation of certain genes such as APC and DAPK have been highlighted as promising biomarkers for prognostication, but these studies are limited and more comprehensive research is needed. Studies focusing on gastric cancer patients showed that methylation of ctDNA in SOX17 and APC were independently associated with poor survival. Two studies demonstrated an association between ctDNA and recurrence and survival in GIST patients, but more studies are needed for this type of gastrointestinal cancer. A large proportion of the literature was on CRC which identified both somatic mutations and DNA methylation biomarkers to determine prognosis. ctDNA biomarkers that identified somatic mutations were more effective if they were personalized based on mutations found in the primary tumor tissue, but ctDNA methylation studies identified various biomarkers that predicted increased risk of recurrence, poor disease free survival and overall survival. While the use of non-invasive ctDNA biomarkers for prognosis is promising, larger studies are needed to validate the clinical utility for optimizing treatment and surveillance strategies to reduce mortality from gastrointestinal cancers.

Systematic review of current prognostication systems for primary gastrointestinal stromal tumors

BACKGROUND

The advent of tyrosine kinase inhibitors as adjuvant therapy has revolutionized the management of GIST and emphasized the need for accurate prognostication systems. Numerous prognostication systems have been proposed for GIST but at present it remains unknown which system is superior. The present systematic review aims to summarize current prognostication systems for primary treatment-naive GIST.

METHODS

A literature review of the Pubmed and Embase databases was performed to identify all published articles in English, from the 1st January 2002 to 28th Feb 2017, reporting on clinical prognostication systems of GIST.

RESULTS

Twenty-three articles on GIST prognostication systems were included. These systems were classified as categorical systems, which stratify patients into risk groups, or continuous systems, which provide an individualized form of risk assessment. There were 16 categorical systems in total. There were 4 modifications of the National Institute of Health (NIH) system, 2 modifications of Armed Forces Institute of Pathology (AFIP) criteria and 3 modifications of Joensuu (modified NIH) criteria. Of the 7 continuous systems, there were 3 prognostic nomograms, 3 mathematical models and 1 prognostic heat/contour maps. Tumor size, location and mitotic count remain the main variables used in these systems.

CONCLUSION

Numerous prognostication systems have been proposed for the risk stratification of GISTs. The most widely used systems today are the NIH, Joensuu modified NIH, AFIP and the Memorial Sloan Kettering Cancer Center nomogram. More validation and comparison studies are required to determine the optimal prognostication system for GIST.

Two staging systems for gastrointestinal stromal tumors in the stomach: which is better?

Background

The prognosis of a gastrointestinal stromal tumor (GIST) is influenced by its anatomic site; however, few studies on the prognosis of gastric GISTs have been reported. The aims of this study were to evaluate long-term prognoses of patients who underwent surgical resection for gastric GISTs and to compare the clinical efficacy of two staging systems: the National Institutes of Health (NIH) consensus criteria and the 7th Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) tumor-node-metastasis (TNM) staging system.

Methods

We conducted a retrospective observational study of 145 patients who underwent surgical resection for gastric GISTs between February 2001 and June 2012 at Pusan National University Hospital (Busan, Korea). Recurrence and 5-year recurrence-free survival (RFS) rates were analyzed.

Results

During a median follow-up period of 44 months (range, 6–144 months), 11 recurrent lesions were detected in 9 patients (6.4%). On multivariate analysis, tumor size (>5 cm), mitotic count (>5/50 high-power fields), and epithelioid and mixed pathological type were significantly associated with recurrence. The overall 5-year RFS rate was 93.4%. Although no statistically significant differences were detected (C-statistic difference P = 0.886), all metrics showed lower values for the UICC/AJCC TNM staging system than for the NIH consensus criteria, suggesting that the UICC/AJCC TNM staging system may be a better model.

Conclusions

The 5-year RFS rate in patients who underwent curative resection for gastric GISTs was excellent. The UICC/AJCC TNM staging system may be more useful than the NIH consensus criteria for risk categorization of patients with gastric GISTs.

Long-term outcomes of endoscopic resection of gastric GISTs

OBJECTIVE

Although the endoscopic treatment of gastric stromal tumors is a recently accepted therapy, the long-term outcomes of this approach remain unknown. The aims of this study were to assess the long-term effectiveness and safety of endoscopic resection for gastric GISTs.

