Prognostic role of tumor necrosis in patients undergoing curative resection for gastric gastrointestinal stromal tumor: a multicenter analysis of 740 cases in China

Surgical Management of Gastric Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are sarcomas that arise from the muscular layer of the gastrointestinal tract. The stomach is the most common location, followed by the small intestine. Surgical resection is the cornerstone of treatment; extensive margins and lymphadenectomy are not routinely required. Commonly utilized resection techniques include wedge gastrectomy, excision and closure of the gastrotomy, and anterior gastrotomy access with internal wedge resection. Tyrosine kinase inhibitors can be utilized in the neoadjuvant setting for cases where a reduction in tumor size would optimize resection, and in the adjuvant setting for high-risk tumors. In select cases, metastasectomy may improve prognosis.

Gastric gastrointestinal stromal tumors: therapeutic strategies and long-term prognosis

OBJECTIVES

This study aimed to evaluate the clinical and prognostic characteristics of primary gastric gastrointestinal stromal tumors (GIST).

METHODS

Patients who underwent resection for primary gastric GIST between January 2002 and December 2017 were included. Recurrence-free survival (RFS) was calculated by Kaplan-Meier analysis, and Cox proportional hazards model was used to identify independent prognostic factors.

RESULTS

Altogether, 653 patients were enrolled. The median patient age was 59 years (range 15-86 years). Open, laparoscopic, and endoscopic resections were performed in 394 (60.3%), 105 (16.1%), and 154 (23.6%) patients, respectively. According to the modified NIH consensus classification, 132 (20.2%), 245 (37.5%), 166 (25.4%), and 88 (13.5%) patients were categorized into very low-, low-, intermediate-, and high-risk, respectively. A total of 136 (20.8%) patients received adjuvant imatinib treatment. The median follow-up time was 78 months (range 4-219 months), and the estimated 5-year RFS rate was 93.0%. In all patients, tumor size and rupture, mitotic counts, and adjuvant imatinib treatment were independent prognostic factors. The prognosis of gastric GIST treated with endoscopic resection was not significantly different from that of laparoscopic or open resection after adjusting for covariates using propensity score matching (log-rank p = .558). Adjuvant imatinib treatment (HR = 0.151, 95%CI 0.055-0.417, p < .001) was a favorable prognostic factor for high-risk patients, but was not associated with prognosis in intermediate-risk patients.

CONCLUSION

Patients with small gastric GISTs who successfully underwent endoscopic resection may have a favorable prognosis. Adjuvant imatinib treatment improve the prognosis of high-risk gastric GISTs, however, its use in intermediate-risk patients remains controversial.

Relationship between multi-slice computed tomography features and pathological risk stratification assessment in gastric gastrointestinal stromal tumors

BACKGROUND

Computed tomography (CT) imaging features are associated with risk stratification of gastric gastrointestinal stromal tumors (GISTs).

AIM

To determine the multi-slice CT imaging features for predicting risk stratification in patients with primary gastric GISTs.

METHODS

The clinicopathological and CT imaging data for 147 patients with histologically confirmed primary gastric GISTs were retrospectively analyzed. All patients had received dynamic contrast-enhanced CT (CECT) followed by surgical resection. According to the modified National Institutes of Health criteria, 147 lesions were classified into the low malignant potential group (very low and low risk; 101 lesions) and high malignant potential group (medium and high-risk; 46 lesions). The association between malignant potential and CT characteristic features (including tumor location, size, growth pattern, contour, ulceration, cystic degeneration or necrosis, calcification within the tumor, lymphadenopathy, enhancement patterns, unenhanced CT and CECT attenuation value, and enhancement degree) was analyzed using univariate analysis. Multivariate logistic regression analysis was performed to identify significant predictors of high malignant potential. The receiver operating curve (ROC) was used to evaluate the predictive value of tumor size and the multinomial logistic regression model for risk classification.

RESULTS

There were 46 patients with high malignant potential and 101 with low-malignant potential gastric GISTs. Univariate analysis showed no significant differences in age, gender, tumor location, calcification, unenhanced CT and CECT attenuation values, and enhancement degree between the two groups (P > 0.05). However, a significant difference was observed in tumor size (3.14 ± 0.94 vs 6.63 ± 3.26 cm, P < 0.001) between the low-grade and high-grade groups. The univariate analysis further revealed that CT imaging features, including tumor contours, lesion growth patterns, ulceration, cystic degeneration or necrosis, lymphadenopathy, and contrast enhancement patterns, were associated with risk stratification (P < 0.05). According to binary logistic regression analysis, tumor size [P < 0.001; odds ratio (OR) = 26.448; 95% confidence interval (CI): 4.854-144.099)], contours (P = 0.028; OR = 7.750; 95%CI: 1.253-47.955), and mixed growth pattern (P = 0.046; OR = 4.740; 95%CI: 1.029-21.828) were independent predictors for risk stratification of gastric GISTs. ROC curve analysis for the multinomial logistic regression model and tumor size to differentiate high-malignant potential from low-malignant potential GISTs achieved a maximum area under the curve of 0.919 (95%CI: 0.863-0.975) and 0.940 (95%CI: 0.893-0.986), respectively. The tumor size cutoff value between the low and high malignant potential groups was 4.05 cm, and the sensitivity and specificity were 93.5% and 84.2%, respectively.

