Quality of Surgery and Outcome in Localized Gastrointestinal Stromal Tumors Treated Within an International Intergroup Randomized Clinical Trial of Adjuvant Imatinib

Prognostic impact of positive microscopic margins (R1 resection) in patients with GIST (gastrointestinal stromal tumours): Results of a multicenter European study

BACKGROUND

Although several prognostic factors in GIST have been well studied such as tumour size, mitotic rate, or localization, the influence of microscopic margins or R1 resection remains controversial. The aim of this study was to evaluate the influence of R1 resection on the prognosis of GIST in a large multicentre retrospective series of patients.

METHODS

From 2001 to 2013, 1413 patients who underwent surgery for any site of GIST were identified from 61 European centers. 1098 patients were included, excluding synchronous metastases, concurrent malignancies, R2 resection or GIST recurrence. Tumour rupture (TR) was reclassified according to the Oslo sarcoma classification. Cox proportional hazards ratio and Kaplan-Meier survival estimates were used to analyse 5-year recurrence-free survival (RFS).

RESULTS

Of 1098 patients, 38 (3%) underwent R1 resection with a risk of TR of 11%. The 5-year RFS was 89.6% with a median follow-up of 81 months [range: 31.2-152 months]. On univariate analysis, lower RFS was significantly associated with R1 resection [HR = 2.13; p = 0.04], high risk score according to the modified NIH classification, administration of adjuvant therapy [HR = 2.24; p < 0.001] and intraoperative complications [HR = 2.82; p < 0.001]. Only intraoperative complications [HR = 1.79; p = 0.02] and high risk according to the modified NIH classification including the updated definition of TR [HR = 3.43; p = 0.04] remained significant on multivariate analysis.

CONCLUSION

This study shows that positive microscopic margins are not an independent predictive factor for RFS in GIST when taking into account the up-dated classification of TR. R1 resection may be considered a reasonable alternative to avoid major functional sequelae and should not lead to reoperation.

Convolutional neural network applied to preoperative venous-phase CT images predicts risk category in patients with gastric gastrointestinal stromal tumors

OBJECTIVE

The risk category of gastric gastrointestinal stromal tumors (GISTs) are closely related to the surgical method, the scope of resection, and the need for preoperative chemotherapy. We aimed to develop and validate convolutional neural network (CNN) models based on preoperative venous-phase CT images to predict the risk category of gastric GISTs.

METHOD

A total of 425 patients pathologically diagnosed with gastric GISTs at the authors' medical centers between January 2012 and July 2021 were split into a training set (154, 84, and 59 with very low/low, intermediate, and high-risk, respectively) and a validation set (67, 35, and 26, respectively). Three CNN models were constructed by obtaining the upper and lower 1, 4, and 7 layers of the maximum tumour mask slice based on venous-phase CT Images and models of CNN_layer3, CNN_layer9, and CNN_layer15 established, respectively. The area under the receiver operating characteristics curve (AUROC) and the Obuchowski index were calculated to compare the diagnostic performance of the CNN models.

RESULTS

In the validation set, CNN_layer3, CNN_layer9, and CNN_layer15 had AUROCs of 0.89, 0.90, and 0.90, respectively, for low-risk gastric GISTs; 0.82, 0.83, and 0.83 for intermediate-risk gastric GISTs; and 0.86, 0.86, and 0.85 for high-risk gastric GISTs. In the validation dataset, CNN_layer3 (Obuchowski index, 0.871) provided similar performance than CNN_layer9 and CNN_layer15 (Obuchowski index, 0.875 and 0.873, respectively) in prediction of the gastric GIST risk category (All P >.05).

CONCLUSIONS

The CNN based on preoperative venous-phase CT images showed good performance for predicting the risk category of gastric GISTs.

Referral patterns of GIST patients: data from a nationwide study

BACKGROUND

This study compares the characteristics, referral and treatment patterns and overall survival (OS) of gastrointestinal stromal tumor (GIST) patients treated in reference and non-reference centers in the Netherlands.

PATIENTS AND METHODS

This retrospective cohort study on patients diagnosed between 2016 and 2019, utilises data from the Netherlands Cancer Registry and the Dutch Nationwide Pathology Database. Patients were categorized into two groups: patients diagnosed in or referred to reference centers and patients diagnosed in non-reference centers without referral.

RESULTS

This study included 1,550 GIST patients with a median age of 67.0 in reference and 68.0 years in non-reference centers. Eighty-seven per cent of patients were diagnosed in non-reference centers, of which 36.5% (493/1,352) were referred to a reference center. Referral rates were higher for high-risk (62.2% [74/119]) and metastatic patients (67.2% [90/134]). Mutation analysis was performed in 96.9% and 87.6% of these cases in reference and in non-reference centers (p < 0.01), respectively. Systemic therapy was given in reference centers versus non-reference in 89.5% versus 82.0% (p < 0.01) of high-risk and in 94.1% versus 65.9% (p < 0.01) of metastatic patients, respectively. The proportion of positive resection margins and tumor rupture did not differ between reference and non-reference centers. Median OS was not reached.