METHODS

A total of 60 consecutive patients undergoing endoscopic resection of gastric GISTs were enrolled in a retrospective single-center study. Clinical data, perioperative complications, histopathologic characteristics of the tumors, and long-term outcomes were recorded.

RESULTS

Sixty patients successfully underwent complete resection of lesions, including 25 cases of endoscopic submucosal dissection (ESD) and 35 cases of endoscopic full-thickness resection (EFTR), with an average tumor size of 1.76 ± 1.55 cm (range 0.5-7.6 cm). The average operation time was 43.97 ± 26.95 min (range 11.7-138.9 min). Two cases were observed with an intraoperative hemorrhage of 200 mL, which were successfully managed by hemostatic forceps. Perforations of 2-11 mm of ESD occurred in four cases (4/25) and were well closed with endoclips, with no conversions to surgical operation. Mucosal laceration of esophagus occurred in 1 case, when a large tumor was removed. The average length of hospitalization was 6.50 ± 3.06 days (range 3-21 days). Out of a total of 60 patients, 44 (73.3%) were at very low risk, 10 (16.7%) were at low risk, 5 (8.3%) were at intermediate risk, and 1 (1.7%) was at high risk. All patients were followed-up for 36.15 ± 12.92 months (range 14-73 months). Primary tumor recurrence occurred in 1 patient who underwent a second operation after 32 months, and no other cases were observed to have either tumor recurrence or metastasis.

CONCLUSIONS

For long-term outcomes, endoscopic resection of ESD or EFTR is a safe and effective approach for removing gastric stromal tumors (<5 cm), and it can be a resection technique for them with no metastasis.

Clinicopathologic analysis of gastrointestinal stromal tumors in duodenum and small intestine

BACKGROUND

The prognosis about duodenal GISTs is debatable. The purpose of this study is to compare the characteristics and the prognostic factors in patients with gastrointestinal stromal tumor (GIST) located in the duodenum with those located in the small intestine.

METHODS

One hundred-one patients with GIST located in the duodenum (n = 40), or small intestine (n = 61) underwent resection between 1996 and 2010. We analyzed clinicopathologic features, surgical outcomes, and prognostic factors.

RESULTS

Five-year survival rate in patients with GIST located in the duodenum and small intestine were 66.6 and 80.8%, respectively (p = 0.018). After survival analysis, high mitotic count and tumor rupture were identified as independent adverse prognostic factors. Advanced T stage and absence of adjuvant imatinib treatment were adverse prognostic factors with marginal statistical significance. The rate of progressive disease was significantly higher in patients with duodenal GISTs (36.8%) than in those with small intestinal GIST (29.6%) (p = 0.024).

CONCLUSIONS

The clinicopathologic findings of duodenal GIST differ from those of small intestinal GIST. Patients with duodenal GIST have a worse prognosis than those with small intestinal GIST. Aggressive treatment including surgical resection should be considered for duodenal GIST, even if the risk is relatively low.

Prognostic impact of gastrointestinal bleeding and expression of PTEN and Ki-67 on primary gastrointestinal stromal tumors

BACKGROUND

Prognostic indicators for gastrointestinal stromal tumors (GISTs) are under investigation. The latest risk classification criteria may still have room for improvement. This study aims to investigate prognostic factors for primary GISTs from three aspects, including clinicopathological parameters, immunohistochemical (IHC) expression of PTEN, and Ki-67 labeling index (LI), and attempts to find valuable predictors for the malignancy potential of primary GISTs.

METHODS

Tumor samples and clinicopathological data from 84 patients with primary GISTs after R0 resection were obtained. Immunohistochemical analysis was performed based on tissue microarray (TMA) to estimate expression of PTEN and Ki-67 in tumor cells.

