Sarcopenia as a novel prognostic factor in the patients of primary localized gastrointestinal stromal tumor.

BACKGROUND: Sarcopenia predicts poor prognosis of a variety of gastrointestinal malignancies. However, there is a lack of study on the association between skeletal muscle index (SMI) and the prognosis of gastrointestinal stromal tumor (GIST). The aim of this study is to develop a novel nomogram based on sarcopenia for GIST patients to predict overall survival (OS). METHODS: SMI was measured by computed tomography scan of 107 patients who underwent resection for primary localized gastrointestinal stromal tumor (GIST). Sarcopenia was defined by cutoff values for SMI as 40.1 cm2/m2 and 39.8 cm2/m2 using optimum stratification for males and females respectively. Factors were included in the nomogram were specified by univariate and multiple Cox proportional hazard analysis. Concordance index (C-index) and calibration curves were conducted to measure the discrimination and accuracy of the nomogram. The utility of the nomogram was assessed by the decision curve analysis (DCA). RESULTS: Twenty-eight (26.2%) of 107 patients were sarcopenic. Sarcopenia was correlated significantly with body mass index, albumin, female sex, resection style, mitotic index, rupture status, survival. Sarcopenia was significantly related to decreased overall survival (p = 0.003).The nomogram including sarcopenia status, resection style and mitotic index had an excellent discrimination with C-index 0.794. The calibration curves represented a good accordance between the actual observation and nomogram prediction for overall survival. Decision curve analysis illustrated that the nomogram was helpful in clinic. CONCLUSIONS: We developed a nomogram based on sarcopenia to predict overall survival after resection of GISTs which is an effective and favorable prognostication tool.

Down-regulation of SOCS6: an unfavorable prognostic factor for gastrointestinal stromal tumor proven by survival analysis.

BACKGROUND: Many studies reporting that down-regulation of SOCS6 plays vital roles in promoting progression of malignant tumors have been published. The present study was performed to evaluate whether SOCS6 was significantly associated with prognosis of GIST patients. METHODS: Immunohistochemical staining was accomplished to evaluate the expression levels of SOCS6 among GIST patients. The impacts of SOCS6 expression on overall survival (OS) and recurrence-free survival (RFS) of GIST patients were assessed by Cox proportional hazard regression model analysis and Kaplan-Meier curve analysis. RESULTS: It was demonstrated that the expression level of SOCS6 was significantly associated with tumor size (P=0.001). Then according to Kaplan-Meier curve analysis, low expression of SOCS6 was significantly correlated with worse OS and RFS of GIST patients. Ultimately, it was revealed by Cox proportional regression model analysis that low expression of SOCS6 was an independent predictive factor for OS and RFS. CONCLUSIONS: Low expression of SOCS6 was an independent prognostic factor for GIST, suggesting its potential as a novel biomarker predicting survival of GIST patients.

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 CDFS3, 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.

A Retrospective Study of Postoperative Outcomes in 98 Patients Diagnosed with Gastrointestinal Stromal Tumor (GIST) of the Upper, Middle, and Lower Gastrointestinal Tract Between 2009 and 2019 at a Single Center in Poland.

BACKGROUND Gastrointestinal stromal tumors (GISTs) arise in the smooth muscle pacemaker interstitial cells of Cajal, or similar cells. The aim of this retrospective study between 2009 and 2019 from a single center in Poland was to assess the selected prognostic factors (location, tumor size, mitotic index, body mass index (BMI), length of hospital stay, age, sex, and coexistent neoplasm) and to investigate postoperative outcomes in 98 patients with GIST of the upper, middle, and lower gastrointestinal tract. MATERIAL AND METHODS Between 2009 and 2019, 98 patients (50 women and 48 men) with an average age of 63.8 years (range from 38 to 90 years) were operated on for GIST in the Department of Gastrointestinal Surgery in Katowice, Poland. Based on the intraoperative and postoperative investigations, the tumor size and mitotic index were determined in each case. RESULTS A statistically significant correlation between age and mitotic index (MI) was found (p=0.02). The higher the MI, the younger the age of the patients. However, regardless of sex, younger patients had a tendency to survive longer. A >60-year-old male patient's probability of survival was around 65% after 40 months. Higher mitotic index was also associated with larger tumor size (p<0.0001). Female patients had a tendency to survive longer than males. CONCLUSIONS The findings from this small retrospective study support the importance of preoperative evaluation and frequent postoperative follow-up for patients with GIST of the gastrointestinal tract, particularly in older male patients, and patients with malignant comorbidities, which are associated with increased mortality.

Expression of fatty acid-binding protein-4 in gastrointestinal stromal tumors and its significance for prognosis.