CONCLUSION

A substantial amount of metastatic GIST patients in non-reference centers did not receive systemic treatment. This might be due to valid reasons. However, optimisation of the referral strategy of GIST patients in the Netherlands could benefit patients. Further research is needed to explore reasons for not starting systemic treatment in metastatic GIST patients.

2023 GEIS Guidelines for gastrointestinal stromal tumors

Gastrointestinal stromal tumor (GIST) is the most common malignant neoplasm of mesenchymal origin. GIST spans a wide clinical spectrum that ranges from tumors with essentially no metastatic potential to malignant and life-threatening spread diseases. Gain-of-function mutations in KIT or PDGFRA receptor tyrosine kinases are the crucial drivers of most GISTs, responsible for tumor initiation and evolution throughout the entire course of the disease. The introduction of tyrosine kinase inhibitors targeting these receptors has substantially improved the outcomes in this formerly chemoresistant cancer. As of today, five agents hold regulatory approval for the treatment of GIST: imatinib, sunitinib, regorafenib, ripretinib, and avapritinib. This, in turn, represents a success for a rare neoplasm. During the past two decades, GIST has become a paradigmatic model in cancer for multidisciplinary work, given the disease-specific particularities regarding tumor biology and tumor evolution. Herein, we review currently available evidence for the management of GIST. This clinical practice guideline has been developed by a multidisciplinary expert panel (oncologist, pathologist, surgeon, molecular biologist, radiologist, and representative of patients' advocacy groups) from the Spanish Group for Sarcoma Research, and it is conceived to provide, from a critical perspective, the standard approach for diagnosis, treatment, and follow-up.

Development and validation of a prognostic nomogram for gastrointestinal stromal tumors in the postimatinib era: A study based on the SEER database and a Chinese cohort

BACKGROUND

After the standardization, recording and follow-up of imatinib use that significantly prolongs survival of gastrointestinal stromal tumors (GISTs), a comprehensive reassessment of the prognosis of GISTs is necessary and more conductive to treatment options.

METHODS

A total of 2185 GISTs between 2013 and 2016 were obtained from the Surveillance, Epidemiology, and End Results database and comprised our training (n = 1456) and internal validation cohorts (n = 729). The risk factors extracted from univariate and multivariate analyses were used to establish a predictive nomogram. The model was evaluated and tested in the validation cohort internally and in 159 patients with GIST diagnosed between January 2015 and June 2017 in Xijing Hospital externally.

RESULTS

The median OS was 49 months (range, 0-83 months) in the training cohort and 51 months (0-83 months) in the validation cohort. The concordance index (C-index) of the nomogram was 0.777 (95% CI, 0.752-0.802) and 0.7787 (0.7785, bootstrap corrected) in training and internal validation cohorts, respectively, and 0.7613 (0.7579, bootstrap corrected) in the external validation cohort. Receiver operating characteristic curves and calibration curves for 1-, 3-, and 5-year overall survival (OS) showed a high degree of discrimination and calibration. The area under the curve showed that the new model performed better than the TNM staging system. In addition, the model could be dynamically visualized on a webpage.

CONCLUSION

We developed a comprehensive survival prediction model for assessing the 1-, 3- and 5-year OS of patients with GIST in the postimatinib era. This predictive model outperforms the traditional TNM staging system and sheds light on the improvement of the prognostic prediction and the selection of treatment strategies for GISTs.

Anal canal gastrointestinal stromal tumour (GIST)

SummaryGastrointestinal stromal tumours (GISTs) are malignant mesenchymal tumours that originate from the interstitial pacemaker cells of Cajal. They are particularly rare, comprising only 5% of all GISTs, and often present at an advanced stage. Treatment for these tumours is still a topic of debate due to their low incidence and insidious location. A woman in her mid-70s presented with rectal bleeding and anal discomfort. A 4.5×4 cm anal GIST was diagnosed. A local excision was performed and the patient was further treated with tyrosine kinase inhibitors. At a 6-month follow-up, the MRI showed that she was disease free. Anorectal GISTs are unusual and tend to be aggressive. Surgical resection is the first-line treatment for primary, localised GISTs. However, the appropriate surgical technique for these tumours is still a topic of debate. Further studies are needed to fully understand the oncologic behaviour of these rare neoplasms.