RESULTS

The cut-off point of Ki-67 LI was determined as 1%, using a receiver operator characteristic test with a sensitivity of 71.7% and a specificity of 64.5%. Univariate analysis demonstrated the following factors as poor prognostic indicators for relapse-free survival (RFS) against a median follow-up of 40.25 months: gastrointestinal (GI) bleeding (P = 0.009), non-gastric tumor location (P = 0.001), large tumor size (P = 0.022), high mitotic index (P < 0.001), high cellularity (P = 0.012), tumor rupture (P = 0.013), absent or low expression of PTEN (P = 0.036), and Ki-67 LI >1% (P = 0.043). Gastrointestinal bleeding (hazard ratio, 3.85; 95% confidence interval, 1.63 to 9.10; P = 0.002) was a negative independent risk predictor in multivariate analysis, in addition to tumor size (P = 0.023), and mitotic index (P = 0.002). In addition, GI bleeding showed a good ability to predict recurrence potential, when included in our re-modified risk stratification criteria.

CONCLUSIONS

This study suggests that GI bleeding is an independent predictor of poor prognosis for RFS in primary GISTs. Expression of PTEN and Ki-67 are correlated with high risk potential and may predict early recurrence in univariate analysis.

New-style laparoscopic and endoscopic cooperative surgery for gastric stromal tumors

AIM: To evaluate the feasibility and safety of a new style of laparoscopic and endoscopic cooperative surgery (LECS), an improved method of laparoscopic intragastric surgery (LIGS) for the treatment of gastric stromal tumors (GSTs).

METHODS: Six patients were treated with the new-style LECS. Surgery was performed according to the following procedures: (1) Exposing and confirming the location of the tumor with gastroscopy; (2) A laparoscopy light was placed in the cavity using the trocar at the navel, and the other two trocars penetrated both the abdominal and stomach walls; (3) With gastroscopy monitoring, the operation was carried out in the gastric lumen using laparoscopic instruments and the tumor was resected; and (4) The tumor tissue was removed orally using a gastroscopy basket, and puncture holes and perforations were sutured using titanium clips.

RESULTS: Tumor size ranged from 2.0 to 4.5 cm (average 3.50 ± 0.84 cm). The operative time ranged from 60 to 130 min (average 83.33 ± 26.58 min). Blood loss was less than 20 mL and hospital stay ranged from 6 to 8 d (average 6.67 ± 0.82 d). The patients were allowed out of bed 12 h later. A stomach tube was inserted for 72 h after surgery, and a liquid diet was then taken. All cases had single tumors which were completely resected using the new-style LECS. No postoperative complications occurred. Pathology of all resected specimens showed GST: no cases of implantation or metastasis were found.

CONCLUSION: New-style LECS for GSTs is a quick, optimized, fast recovery, safe and effective therapy.

Potential indicators predict progress after surgical resection of gastrointestinal stromal tumors

In order to find out the potential indicators predicting prognosis of malignant gastrointestinal stromal tumors (GISTs) after surgical resection, we collected clinical records of 80 patients with malignant GISTs. Tumor location, size, mitotic index, necrosis were compared with the prognosis of malignant GISTs by Kaplan-Meier method and log-rank test. After a median follow-up of 844 days (52-2 145), we found that as National Institutes of Health suggested, tumors with intermediate risk had more favorable prognosis than that with high risk. Their 3-year survival rate were 65.3% and 41.3%, respectively (P < 0.001). Moreover, tumor size and mitotic index were associated with free survival. The 3-year survival rate for patients with tumor size ≤ 10 cm and > 10 cm were 62.3% and 41.8%, respectively (P = 0.002), Tumors with mitotic index ≤ 5/50 HPF had a higher 3-year survival rate than tumors with mitotic index > 5/50 HPF (67.1% versus 40.7%, P = 0.005). The presence of necrosis was directly related to the malignant behavior. The 3-year survival rate for presence and absence necrosis were 50.8% and 64.8% (P = 0.008). From the present study, we can conclude that besides tumors size and mitotic index, tumor location and necrosis also influence on the long-term survival of patient with malignant GISTs after surgical resection.