CONCLUSION

CT features, including tumor size, growth patterns, and lesion contours, were predictors of malignant potential for primary gastric GISTs.

Prognostic value of preoperative CT features for disease-free survival in patients with primary gastric gastrointestinal stromal tumors after resection

PURPOSE

Tumor size is an important prognostic factor without consideration of the necrotic and cystic components within tumor for patients with gastrointestinal stromal tumors (GISTs). We aimed to extract the enhancing viable component from the tumor using computed tomography (CT) post-processing software and evaluate the value of preoperative CT features for predicting the disease-free survival (DFS) after curative resection for patients with primary gastric GISTs.

METHODS

132 Patients with primary gastric GISTs who underwent preoperative contrast-enhanced CT and curative resection were retrospectively analyzed. We used a certain CT attenuation of 30 HU to extract the enhancing tissue component from the tumor. Enhancing tissue volume and other CT features were assessed on venous-phase images. We evaluated the value of preoperative CT features for predicting the DFS after surgery. Univariate and multivariate Cox regression analyses were performed to find the independent risk factor for predicting the DFS.

RESULTS

Of the 132 patients, 68 were males and 64 were females, with a mean age of 61 years. The median follow-up duration was 60 months, and 28 patients experienced disease recurrence and distant metastasis during the follow-up period. Serosal invasion (p < 0.001; HR = 5.277) and enhancing tissue volume (p = 0.005; HR = 1.447) were the independent risk factors for predicting the DFS after curative resection for patients with primary gastric GISTs.

CONCLUSION

Preoperative contrast-enhanced CT could be useful for predicting the DFS after the surgery of gastric GISTs, and serosal invasion and enhancing tissue volume were the independent risk factors.

Clinicopathological features of Gastrointestinal Stromal Tumors and review of the literature

Objective: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasias of the gastrointestinal system (GIS). The malignancy potential of GISTs may vary ranging from indolent tumors to progressive malignant tumors. This study aims to define clinicopathological and immunohistochemical features of GISTs diagnosed in our institute with a review of the literature. Method: A total of 28 GIST cases were included in the study. The Hematoxylin&Eosin stained slides of surgical resection materials and cell blocks and immunohistochemistry performed slides were reviewed by a pathologist. The immunohistochemical expression with CD117, DOG-1, CD34, SMA, and S100 was scored between 0 and 3 points according to staining intensity. Descriptive statistics were used in the study. The demographic data, prognostic histopathological, and immunohistochemical findings are evaluated with the literature indications. Result: Eleven of the cases were male and seventeen were female. The age range was 18-88. The most common site of GISTs was the stomach, followed by the small intestine, colorectal region, and, esophagus. Twenty of the tumors were resected surgically, four were endoscopic biopsy material and four were fine-needle aspiration biopsies. The tumor size in measurable materials ranged from 0,2 to 22 cm. The mitotic count in 50 HPF ranges from 0 to 10. Seven of the GISTs were high grade and the remaining 21 were low grade. The majority of the cases were composed of spindle cells, 3 were epithelioid and 3 were the mixed type with spindle and epitheloid cells. Conclusion: A variety of criteria has been proposed to estimate the malignancy potential of GISTs and predict prognosis but definite prognostic criteria remain uncertain. Further studies with larger series of GISTs consisting of different types of biopsy materials may help define criteria to predict prognosis precisely.

Comparison of Computed Tomography Features of Gastric and Small Bowel Gastrointestinal Stromal Tumors With Different Risk Grades

OBJECTIVE

This study aimed to compare the computed tomography (CT) features of gastric and small bowel gastrointestinal stromal tumors (GISTs) and further identify the predictors for risk stratification of them, respectively.

METHODS

According to the modified National Institutes of Health criteria, patients were classified into low-malignant potential group and high-malignant potential group. Two experienced radiologists reviewed the CT features including the difference of CT values between arterial phase and portal venous phase (PVPMAP) by consensus. The CT features of gastric and small bowel GISTs were compared, and the association of CT features with risk grades was analyzed, respectively. Determinant CT features were used to construct corresponding models.