Local recurrence in primary localized resected gastro-intestinal stromal tumors A registry observational national cohort study including 912 patients

BACKGROUND AND OBJECTIVES

Previous literature showed a high risk of recurrence following surgical treatment in patients with gastrointestinal stromal tumours (GISTs). However, little is known about the patient- and treatment characteristics of local recurrences (LRs) in GIST patients. Therefore, this study aimed to better understand patterns of LR in surgically treated localised GIST and to describe treatment options based on our Dutch GIST Registry (DGR).

METHODS

Data of primary surgically treated localised GIST between January 2009 until July 2021 were retrospectively retrieved from the DGR.

RESULTS

Of 1452 patients registered in the DGR, 912 patients were included in this study. Only 3.8% (35/912) of patients developed LR, including 20 patients with LR only and 15 patients with simultaneous LR and distant metastases (DM). Median time to LR was 30 (interquartile range 8-53) months from date of surgery. Eleven percent (100/912) of patients developed only DM. A total of 2.3% (6/259) of patients treated with adjuvant treatment developed an LR during adjuvant therapy. Seventy percent of patients with LR only (14/20) were treated with surgery (85.7% R0), which was mostly combined with systemic treatment.

CONCLUSIONS

Patients with primary surgically treated localised GIST have a limited risk of developing recurrence. Fifteen percent developed recurrence, of which one quarter developed an LR. Therefore, less intensified follow-up schedules could be considered, especially during treatment with adjuvant imatinib. In patients with LR only, potentially curative treatment strategies, including surgical (re-)resection, are often possible as treatment for LR.

The significance of margins in pediatric Non-Rhabdomyosarcoma soft tissue sarcomas: Consensus on surgical margin definition harmonization from the INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT)

BACKGROUND

Margin status following surgery in children, adolescents, and young adults with soft tissue sarcomas is controversial and has been defined differently by various specialties, with definitions changing over time and by cooperative group. The International Soft Tissue Sarcoma Consortium (INSTRuCT) is a collaboration of the Children's Oncology Group (COG) Soft Tissue Sarcoma Committee, European pediatric Soft Tissue sarcoma Study Group (EpSSG), and the European Cooperative Weichteilsarkom Studiengruppe (CWS) devoted to improving patient outcomes by pooling and mining cooperative group clinical trial data.

METHODS

The INSTRuCT non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) working group aimed to develop international harmonized recommendations regarding surgical margin assessment and definitions in children and adolescents with soft tissue tumors.

RESULTS AND CONCLUSION

This review addresses accepted principles and areas of controversy, including the perspectives of surgeons, pathologists, radiation oncologists, and pediatric oncologists, to develop a framework for building common guidelines for future research.

Effectiveness and safety of endoscopic resection for duodenal gastrointestinal stromal tumors: A single center analysis

BACKGROUND

Endoscopic resection for duodenal gastrointestinal stromal tumors (GISTs) is still considered a great challenge with a high risk of complications, including perforation, bleeding, tumor rupture, and residual tumor.

AIM

To assess the effectiveness and safety of endoscopic resection for duodenal GISTs.

METHODS

Between January 2010 and January 2022, 11 patients with duodenal GISTs were treated with endoscopic resection. Data were extracted for the incidence of complete resection, bleeding, perforation, postoperative infection, recurrence, and distant metastasis.

RESULTS

The incidence of successful complete resection of duodenal GISTs was 100%. Three cases (27.3%) had suspected positive margins, and the other 8 cases (72.7%) had negative vertical and horizontal margins. Perforation occurred in all 11 patients. The success rate of perforation closure was 100%, while 1 patient (9.1%) had suspected delayed perforation. All bleeding during the procedure was managed by endoscopic methods. One case (9.1%) had delayed bleeding. Postoperative infection occurred in 6 patients (54.5%), including 1 who developed septic shock and 1 who developed a right iliac fossa abscess. All 11 patients recovered and were discharged. The mean hospital stay was 15.3 d. During the follow-up period (14-80 mo), duodenal stenosis occurred in 1 case (9.1%), and no local recurrence or distant metastasis were detected.

CONCLUSION

Endoscopic resection for duodenal GISTs appears to be an effective and safe minimally invasive treatment when performed by an experienced endoscopist.