BACKGROUND: Fatty acid-binding proteins (FABPs) have been found to be involved in tumorigenesis and development. However, the role of FABP4, a member of the FABPs, in GISTs (Gastrointestinal stromal tumors) remains unclear. This study aimed to investigate the expression of FABP4 and its prognostic value in GISTs. METHODS: FABP4 expression in 125 patients with GISTs was evaluated by immunohistochemical analysis of tissue microarrays. The relationship between FABP4 expression and clinicopathological features and prognosis of GISTs was analyzed. RESULTS: Multiple logistic regression analysis showed that expression of FABP4 correlated with tumor size and mitotic index. Furthermore, FABP4 level, tumor size, mitotic index, and high AFIP-Miettinen risk were independent prognostic factors in GISTs. The Kaplan-Meier survival curve showed that the 5-year survival rate of patients with high-FABP4 expression GISTs was lower. CONCLUSIONS: These results suggested that high-FABP4 expression might be a marker of malignant phenotype of GISTs and poor prognosis.

Avapritinib Versus Regorafenib in Locally Advanced Unresectable or Metastatic GI Stromal Tumor: A Randomized, Open-Label Phase III Study.

PURPOSE: Primary or secondary mutations in KIT or platelet-derived growth factor receptor alpha (PDGFRA) underlie tyrosine kinase inhibitor resistance in most GI stromal tumors (GISTs). Avapritinib selectively and potently inhibits KIT- and PDGFRA-mutant kinases. In the phase I NAVIGATOR study (NCT02508532), avapritinib showed clinical activity against PDGFRA D842V-mutant and later-line KIT-mutant GIST. VOYAGER (NCT03465722), a phase III study, evaluated efficacy and safety of avapritinib versus regorafenib as third-line or later treatment in patients with unresectable or metastatic GIST. PATIENTS AND METHODS: VOYAGER randomly assigned patients 1:1 to avapritinib 300 mg once daily (4 weeks continuously) or regorafenib 160 mg once daily (3 weeks on and 1 week off). Primary end point was progression-free survival (PFS) by central radiology per RECIST version 1.1 modified for GIST. Secondary end points included objective response rate, overall survival, safety, disease control rate, and duration of response. Regorafenib to avapritinib crossover was permitted upon centrally confirmed disease progression. RESULTS: Four hundred seventy-six patients were randomly assigned (avapritinib, n = 240; regorafenib, n = 236). Median PFS was not statistically different between avapritinib and regorafenib (hazard ratio, 1.25; 95% CI, 0.99 to 1.57; 4.2 v 5.6 months; P = .055). Overall survival data were immature at cutoff. Objective response rates were 17.1% and 7.2%, with durations of responses of 7.6 and 9.4 months for avapritinib and regorafenib; disease control rates were 41.7% (95% CI, 35.4 to 48.2) and 46.2% (95% CI, 39.7 to 52.8). Treatment-related adverse events (any grade, grade ≥ 3) were similar for avapritinib (92.5% and 55.2%) and regorafenib (96.2% and 57.7%). CONCLUSION: Primary end point was not met. There was no significant difference in median PFS between avapritinib and regorafenib in patients with molecularly unselected, late-line GIST.

Ripretinib intrapatient dose escalation after disease progression provides clinically meaningful outcomes in advanced gastrointestinal stromal tumour.

PURPOSE: Ripretinib is a switch-control tyrosine kinase inhibitor that broadly inhibits KIT and platelet-derived growth factor receptor α kinase signalling. Ripretinib showed preliminary efficacy in patients with advanced gastrointestinal stromal tumour (GIST) in a phase I study across a range of doses. Results were confirmed in the phase III INVICTUS study, and ripretinib 150 mg once daily (QD) was subsequently approved as a ≥fourth-line therapy. Here, we report the phase I study results of intrapatient dose escalation (IPDE) in patients with GIST treated across second, third and later lines of therapy. METHODS: Patients with advanced GIST who experienced disease progression (PD) at ripretinib 150 mg QD could dose escalate to 150 mg twice daily (BID). Progression-free survival (PFS) 1 was calculated from the date of the first dose of ripretinib 150 mg QD to PD (as per Response Evaluation Criteria in Solid Tumours 1.1); PFS2 was from the date of IPDE (150 mg BID) to PD or death. Treatment-emergent adverse events (TEAEs) were summarised by dosing periods and compared descriptively. RESULTS: Of 142 patients with GIST receiving ripretinib 150 mg QD, 67 underwent IPDE. IPDE provided benefit across all lines of therapy; the median PFS2 was 5.6, 3.3 and 4.6 months for patients on second-, third- and ≥fourth-line therapy, respectively. A partial metabolic response after IPDE was demonstrated in 13 of 37 patients with available positron emission tomography scans. TEAEs reported at both doses were similar. CONCLUSION: Ripretinib IPDE after PD provided continued clinical benefit in advanced GIST across second, third and later lines of therapy with a similar safety profile to that observed with the QD regimen.

Clinicopathological Features and Outcomes of Gastrointestinal Stromal Tumours in Oman: A multi-centre study.