Exon 11 mutations, Ki67, and p16(INK4A) as predictors of prognosis in patients with GIST

Prognostic biomarkers for GIST are under investigation. The aim of this study was to assess whether exon 11 mutations, Ki67, and p16(INK4A) are predictors of prognosis in GIST. Consecutive GIST cases (n=84) had their specimens evaluated for exon 11 mutations and expression of Ki67 and p16(INK4A). Surgical cases were categorized according to NIH and Miettinen's classification, and survival was analyzed from hospital database. GISTs were predominately gastric (45%) and with spindle cell morphology (74%). The risk category was very low or low in 28%, intermediate in 23%, and high in 49%. Exon 11 mutation was identified in 29 (48%) out of 60 cases studied. There were 12 point mutations, 10 deletions, 4 duplications, and 3 double mutations. A third of GISTs had either high Ki67 index (>3%) or negativity for p16(INK4A). In multivariate analysis, independent predictors of mortality were Ki67>3% (HR=7.3; P=0.036) and high mitotic index (HR=10.4; P=0.043). There was no association between exon 11 mutations and survival. This study suggests that Ki67>3% is an independent predictor of poor prognosis in patients with GIST. Exon 11 mutations and negativity for p16(INK4A) need further studies to address the prognostic value.

Extraluminal laparoscopic wedge resection of gastric submucosal tumors: a retrospective review of 84 cases

BACKGROUND

Laparoscopic resection of gastric stromal tumors is being performed with increased frequency. This study aims to evaluate the feasibility and safety of the extraluminal laparoscopic gastric wedge resection (ELWR) technique.

METHODS

Clinical data of 84 patients who underwent ELWR for gastric submucosal tumors between September 2000 and December 2007 were reviewed and analyzed retrospectively. The operation includes: localization of the tumor, dissection of the omentum, mobilization of the upper stomach and the upper pole of the spleen, exposure of esophago-cardiac junction (ECJ), and wedge resection of the upper part of gastric body and/or the gastric fundus with endoscopic gastrointestinal anastomosis (Endo GIA) stapler.

RESULTS

All of the procedures were performed successfully, with mean operation time of 62.6 +/- 8.9 min and mean intraoperative blood loss of 86.2 +/- 8.1 ml. Through extraluminal laparoscopic wedge resection, complete R0 resection was achieved for all tumors. All surgical margins were negative microscopically. No lesions were missed, nor were there any significant postoperative complications or intraoperative conversions to open surgery. A total of 78.6% of the patients recovered their gastrointestinal functions and began to eat and ambulate within 36 h of the operation. The smallest surgical margins were 0.7-2.5 cm, with a mean distance of 1.4 +/- 0.5 cm. Of the 84 cases of gastric submucosal tumors, 29 cases were leiomyomas, 51 cases were various types of stromal tumors, and 4 other cases were neurofibromas. Mean follow-up duration was 51 +/- 4.3 months (overall follow-up rate 73.8%, 62/84 cases), during which no recurrences or metastases were found.

CONCLUSION

ELWR is a safe, simple, and effective procedure for treating submucosal tumors in the upper part of the stomach. It can avoid intraperitoneal contamination, possible tumor spillage, and postoperative esophageal stenosis, and provides unlimited scope for gastric resection.

Early endoscopic diagnosis and laparoscopic surgery for gastric stromal tumors

AIM: To explore the value of combination of gastroscopy, endoscopic ultrasonography (EUS) and laparoscopy in discovering, diagnosing and treating small gastrointestinal stromal tumors (GIST) of stomach (diameter < 2 cm).

METHODS: From August 2004 to September 2008, 23 patients were found with gastric submucosal tumors by gastroscopy, 16 of which were primarily diagnosed with GIST by EUS. The diameters of tumors are from 0.89 cm to 1.95 cm with an average of 1.42 cm. All of the 16 patients received laparoscopic partial gastrectomy under gastroscope. Following up after operation was carried out to check for tumor recurrence and metastases.

RESULTS: All operations were successfully accomplished within 45-90 min (60 min on average). There were no complications and mortalities. The median postoperative hospital stay was 4 days (range 3-7 d). Of all the 16 cases, 15 cases (93.8%) were verified with GIST by immunohistochemistry and pathology, and 1 case was with schwannoma. For patients suffering from gastric stromal tumors, there were no tumor recurrence and metastases at a mean postoperative following-up of 27 months (range 3-52 mo).

CONCLUSION: It is helpful to diagnose small GIST of stomach and predict the risk before operation by combination of gastroscopy and EUS. Laparoscopic partial gastrectomy under the localization of gastroscopy is safe and effective and the prognosis is favorable.