Prognostic Nomogram for Gastrointestinal Stromal Tumors after Surgery Based on the SEER Database

We aimed to determine prognostic factors and develop an effective and practical nomogram for predicting cancer-specific survival in gastrointestinal stromal tumor (GIST) patients. Postoperative data were obtained from the SEER database (2000-2018). Patients were divided into training and validation cohorts at random (7 : 3). Prognostic factors were screened, and a prognostic nomogram was established using log-rank testing and Cox regression. We used DCA, ROC curves, C-index, and calibration curves to evaluate our model's predictive performance. The clinical value of the nomogram and the modified National Institute of Health (M-NIH) classification were compared using the NRI and IDI. The Kaplan-Meier method was applied to examine survival by risk group, and log-rank tests were applied to compare variations in survival curves. Independent prognostic risk factors associated with cancer-specific survival on multivariate Cox proportional hazards regression analysis were age, race, and tumor location, size, grade, and stage. Clinically relevant variables need to be considered in addition to statistically significant variables when developing prognostic models to aid clinical decision-making. We included two additional variables (mitotic rate and chemotherapy) when constructing the prognostic model. The C-index was 0.766 (95% confidence interval (CI): 0.737-0.794) in the training cohort and 0.795 (95% CI: 0.754-0.836) in the internal validation group suggesting robustness. The areas under the ROC curve for three-year and five-year survival were >0.700, indicating satisfactory discrimination. The calibration curves showed good agreement between the predictions of the nomogram and the actual results. The NRI (0.346 for 3-year and 0.265 for 5-year cancer-specific survival for patients with GIST (GSS) prediction; validation cohort: 0.356 for 3-year and 0.246 for 5-year GSS prediction) and IDI values (0.047 for 3-year and 0.060 for 5-year GSS prediction; validation cohort: 0.071 for 3-year and 0.084 for 5-year GSS prediction) suggested that the established nomogram performed significantly better than the M-NIH classification. The DCA indicated that the nomogram was clinically useful and had a high discriminative ability in identifying patients who were at high risk of poor outcomes. According to nomogram findings, patients were divided into three groups (high, moderate, and low risk), with significantly different prognoses in both cohorts. Our nomogram satisfactorily predicted survival in postsurgical GIST patients, which may assist clinicians to evaluate the postoperative status and guide subsequent treatments.

Long-term prognosis of small gastric gastrointestinal stromal tumors with high histological grade: a longitudinal nested cohort study

BACKGROUND AND AIMS

Gastrointestinal stromal tumors (GIST) are mostly seen in the stomach. Clinical data on GISTs ≤ 2 cm with > 5 mitosis/50 HPFs are limited. This study aimed to analyze small GISTs with high histological grades to gain a more comprehensive understanding of their clinical characteristics with long-term follow-up.

METHODS

This was a nested cohort study of patients with gastric GISTs ≤ 2 cm and > 5 mitosis/50 HPFs. Individuals with endoscopically resected gastric specimens diagnosed as GISTs between January 2008 and July 2019 were enrolled. We analyzed baseline clinicopathological characteristics, perioperative characteristics, risk of recurrence, and metastasis during follow-up.

RESULTS

A total of 55 patients diagnosed with gastric GISTs ≤ 2 cm and > 5 mitosis/50 HPFs were enrolled. The mean tumor size was 1.6 ± 0.4 cm (median 1.7 cm, range 0.8-2.0 cm). ESD was performed in 33 patients (60.0%) and EFTR in 22 patients (40.0%). Mean mitotic figures were 8.9/50 HPFs. Postoperative bleeding in one patient (1.8%) was the only severe adverse event. The mean follow-up period was 61.2 ± 33.9 months (median 53 months, range 13-133 months). Five patients (5/55, 9.1%) received additional therapies, including partial gastrectomy and adjuvant Imatinib. Only two patients (2/55, 3.6%) showed signs of recurrence. We observed no significant difference regarding baseline clinical characteristics and recurrence among GISTs with mitosis < 10/50 HPF and ≥ 10/50 HPF. No patient had signs of metastasis during follow-up.

CONCLUSION

Endoscopic resection of gastric GISTs ≤ 2 cm with > 5 mitosis/50 HPFs has a low risk of recurrence and metastasis in the long term. Endoscopic resection of GISTs is safe and feasible.

Needle tract seeding and abdominal recurrence following pre-treatment biopsy of gastrointestinal stromal tumors (GIST): results of a systematic review

BACKGROUND

Gastrointestinal stromal tumors (GIST) are rare abdominal tumors. Pretreatment biopsies may be used to diagnose a GIST and enable tailored treatment. Some experts are skeptical about biopsies because they fear tumor cell seeding. The objective of this study was to determine if pretreatment biopsy is associated with increased tumor recurrence.

METHODS

We performed a systematic literature search and included studies assessing the oncological outcome of GIST patients who underwent a pre-treatment core needle biopsy or fine needle aspiration. We assessed methodological quality with the Newcastle-Ottawa-Scale for non-randomized studies. This review was registered in the PROSPERO database (CRD42021170290).

RESULTS

Three non-randomized studies and eight case reports comprising 350 patients were eligible for inclusion. No prospective study designed to answer the review question was found. One case of needle tract seeding after percutaneous core needle biopsy of GIST was reported. None of the studies reported an increased rate of abdominal recurrence in patients with pretreatment biopsy.