RESULTS

Univariate analysis showed that small bowel GISTs tended to present with irregular contour, mixed growth pattern, ill-defined margin, severe necrosis, ulceration, tumor vessels, heterogeneous enhancement, larger size, and marked enhancement compared with gastric GISTs. According to multivariate analysis, tumor size (P < 0.001; odds ratio [OR], 3.279), necrosis (P = 0.008; OR, 2.104) and PVPMAP (P = 0.045; OR, 0.958) were the independent influencing factors for risk stratification of gastric GISTs. In terms of small bowel GISTs, the independent predictors were tumor size (P < 0.001; OR, 3.797) and ulceration (P = 0.031; OR, 4.027). Receiver operating characteristic curve indicated that the CT models for risk stratification of gastric and small bowel GISTs both achieved the best predictive performance.

CONCLUSIONS

Computed tomography features of gastric and small bowel GISTs are different. Furthermore, the qualitative and quantitative CT features of GISTs may be favorable for preoperative risk stratification.

A CT-based nomogram for predicting the malignant potential of primary gastric gastrointestinal stromal tumors preoperatively

PURPOSE

To develop and validate a computerized tomography (CT)-based nomogram for predicting the malignant potential of primary gastric gastrointestinal stromal tumors (GISTs).

METHODS

The primary and validation cohorts consisted of 167 and 39 patients (single center, different time periods) with histologically confirmed primary gastric GISTs. Clinical data and preoperative CT images were reviewed. The association of CT characteristics with malignant potential was analyzed using univariate and stepwise logistic regression analyses. A nomogram based on significant CT findings was developed for predicting malignant potential. The predictive accuracy of the nomogram was determined by the concordance index (C-index) and calibration curves. External validation was performed with the validation cohort.

RESULTS

CT imaging features including tumor size, tumor location, tumor necrosis, growth pattern, ulceration, enlarged vessels feeding or draining the mass (EVFDM), tumor contour, mesenteric fat infiltration, and direct organ invasion showed significant differences between the low- and high-grade malignant potential groups in univariate analysis (P < 0.05). Only tumor size (> 5 cm vs ≤ 5 cm), location (cardiac/pericardial region vs other), EVFDM, and mesenteric fat infiltration (present vs absent) were significantly associated with high malignant potential in multivariate logistic regression analysis. Incorporating these four independent factors into the nomogram model achieved good C-indexes of 0.946 (95% confidence interval [CI] 0.899-0.975) and 0.952 (95% CI 0.913-0.977) in the primary and validation cohorts, respectively. The cutoff point was 0.33, with sensitivity, specificity, and diagnostic accuracy of 0.865, 0.915, and 0.780, respectively.

DISCUSSION

Primary gastric GISTs originating in the cardiac/pericardial region appear to be associated with higher malignant potential. The nomogram consisting of CT features, including size, location, EVFDM, and mesenteric fat infiltration, could be used to accurately predict the high malignant potential of primary gastric GISTs.

Utility of preoperative computed tomography features in predicting the Ki-67 labeling index of gastric gastrointestinal stromal tumors

PURPOSE

To evaluate the value of preoperative computed tomography (CT) features including morphologic and quantitative features for predicting the Ki-67 labeling index (Ki-67LI) of gastric gastrointestinal stromal tumors (GISTs).

METHODS

We retrospectively included 167 patients with gastric GISTs who underwent preoperative contrast-enhanced CT. We assessed the morphologic features of preoperative CT images and the quantitative features including the maximum diameter of tumor, total tumor volume, mean total tumor CT value, necrosis volume, necrosis volume ratio, enhanced tissue volume, and mean CT value of enhanced tissue. Potential predictive parameters to distinguish the high-level Ki-67LI group (>4%, n = 125) from the low-level Ki-67LI group (≤4%, n = 42) were compared and subsequently determined in multivariable logistic regression analysis.

RESULTS

Growth pattern (p = 0.036), shape (p = 0.000), maximum diameter (p = 0.018), total tumor volume (p = 0.021), mean total tumor CT value (p = 0.009), necrosis volume (p = 0.006), necrosis volume ratio (p = 0.000), enhanced tissue volume (p = 0.027), and mean CT value of enhanced tissue (p = 0.004) were significantly different between the two groups. Multivariate logistic regression analysis indicated that lobulated/irregular shape (odds ratio [OR] = 3.817; p = 0.000) and high necrosis volume ratio (OR = 1.935; p = 0.024) were independent factors of high-level Ki-67LI.

CONCLUSIONS

Higher necrosis volume ratio in combination with lobulated/irregular shape could potentially predict high expression of Ki-67LI for gastric GISTs.