CONCLUSIONS

The existing evidence does not indicate a relevant risk of needle tract seeding or abdominal recurrence after pre-treatment biopsy of GIST. Biopsy can safely be done to differentiate GIST from other tumors and to select the most appropriate treatment.

Comparison of Prognosis Between Microscopically Positive and Negative Surgical Margins for Primary Gastrointestinal Stromal Tumors: A Systematic Review and Meta-Analysis

Background

This meta-analysis aimed to determine the prognostic impact of microscopically positive margins (R1) on primary gastrointestinal stromal tumors.

Methods

A literature search was performed using PubMed, Embase, Web of Science, and Cochrane Library for studies up to 23 November 2020. The pooled disease-free survival (DFS) and overall survival (OS) between R1 and negative margins (R0) were estimated using a random-effects model.

Results

Twenty studies with 6,465 patients were included. Compared with R0 resection, R1 was associated with poor DFS in patients who did not receive adjuvant Imatinib (HR: 1.62, 95% CI: 1.26-2.09; P = 0.48, I² = 0%; reference: R0). This negative impact of R1 disappeared with the use of adjuvant Imatinib (HR: 1.23, 95% CI: 0.95-1.60; P = 0.38, I2 = 6%; reference: R0). R1 was related to poor DFS in gastric GISTs (HR: 2.15, 95% CI: 1.15-5.02, I² = 0%; reference: R0), which was attenuated in the subgroup of adjuvant Imatinib (HR: 2.24, 95% CI: 0.32-15.60; P = 0.84, I² = 0%; reference: R0). Rectal GIST with R1 margin who even received adjuvant Imatinib still had poor DFS (HR: 3.79, 95% CI: 1.27-11.31; P = 0.54, I² = 0%; reference: R0). Patients who underwent R1 resection had similar OS compared with those underwent R0 resection regardless of the use of adjuvant Imatinib.

Conclusion

R1 was associated with poor DFS for primary GISTs, which was attenuated by adjuvant therapy with Imatinib. Similar result was observed in the gastric GISTs subgroup. Rectal GIST patients with R1 resection had poor DFS even when they received adjuvant Imatinib. The R1 margin did not influence the OS of GISTs.

Comparison Among Endoscopic, Laparoscopic, and Open Resection for Relatively Small Gastric Gastrointestinal Stromal Tumors (<5 cm): A Bayesian Network Meta-Analysis

Background

Endoscopic resection (ESR) is a novel minimally invasive procedure for superficial tumors. Its safety, efficiency, and outcome for gastric gastrointestinal stromal tumors (gGISTs) less than 5 cm remains unclear compared to laparoscopic resection (LAR) and open resection (ONR). The current network meta-analysis aimed to review and analyze the available evidence of this question.

Methods

PubMed, Embase, Cochrane Library, and Web of Science databases were searched to identify eligible studies published up to July 6, 2020. The perioperative and long-term oncological outcomes among ESR, LAR, and ONR for gGIST (<5 cm) were estimated through the Bayesian network meta-analysis with a random-effect model.

Results

Fifteen studies with 1,631 patients were included. ESR was associated with a shorter operative time [mean difference, MD: -36; 95% confidence interval, CI (-55, -16)], a higher rate of positive margin [odds ratio, OR: 5.1 × 10¹⁰, 95% CI (33, 2.5 × 10³²)], and less costs [MD: -1 × 10⁴, 95% CI (-1.6 × 10⁴, -4.4 × 10³)] but similar time to resume flatus [MD: 0.52, 95% CI (-0.16, 1.1)] and diet [MD: -3.5, 95% CI (-5.6, -1.6)] compared to LAR. A higher rate of total complications [OR: 11, 95% CI (1.2, 140)] was observed in patients who received ESR compared to patients who received LAR. After excluding perforation from the total complication category, the difference of complication between ESR and LAR disappeared [OR: 0.87, 95% CI (0.22, 2.3)]. The recurrence rate [OR: 1.3, 95% CI (0.40, 4.5)] and disease-free survival [hazard ratio: 1.26, 95% CI (0.60, 2.63)] showed no significant difference between ESR and LAR. ESR was associated with better or equivalent perioperative and long-term outcomes compared to ONR, except for positive margin. A subgroup analysis (<2 and 2–5 cm) showed no significantly different results among these three procedures either.

Conclusion

ESR was shown to be a safe and efficient alternative procedure to both LAR and ONR for gGISTs less than 2 cm and within 2–5 cm, respectively, without worsening the oncologic outcomes. However, preoperative assessment of tumor site is of importance for the determination of procedures regarding the increased incidence of a positive margin related to ESR.

Clinicopathological features, clinical efficacy on 101 cases of rectal gastrointestinal stromal tumors, and the significance of neoadjuvant therapy

Objective

To investigate the clinicopathological features and clinical efficacy among 101 cases of rectal gastrointestinal stromal tumors (GISTs) and to investigate the significance of imatinib mesylate (IM) neoadjuvant therapy.

Methods

The clinicopathological features, treatment methods, perioperative data, and prognosis of the patients were summarized and analysed in 101 patients with rectal GISTs who received treatment in the Gastrointestinal Surgery of West China Hospital of Sichuan University and the Affiliated Hospital of Guizhou Medical University from August 2002 to November 2020 in China.

Results

A total of 101 patients, including 64 males and 37 females, were aged from 22 to 79 years (55.4 ± 12.2 years). Among the 70 patients who underwent direct surgery, 8 were very low risk cases, 10 were low risk cases, 7 were intermediate risk cases, and 45 were high risk cases. Cox regression analysis showed that postoperative IM adjuvant treatment improved the disease-free survival (DFS) and overall survival (OS) of 52 intermediate and high risk patients. Among the 31 patients who received neoadjuvant therapy, the objective response rate (ORR) was 83.9% (26/31), and the disease control rate (DCR) reached 96.8% (30/31). Subgroup analysis was also conducted based on the tumour diameter. (1) Among the 36 patients with a diameter ≤ 5 cm, two patients received IM neoadjuvant therapy, while 34 patients received direct surgery. Neither univariate nor Cox regression analysis found that neoadjuvant therapy affected DFS and OS. (2) Among the 65 patients with a diameter > 5 cm, 29 received IM neoadjuvant therapy, and 36 received direct surgery. Patients who underwent neoadjuvant therapy had less blood loss (P = 0.022), shorter postoperative hospital stay (P = 0.001), increased anal retention rate (93.1% vs. 72.2%, P = 0.031), and decreased enterostomy rate (10.3% vs. 33.3%, P = 0.037) than those who underwent direct surgery. Cox regression analysis suggested that neoadjuvant therapy and postoperative IM adjuvant therapy improved DFS.

Conclusion

Rectal GISTs are relatively rare and highly malignant tumors. Postoperative oral IM therapy can improve the DFS and OS of intermediate and high risk patients. In patients with rectal GISTs with diameters > 5 cm, IM neoadjuvant therapy can improve anal retention rate, preserve the structure and function of the organs, reduce enterostomy rate, and improve prognosis.

Dynamic survival analysis of gastrointestinal stromal tumors (GISTs): a 10-year follow-up based on conditional survival

Background

The prognosis of patients with gastrointestinal stromal tumors (GISTs) is generally evaluated at the time of diagnosis but does not reflect the survival dynamics of patients in the future. Therefore, the purpose of this article was to evaluate the conditional survival (CS) of Chinese patients with GISTs after radical resection.

Methods

This retrospective study included 451 patients who underwent radical surgery for GISTs. A Cox proportional hazard model was used to evaluate the prognostic factors of disease-free survival (DFS). The 3-year conditional DFS (CDFS₃) of patients who survived for x years was expressed as CDFS₃₌DFS_(x + 3)/DFS_(x).

Results

The traditional 3-year DFS rate decreased gradually from 94.0% at 3 years to 77.3% at 7 years, while the CDFS₃ rate increased from 94.0 to 95.2% over the survival time of the patients. In addition, classic clinicopathological prognostic factors had different effects on CDFS_3, with changes observed in survival time, but these effects were only slight or moderate (|d|<0.5). Although multivariate analysis showed that age, sex, mitotic index and tumor rupture were independent risk factors for DFS at baseline, all adverse prognostic factors, except for the mitotic index, lost their predictive significance at 5 years after operation. When the Modified NIH criteria were included, the risk staging was found to be an independent risk factor for recurrence or death. Time-dependent Cox regression analysis showed that the modified NIH criteria independently affected the recurrence or death of GIST patients within 2 years after operation.

Conclusion

CS provides detailed dynamic survival information about Chinese patients with primary resected GISTs. The mitotic index is of great clinical significance for the monitoring and follow-up of patient populations with a high risk of tumor recurrence or death until 5 years after surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08828-y.

Humeral metastasis as the only recurrence of a 5-year resected gastrointestinal stromal tumor: a case report

INTRODUCTION

Gastrointestinal stromal tumors represent the most frequently encountered primary mesenchymal tumors. Whereas the liver and the peritoneum are known to be the preferential metastasis sites, no therapeutic standard has yet been established for the management of bone metastases because of their very low incidence. We report a unique example of a single humerus metastasis of a jejunal gastrointestinal stromal tumor.