Role of Multidetector CT Imaging in the Risk Stratification of Gastrointestinal Stromal Tumors (GISTs)–A Retrospective Analysis

Background Gastrointestinal stromal tumors (GISTs) are the most common gastrointestinal mesenchymal neoplasms which can arise from any part of the gastrointestinal tract (GIT) or an extraintestinal location. Size and the organ of origin are the major imaging inputs expected from the radiologist. However, it is worthwhile to find out which imaging characteristics on MDCT correlate with risk stratification. This knowledge would help the clinician in treatment planning and prognostication. The aim of this retrospective study is to evaluate the various MDCT imaging characteristics of GISTs and find out which parameters have significant association with risk and subsequent development of metastasis on follow-up whenever it was possible.

Materials and Methods This is a retrospective study conducted on 45 histopathologically proven cases of GIST from two institutions by searching from the digital archives. The following imaging parameters were analyzed: maximum size in any plane, organ of origin, shape (round, ovoid or irregular), margin (well-defined or ill-defined), surface (smooth or lobulated), percentage of necrosis, growth pattern, enhancement characteristics–both intensity (mild, moderate or significant) and pattern (homogenous vs. heterogenous), calcification, infiltration into adjacent organs, and presence of metastasis at presentation or on follow-up.

Results CT morphological parameters of significance in risk stratification as per our study include tumor necrosis, predominant cystic change, irregular and lobulated shape/surface characteristics, and adjacent organ infiltration.

The parameters which were associated with development of metastasis were size > 5 cm, necrosis > 30%, and the presence of adjacent organ infiltration.

Conclusion The radiologist has an important role in ascertaining the size of tumor as well as the organ of origin accurately to guide the clinician in risk calculation and subsequent prognostication. In addition, certain CT characteristics mentioned above, namely, tumor size, significant necrosis/cystic changes, irregular/lobulated contour, and invasion of adjacent organs, help in risk stratification and in predicting metastasis/poor prognosis.

Mutational characteristics of gastrointestinal stromal tumors: A single-center analysis of 302 patients

Gastrointestinal stromal tumors (GISTs) represent a spectrum of tumors characterized by variable behaviors and activating mutations in KIT proto-oncogene, receptor tyrosine kinase (KIT) or platelet derived growth factor receptor α (PDGFRA) genes. However, whether genotype analysis should be regarded as a prognostic indicator remains unclear. In the present study, clinicopathological data and the mutation phenotypes of KIT and PDGFRA genes were assessed in a series of 302 patients with GISTs at a single center. Univariate and multivariate Cox regression analyses were performed to identify the clinicopathological and mutational factors associated with relapse-free survival (RFS) in patients who had undergone complete primary GIST resection. KIT and PDGFRA mutations were identified in 233 (77.2%) and 30 (9.9%) cases, respectively. The following clinicopathological parameters were significantly associated with a shorter RFS: Male, non-gastric tumor origin, larger tumor size (>5 cm), high mitotic activity (>5/50 high-power fields), necrosis and epithelioid morphology. Tumors at non-gastric sites, with high National Institutes of Health risk classification, high World Health Organization (WHO) grade and KIT deletion involving codons 557/558/559 exhibited a significantly higher risk of progression. In the Cox regression model, KIT deletion involving codons 557/558/559, non-gastric origin and high WHO grade were independent indicators of RFS. The adverse prognosis associated with KIT deletions involving codons 557/558/559 was also observed for gastric GISTs. Conversely, spindle morphology, KIT exon 11 substitution and PDGFRA exon 18 mutation were associated with a longer RFS and lower rate of relapse. Furthermore, the coexistence of KIT exon 11 deletion and exon 13 duplication was observed in one tumor, with adverse prognostic features. Heterogeneity affecting morphology, immunostaining and genotype was identified in 4 cases. In addition, the presence of succinate dehydrogenase-deficient GIST was found in 5 cases (3.6%). In conclusion, the tumor genotype with regard to KIT and PDGFRA mutations exhibited prognostic significance for the risk of GIST progression and may be helpful for the optimization of tailored adjuvant therapy.

Tumor necrosis is significantly associated with reduced recurrence-free survival after curative resection of gastrointestinal stromal tumors

BACKGROUND OBJECTIVES

The impact of tumor necrosis as a prognostic factor in gastrointestinal stromal tumor (GISTs) is still debated. The objective was to determine whether tumor necrosis is an independent risk factor for survival in patients with GISTs.

METHODS

Patients undergoing surgery for primary GIST from March 2003 to October 2018 at two sarcoma referral centers were retrospectively identified. Patients who received neoadjuvant imatinib were excluded. Multivariable Cox regression models were produced, to assess whether tumor necrosis was an independent predictor of either overall or recurrence-free survival.