CASE PRESENTATION

We report the case of a 72-year-old European woman whose jejunal gastrointestinal stromal tumor was resected in 2013 and treated during the following 3 years with imatinib (400 mg daily). In 2018, she developed a single humeral bone lesion that was identified as a gastrointestinal stromal tumor metastasis. After 7 months of imatinib intake, reconstructive surgery was performed. Pathologists confirmed the satisfactory histological regression and assessed the complete tumor resection. The patient is still on imatinib maintenance therapy, with no recurrence reported so far. She fully recovered the upper limb function after following an appropriate rehabilitation program.

DISCUSSION

Current literature and published case reports indicate that bones are one of the rarest locations of gastrointestinal stromal tumor metastasis (about 1%), with occurrence mainly in the spine. Patients initially diagnosed with gastrointestinal stromal tumor of the small intestine and stomach are more likely to suffer from bone metastasis, compared with other gastrointestinal stromal tumor locations. The median overall survival rate is higher for patients with isolated bone metastasis compared with those having liver metastasis. Metastasis occurs on average 4 years after the primary, but it may take up to 20 years, emphasizing the need for long-term clinical and radiological monitoring. Although specific guidelines for such cases have not yet been established, we suggest that a multimodal concerted approach involving surgery or radiotherapy associated with tyrosine kinase inhibitor intake should be considered.

CONCLUSION

Bones are one of the rarest locations of gastrointestinal stromal tumor metastasis. A multidisciplinary collaboration was set up to allow conservative surgery of our patient after several months of imatinib treatment. A year and a half later, the patient is still in complete remission. This specific case supports the concept of an intermediate stage between local and oligometastatic disease that should be managed with a curative aim, as much as possible.

The Combination of Neoadjuvant Therapy and Surgical Resection: A Safe and Effective Treatment for Rectal Gastrointestinal Stromal Tumors

Background

Rectal gastrointestinal stromal tumors (GISTs) are rare digestive tumors. The treatment methods of rectal GISTs are diverse, while no standardized treatment was recommended. The aim of this study was to report the treatment mode of rectal GISTs in our center.

Methods

Patients with pathologically confirmed rectal GISTs who received neoadjuvant therapy and surgical resection were retrospectively collected. Perioperative complications and long-term prognosis were evaluated.

Results

From January 2010 to December 2019, 36 patients were pathologically diagnosed with primary rectal GISTs. After excluding patients who were treated with surgery or imatinib alone, 21 patients received neoadjuvant therapy and surgery was enrolled. During neoadjuvant treatment, tumors shrank significantly (6.53cm to 4.68cm, p<0.001) without toxicities over grade 2. The total postoperative complication rate was 42.9% (all grade). R0 resection was achieved in 76.2% patients. Transanal resection had advantages on anus preservation and postoperative recovery. No patients died during the follow-up period, 4 patients relapsed and the relapse-free survival was 81.0%.

Conclusion

The combination of neoadjuvant therapy and surgical resection was a safe and effective treatment for rectal gastrointestinal stromal tumors.

Gastrointestinal stromal tumours

Gastrointestinal stromal tumours (GIST) have an incidence of ~1.2 per 10⁵ individuals per year in most countries. Around 80% of GIST have varying molecular changes, predominantly mutually exclusive activating KIT or PDGFRA mutations, but other, rare subtypes also exist. Localized GIST are curable, and surgery is their standard treatment. Risk factors for relapse are tumour size, mitotic index, non-gastric site and tumour rupture. Patients with GIST with KIT or PDGFRA mutations sensitive to the tyrosine kinase inhibitor (TKI) imatinib that are at high risk of relapse have improved survival with adjuvant imatinib treatment. In advanced disease, median overall survival has improved from 18 months to >70 months since the introduction of TKIs. The role of surgery in the advanced setting remains unclear. Resistance to TKIs arise mainly from subclonal selection of cells with resistance mutations in KIT or PDGFRA when they are the primary drivers. Advanced resistant GIST respond to second-line sunitinib and third-line regorafenib, as well as to the new broad-spectrum TKI ripretinib. Rare molecular forms of GIST with alterations involving NF1, SDH genes, BRAF or NTRK genes generally show primary resistance to standard TKIs, but some respond to specific inhibitors of the activated genes. Despite major advances, many questions in both advanced and localized disease remain unanswered.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Final analysis of the randomized trial on imatinib as an adjuvant in localized gastrointestinal stromal tumors (GIST) from the EORTC Soft Tissue and Bone Sarcoma Group (STBSG), the Australasian Gastro-Intestinal Trials Group (AGITG), UNICANCER, French Sarcoma Group (FSG), Italian Sarcoma Group (ISG), and Spanish Group for Research on Sarcomas (GEIS)☆

BACKGROUND

In 2004, we started an intergroup randomized trial of adjuvant imatinib versus no further therapy after R0-R1 surgery in localized, high/intermediate-risk gastrointestinal stromal tumors (GIST) patients. Interim analysis results were published in 2015 upon recommendation from an independent data review committee. We report the final outcome of the study.

PATIENTS AND METHODS

This was a randomized, open-label, multicenter phase III trial carried out at 112 hospitals in 12 countries. Patients were randomized to 2 years of imatinib, 400 mg daily, or no further therapy after surgery. The primary endpoint was imatinib failure-free survival (IFFS), while relapse-free survival (RFS), relapse-free interval (RFI), overall survival (OS) and toxicity were secondary endpoints. Adjusting for the interim analyses, results on IFFS were assessed on a 4.3% significance level; for the other endpoints, 5% was used.

RESULTS

Nine hundred and eight patients were randomized between January 2005 and October 2008: 454 to imatinib and 454 to observation; 835 patients were eligible. With a median follow-up of 9.1 years, 5 (10)-year IFFS was 87% (75%) in the imatinib arm versus 83% (74%) in the control arm [hazard ratio (HR) = 0.87, 95.7% confidence interval (CI) (0.65; 1.15), P = 0.31]; RFS was 70% versus 63% at 5 years and 63% versus 61% at 10 years, [HR = 0.71, 95% CI (0.57; 0.89), P = 0.002]; OS was 93% versus 92% at 5 years and 80% versus 78% at 10 years [HR = 0.88, 95% CI (0.65; 1.21), P = 0.43]. Among 526 patients with high-risk GIST by local pathology, 10-year IFFS and RFS were 69% versus 61%, and 48% versus 43%, respectively.

CONCLUSIONS

With 9.1 years of follow-up, a trend toward better long-term IFFS in imatinib-treated patients was observed in the high-risk subgroup. Although the difference was not statistically significant and the surrogacy value of such an endpoint is not validated, this may be seen as supporting the results reported by the Scandinavian/German trial, showing a sustained small but significant long-term OS benefit in high-risk GIST patients treated with 3 years of adjuvant imatinib.

Positive microscopic surgical margins: Is there an association with survival in resected small gastrointestinal stromal tumors?

BACKGROUND

Few studies evaluate the relationships between surgical approach, histologic margin, and overall survival in gastrointestinal stromal tumor. We test the hypothesis that margin positive resection is associated with compromised overall survival.

METHODS

We queried the National Cancer Data Base to identify patients undergoing resections for gastrointestinal stromal tumors ≤3 cm in size between 2010 and 2015. Multivariable logistic regression was used to identify factors associated with positive microscopic margins on final pathology. Cox proportional hazard methods were used to evaluate factors associated with overall survival.

RESULTS

2064 patients met inclusion criteria; 135 (6.5%) had a microscopically positive surgical margin. On multivariable regression, minimally invasive approach was not associated with risk of a positive margin (OR 1.06 95% CI [0.71, 1.59]). On Cox analysis, positive margin status was not associated with OS (R1: 1.03, CI [0.46-2.31], reference R0).

CONCLUSIONS

Positive microscopic surgical margins are not associated with compromised overall survival in patients undergoing resection of small gastrointestinal stromal tumors. Minimally invasive surgical approaches do not compromise oncologic outcomes in these cases.

Do microscopic surgical margins matter for primary gastric gastrointestinal stromal tumor?

BACKGROUND

Although tumor size and mitotic rate are established prognostic factors for worse survival in patients undergoing surgical resection for gastric gastrointestinal stromal tumors, the impact of microscopic margins, or R1 resection, is not completely established.

METHODS

Patients who received no neoadjuvant therapy and underwent surgical resection for stage I to III gastric gastrointestinal stromal tumors were identified from the 2010 to 2013 National Cancer Database and divided into 2 cohorts, R0 and R1 resections. Cox proportional hazards ratio and Kaplan Meier survival estimates were utilized to analyze 5-y overall survival.

RESULTS

Of 2,084 patients, those with R1 resection (57, 2.7%) were more likely to have tumors >10 cm (28.1% vs 11.9%, odds ratio 3.51, P = .017) and stage III disease (26.3% vs 11.2%, odds ratio 2.26, P = .047). Although margin status was associated with higher risk tumors, it was not associated with receipt of adjuvant therapy. After multivariate Cox regression, R1 and R0 patients did not have a difference in 5-y overall survival (82.5% vs 88.6%, hazards ratio 1.26, P = .49). When stratified by stage of disease, there remained no difference in survival across all stages when comparing R1 and R0 patients.

CONCLUSION

Positive microscopic margins are uncommon but do not appear to impact survival outcomes in patients with resected localized gastric gastrointestinal stromal tumors.