RESULTS

Forty-one out of 195 (21.0%) patients had tumor necrosis. Tumor necrosis was associated with a significantly higher modified National Institute of Health risk score, with 29 out of 41 (70.7%) patients with necrosis classified as high risk, compared to 52 out of 153 (34.0%) without (p < .001). Tumor necrosis was found to be independently predictive of recurrence-free survival (hazard ratio: 5.26, 95% CI: 2.62-10.56, p < .001) on multivariable analysis. At 5 years, 44.3% of patients with necrosis had either died or developed recurrence, compared to 9.9% of those without.

CONCLUSION

Tumor necrosis is an independent predictor of recurrence-free survival in patients with operable GISTs. It should be routinely reported by pathologists, and used by clinicians when counseling patients and deciding on adjuvant therapy.

Gastrointestinal Stromal Tumours (GIST): Indian Experience of Rare Malignancy

GISTs are rare tumours of the GI tract arising from the intestinal cells of Cajal. Though various risk stratification systems have been proposed, none has been universally accepted. We audited the survival and recurrence patterns in our patients and evaluated clinicopathological features to identify prognostic factors affecting survival. We conducted a retrospective analysis of patients treated at our hospital from 1999 to 2012. Patient variables, clinicopathological factors and treatment variables were collected. Sixty-three patients were evaluated and treated at our institute of which 38 were non-metastatic. The most common site of origin was the stomach. On univariate analysis, presence of metastasis, male gender, high mitotic rate, non-gastric primary and epithelioid histology were significantly associated with poor overall survival. Tumour size > 10 cm, mitotic rate > 10/50 hpf and presence of necrosis significantly affected disease-free survival for non-metastatic patients. Multivariate analysis showed higher mitotic rate and non-gastric primary to correlate with worse outcome. In our experience, a high mitotic rate and non-gastric primary independently predicted a poor prognosis in GIST.

Evaluation of Ki67 Index in Endoscopic Ultrasound-Guided Fine Needle Aspiration Samples for the Assessment of Malignancy Risk in Gastric Gastrointestinal Stromal Tumors

BACKGROUND

The risk of malignancy in resected gastrointestinal stromal tumors (GISTs) depends on tumor size, location, and mitotic index. Reportedly, the Ki67 index has a prognostic value in resected GISTs. We aimed to analyze the accuracy of endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) samples with reference to Ki67 index, using surgical specimens as the gold standard.

METHODS

Fifty-five patients who underwent EUS-FNA followed by surgical resection for gastric GISTs were retrospectively analyzed. Patients' age and sex; tumors' size and location; mitotic index, cell type, cellularity, pleomorphism, presence of ulceration, hemorrhage, necrosis, mucosal or serosal invasion, growth pattern, and Ki67 index based on pathology were investigated.

RESULTS

Location in fundus, ulceration, hemorrhage, mucosal invasion, and Ki67 index in surgical specimens were significant in predicting high-risk groups (p < 0.05) on univariate analysis. Frequency of bleeding (p = 0.034) and the Ki67 index (p = 0.018) were the only independent significant factors in multivariate analysis. The optimal cutoff level of Ki67 was 5%, with 88.2% sensitivity and 52.8% specificity (p = 0.021). The mean Ki67 index was lower in EUS-FNA samples than in surgical specimens (2% [1-15] versus 10% [1-70], p = 0.001). The rank correlation coefficient value of Ki67 was 0.199 (p = 0.362) between EUS-FNA and surgical samples and showed no reliability for EUS-FNA samples.

CONCLUSION

The Ki67 index in resected specimens correlated with high-risk GISTs, although it had no additive value to the current criteria. The Ki67 index in EUS-guided FNA samples is not a reliable marker of proliferation in GISTs.

Impact of Prognostic Nutritional Index on Terminal Cancer Patients

BACKGROUND

In terminal cancer patients (TCPs), one of the most important things is to define the survival to help the main responsible physicians, patients, and main caregivers make decisions, set goals, and work across the end-of-life strategies.

PATIENTS AND METHODS

We retrospectively reviewed the medical files of TCPs, who died during September 2011 and December 2017, to recognize the correlation between prognostic nutritional indices (PNIs) and survival in those subtypes of patients. The receiver operating characteristic (ROC) curve was used to identify the cutoff value of PNI.

RESULTS

A total of 858 TCPs were eligible and included, the median age was 62 years (range: 18-107). The most common primary cancer sites were colorectal cancer in 151 patients (17.6%), hepatobiliary in 129 (15%), lung cancer in 115 (13.4%), breast cancer in 114 (13.3%), and genitourinary in 80 (9.3%). The mean value of PNI for all cancer types was 32.9 ± 6.7. The values showed different levels across cancer types. For patients who lived >2 weeks, PNI was 36.7 compared with that who died within 2 weeks was 29.3, which was a statistically significant (P < 0.001). By the ROC curve, the cutoff value of PNI was 32.3 and area under the curve was 0.888. The sensitivity, specificity, positive predictive value, and negative predictive value were 91.28% (95% confidence interval [CI]: 88.2-93.8), 71.09% (95% CI: 66.5-75.4), 76.5% (95% CI: 73.7-79.2), and 88.8% (95% CI: 85.3-91.5), respectively.

CONCLUSION

The PNI is an easy and an applicable biomarker to estimate life expectancy in TCPs.

Correlation between Three-Dimensional Volume and Malignant Potential of Gastrointestinal Stromal Tumors (GISTs)

Background and purpose: Gastrointestinal stromal tumors (GISTs) are rare diseases of the gastrointestinal tract but they are the most common gastrointestinal tumors of mesenchymal origin. Since most GISTs have malignant potential, their probability of malignant progression must be evaluated. This study was conducted to examine the correlation between three-dimensional GIST volume measured by CT and malignant potential. Materials and methods: A retrospective study was performed on 70 patients diagnosed with GIST after surgical resection in Hanyang University Seoul Hospital from 2012 to 2017. Linear regression analysis was used to establish which between the length of the long axis of GISTs, originally considered a predictor of malignancy, and their volume was a more accurate predictor of malignancy. Tumor dimensions were measured by CT. Results: Data were analyzed using the chi-square test or Student’s t-test and logistic regression. Of the GISTs, 53 (75.71%) were in the stomach, 3 (4.29%) in the small intestine, and 14 (20.0%) in the large intestine. The mean age of the malignant GIST group was significantly higher than that of the benign GIST group (p = 0.032), their tumor long axes were significantly greater (p = 0.073), their tumor volumes were significantly larger (p = 0.001), and the frequency of tumor necrosis was higher (p = 0.001). In multivariate analysis, malignant GIST was associated with location in organs other than the stomach (OR 7.846, 95% CI 1.293–47.624, p = 0.025), longer axis (OR 1.037, 95% CI 1.011–1.065, p = 0.006), larger volume (OR 1.003, 95% CI 1.000–1.006, p = 0.029), and necrosis (OR 12.222, 95% CI 1.945–76.794, p = 0.008). The mean age of the recurrent GIST group was higher than that of the non-recurrent group (p = 0.045), their tumor long axes were significantly longer (p = 0.005), and their volumes were greater, but this last difference was not significant (p = 0.072). Conclusions: Tumor volume can be considered an additional risk factor in assessing the malignant potential of GISTs and tends to increase in recurrent GISTs.

Prognostic Indicators for Gastrointestinal Stromal Tumors: A Review

Gastrointestinal stromal tumors (GISTs) are potentially malignancies that can occur anywhere in the digestive tract. Tyrosine kinase inhibitors (TKIs) such as imatinib have proven effective since the discovery of KIT and PDGFRA. The current version of NCNN, ESMO and EURACAN guidelines recognized that the three main prognostic factors are the mitotic rate, tumor size and tumor site. In addition, tumor rupture is also recognized as an independent risk factor. However, recent evidence shows that various types of gene mutations are associated with prognosis, and influencing factors such as gastrointestinal bleeding and high Ki67 index have been associated with poor prognosis. It shows that the current risk classification is still insufficient and controversial. With the emergence of more and more lack mutation in KIT/PDGFRA GISTs (KIT/PDGFRA wild-type GISTs) or drug resistance genes, primary and secondary drug resistance problems are caused, which makes the treatment of late or metastatic GIST face challenges. Therefore, this article will review the clinicopathological characteristics of GIST, the special molecular subtypes and other factors that may affect prognosis. We will also explore reliable prognostic markers for better postoperative management and improve the prognosis of patients with GIST.

Extracellular K+ Dampens T Cell Functions: Implications for Immune Suppression in the Tumor Microenvironment

Background: Dying tumor cells release intracellular potassium (K⁺), raising extracellular K⁺ ([K⁺]_e) in the tumor microenvironment (TME) to 40-50 mM (high-[K⁺]_e). Here, we investigated the effect of high-[K⁺]_e on T cell functions. Materials and Methods: Functional impacts of high-[K⁺]_e on human T cells were determined by cellular, molecular, and imaging assays. Results: Exposure to high-[K⁺]_e suppressed the proliferation of central memory and effector memory T cells, while T memory stem cells were unaffected. High-[K⁺]_e inhibited T cell cytokine production and dampened antitumor cytotoxicity, by modulating the Akt signaling pathway. High-[K⁺]_e caused significant upregulation of the immune checkpoint protein PD-1 in activated T cells. Although the number of K_Ca3.1 calcium-activated potassium channels expressed in T cells remained unaffected under high-[K⁺]_e, a novel K_Ca3.1 activator, SKA-346, rescued T cells from high-[K⁺]_e-mediated suppression. Conclusion: High-[K⁺]_e represents a so far overlooked secondary checkpoint in cancer. K_Ca3.1 activators could overcome such "ionic-checkpoint"-mediated immunosuppression in the TME, and be administered together with known PD-1 inhibitors and other cancer therapeutics to improve outcomes.

The prognostic value of gastrointestinal bleeding in gastrointestinal stromal tumor: A propensity score matching analysis

Background and objectives

Whether gastrointestinal (GI) bleeding indicates gastrointestinal stromal tumor (GIST) rupture and impacts prognosis is unclear. We examined the prognostic value of GI bleeding in GIST.

Methods

Primary GIST patients with (GB group) or without (NGB group) initial symptoms of GI bleeding were retrospectively studied. Propensity score matching (PSM) was conducted to reduce confounders.

Results

Eight hundred patients were enrolled. Male gender [odds ratio (OR) = 1.517, P = 0.011], tumors in the small intestine (OR = 2.539, P < 0.001), and tumor size 5‐10 cm (OR = 2.298, P = 0.004) increased the odds of GI bleeding; age >60 years decreased the odds (OR = 0.683, P = 0.031). After PSM, 444 patients were included (222 in each group). Relapse‐free survival (RFS) (P = 0.001) and overall survival (OS) (P = 0.002) were both superior in the GB group. In subgroup analysis, the GB group achieved a superior RFS (P = 0.005) and OS (P = 0.007) in patients with small intestine GIST, but not stomach or colorectal GIST.

Conclusions

GIST patients with age <60, male gender, tumors located in the small intestine, and tumors 5‐10 cm in size had a higher risk of GI bleeding. GIST patients with GI bleeding had a superior RFS and OS. This difference was statistically significant only in small intestine GIST.

Relationship of prognostic nutritional index with prognosis of gastrointestinal stromal tumors

Background: The prognostic nutritional index (PNI) is a useful parameter that indicates the immunonutritional status of patients with malignant tumors. In this retrospective study, we aimed to investigate the value of PNI to predict the outcome of gastrointestinal stromal tumors (GISTs).

Material and methods: This study enrolled 431 GIST patients who underwent curative resection from January 2000 to December 2012. A receiver operating characteristic (ROC) curve analysis was used to identify the cutoff value of PNI, neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR). Survival curves were produced using the Kaplan-Meier method and were compared using a log-rank test. The Cox proportional hazards model was used to identify independent prognostic factors.

Results: Of the 431 patients, 209 (48.5%) were male and 222 (51.5%) were female. The median age was 56 (range 20-80 years old). The PNI cutoff value was 47.45, with a sensitivity of 61.1 % and a specificity of 69.9 %. Compared to the PNI-low group (PNI < 47.45), the PNI-high group (PNI ≥47.45) had a significantly longer recurrence-free survival (RFS) (5-year RFS rate 89.9% versus 70.8%, p<0.001). Patients with higher PNI (p<0.001), lower NLR (p<0.001) and lower PLR (p=0.002) had significant better prognosis. PNI was found to be an independent prognostic factor of RFS (hazard ratio [HR] =1.967, 95% confidence interval [95% CI]: 1.243-3.114, p=0.004).

Conclusions: PNI is a simple and useful marker that can predict the prognosis of GIST.

Clinicopathological Outcomes and Prognosis of Elderly Patients (≥ 65 Years) with Gastric Gastrointestinal Stromal Tumors (GISTs) Undergoing Curative-Intent Resection: a Multicenter Data Review

BACKGROUND

The most common site of gastrointestinal stromal tumors (GISTs) is the stomach, and gastric GISTs (gGISTs) occur most often in elderly patients. However, the clinicopathological features, treatment patterns, and prognosis of elderly patients with gGISTs remain unclear.

METHODS

We retrospectively collected clinicopathological and prognostic data for patients with primary gGISTs who underwent curative-intent resection at 10 medical centers in China from 1998 to 2015.

RESULTS

Over the 18 years, 10 medical centers treated 1846 patients with primary gGISTs by curative-intent resection. The median age was 59 (range 18-91) years. The patients were classified into two groups according to age, namely an elderly group (≥ 65 years of age) and a nonelderly group (< 65 years of age). The elderly group had more comorbidities (40.7% vs 23.5%, p = 0.011), a higher rate of postoperative complications (14.4% vs 8.7%, p = 0.031), and a lower proportion of intermediate/high-risk patients who received adjuvant therapy (30.0% vs 66.8%, p = 0.001) than did the nonelderly group. Regarding pathological outcomes, a significant difference in tumor necrosis was observed between the two groups (p = 0.002), and more cases of tumor necrosis occurred in the elderly group than in the nonelderly group. Regarding postoperative recovery outcomes, no significant difference was observed between the two groups. Univariate analysis showed that age, postoperative complications, adjuvant therapy, tumor size, mitotic count, modified National Institutes of Health (NIH) risk category, and tumor necrosis were factors that affected disease-free survival (DFS). Multivariate analysis showed that modified NIH risk category was the only independent factor affecting DFS. The 5-year DFS rates in the nonelderly and elderly groups were 88.1% and 81.4%, respectively (p = 0.034), and the 5-year overall survival (OS) rates were 90.4% and 85.5% (p = 0.038), respectively.

CONCLUSIONS

Currently, the treatment patterns for elderly patients with gGISTs remain the same as those for young patients with gGISTs. Elderly gGIST patients had more comorbidities and postoperative complications than did nonelderly gGIST patients, and fewer elderly gGIST patients received postoperative adjuvant therapy. Elderly gGIST patients also had a higher rate of tumor necrosis and worse DFS and OS than did young gGIST patients. Further exploration into the diagnosis and treatment patterns of elderly patients is therefore essential.

Prognostic value of tumor necrosis in gastrointestinal stromal tumor: A meta-analysis

BACKGROUND AND AIMS

There is currently no consensus regarding the influence of tumor necrosis on the prognosis of gastrointestinal stromal tumors (GISTs). Therefore, we conducted a meta-analysis to determine the prognostic role of tumor necrosis in patients with GIST.

METHODS

PubMed, Embase, and Web of Science electronic databases were searched from their inception to March 2018. Studies reporting data on the relationship between tumor necrosis and GIST prognosis were eligible. The measure of the effect of interest was the odds ratios (ORs) with 95% confidence intervals (CIs). This study has been registered in the Prospero (number CRD42018096036).

RESULTS

In total, 18 studies including 2320 patients were identified. The total odds of tumor necrosis were associated with a poor GIST prognosis (OR = 5.54, 95% CI = 4.39-6.99). Subgroup analysis of different observed outcomes indicated that tumor necrosis was associated with a decreased disease-free survival (OR = 7.08, 95% CI = 4.78-10.49), recurrence-free survival (OR = 3.96, 95% CI = 2.48-6.32), and overall survival (OR = 4.29, 95% CI = 2.02-9.13). In addition, any tumor site, tumor size, follow-up time, ethnicity, different outcomes of GIST, and different degrees of positive staining of immunohistochemical markers subgroups showed a significantly increased risk of a poor prognosis.

CONCLUSIONS

Tumor necrosis may likely predict a poorer prognosis for GIST. However, further well-designed prospective studies with large sample size are required in the future.

Prognostic role of tumor necrosis in patients undergoing curative resection for gastric gastrointestinal stromal tumor: a multicenter analysis of 740 cases in China

Tumor necrosis is associated with poor clinical outcomes in many malignancies. We aimed to determine whether tumor necrosis was an independent predictor of outcomes in gastric gastrointestinal stromal tumors (GISTs). We retrospectively analyzed data from 740 patients undergoing curative resection for gastric GIST at four centers between 2001 and 2015. Disease‐free survival (DFS) was estimated with the Kaplan–Meier method, and associations with prognosis were assessed with Cox regression models. Tumor necrosis was present in 122 cases (16.5%). The prevalence of tumor necrosis increased with higher risk‐stratification, including 0.7%, 7.4%, 17.3%, and 39.3% for very low‐, low‐, intermediate‐ and high‐risk tumors, respectively (P < 0.001). Tumor necrosis was associated with aggressive tumor biology, such as larger tumor size, higher mitotic index, tumor rupture, and presence of nuclear atypia (all P < 0.05). Multivariate analysis revealed that tumor necrosis was an independent predictor of unfavorable DFS (HR: 2.641; 95% CI: 1.359–5.131; P = 0.004). When stratified by the modified National Institutes of Health (NIH) classification, tumor necrosis still independently predicted DFS in high‐risk patients (P = 0.001) but not in non‐high‐risk patients (P = 0.349). The 5‐year DFS rate in high‐risk patients with and without tumor necrosis was 56.5% and 82.9%, respectively (P = 0.004). Notably, the prognostic significance of tumor necrosis was maintained when the patients were stratified by age, sex, tumor location, tumor size, and mitotic index (All P < 0.05). Tumor necrosis is a useful predictor of outcomes in gastric GIST, especially in high‐risk patients. Based on these results, we recommend that the current NIH classification should be further improved and expanded to include tumor necrosis as a valuable prognostic indicator.