OBJECTIVES: This study aimed to report the clinicopathological features, management and long-term outcomes of patients with gastrointestinal stromal tumours (GISTs) in Oman. METHODS: This retrospective study was conducted on patients treated for GIST between January 2003 and December 2017 at three tertiary referral centres in Muscat, Oman. All patients with confirmed histopathological diagnoses of GIST and followed-up at the centres during this period were included. Relevant information was retrieved from hospital records until April 2019. RESULTS: A total of 44 patients were included in the study. The median age was 55.5 years and 56.8% were female. The most common primary site of disease was the stomach (63.6%) followed by the jejunum/ileum (18.2%). Two patients (4.5%) had c-Kit-negative, discovered on GIST-1-positive disease. A total of 24 patients (54.5%) presented with localised disease and eight (33.3%) were classified as being at high risk of relapse. Patients with metastatic disease received imatinib in a palliative setting, whereas those with completely resected disease in the intermediate and high-risk groups were treated with adjuvant imatinib. Of the six patients (13.6%) with progressive metastatic disease, of which four had mutations on exon 11 and one on exon 9, while one had wild-type disease. Overall, rates of progression-free survival and overall survival (OS) at 100 months were 77.4% and 80.4%, respectively. Rates of OS for patients with localised and metastatic disease were 89.9% and 80.2%, respectively. CONCLUSION: The presenting features and outcomes of patients with GISTs in Oman were comparable to those reported in the regional and international literature.

Prognostic Value of Bleeding in Gastrointestinal Stromal Tumors: A Meta-Analysis.

BACKGROUND: Gastrointestinal bleeding is the most common clinical manifestation of gastrointestinal stromal tumor. It is of great significance to the prognosis of patients. But the results are controversial. The purpose of this study was to evaluate the relationship between gastrointestinal bleeding and clinical prognosis in patients with GIST. METHODS: A systematic literature search was performed in Pumbed, Cochrane Library, EMBASE, ClinicalTrials.gov, CNKI, VIP and wanfang databases with the pattern of unlimited languages. 12 studies with 2781 individuals were included in the final analysis. The overall survival (OS), recurrence-free survival/disease-free survival (RFS/DFS) and related factors affecting bleeding in patients with gastrointestinal stromal tumor (GIST) were extracted. Hazard ratio (HR) and 95% confidence interval (CI) were used for in the meta-analysis. RESULTS: A total of 12 articles were included in the study, including 2781 patients with GIST, including 845 patients with gastrointestinal bleeding. The OS of GIST patients with gastrointestinal bleeding was significantly worse (HR = 2.54, 95% CI = 1.13-5.73, P = 0.025). But there was no significant difference in RFS between gastrointestinal bleeding patients and non-bleeding patients (HR = 1.35, 95% CI = 0.70-2.61, P = 0.371). Further analysis of the related factors of GI bleeding in GIST patients was observed, besides the aging factor (HR = 1.02, 95% CI = 0.69-1.50, P = 0.929), Small intestinal stromal tumor (HR = 0.56, 95% CI = 0.41-0.76, P < 0.001), tumor diameter ≥ 5 cm (HR = 2.09, 95% CI = 1.20-3.63, P = 0.009), Mitotic index ≥ 5/50 HPF (HR = 1.66, 95% CI = 1.11-2.49, P = 0.014) and tumor rupture (HR = 2.04, 95% CI = 1.0-3.82, P = 0.026) all increased the risk of GI bleeding in patients with GIST. CONCLUSIONS: The OS of GIST patients with GI bleeding was worse than non-GI bleeding, but had no significant effect on RFS. Nevertheless the aging factor, the location of GIST in the small intestine, tumor diameter ≥ 5 cm, Mitotic index ≥ 5/50 HPF and tumor rupture all increased the risk of GI bleeding in patients with GIST.

The effect of neoadjuvant imatinib therapy on outcome and survival in rectal gastrointestinal stromal tumors: A multiinstitutional study.

BACKGROUND AND OBJECTIVES: This study aimed to characterize the efficacy of neoadjuvant imatinib in rectal gastrointestinal stromal tumors (GISTs) and the prognostic characteristics of patients after surgery. METHODS: Patients with rectal GISTs who received neoadjuvant imatinib between 2000 and 2019 were selected from 11 large-scale tertiary hospitals in China. The best response to neoadjuvant imatinib was assessed. Propensity score matching (PSM) was conducted to reduce confounders. Recurrence free survival (RFS) and overall survival (OS) were estimated using Kaplan-Meier method. RESULTS: Of the 100 patients, 75, 18, and 7 had a partial response (PR), stable disease (SD), and progressive disease (PD), respectively. The median tumor size decreased from 5 cm before treatment to 4 cm after treatment (p < 0.001). A total of 31 patients underwent genetic testing after surgery; 23 of patients with exon 11 mutation had PR and 2 had SD. One of the patients with exon 9 mutation had PR, 2 had SD, and 1 had PD. Two patients with the wild type GIST had PD. A total of 86 patients underwent surgery of which 85 underwent complete resection; 72 underwent anal preservation and 40 underwent local excision (LE). After PSM, patients who received neoadjuvant therapy had higher rates of LE (p = 0.001) and anal preservation (p = 0.033) than those of patients without neoadjuvant therapy. The median follow-up time was 37 months. Nine patients experienced recurrence and one patient died. The 3-year RFS and OS rates were 95.0% and 100%, respectively. After PSM, we found that there was no significant difference in RFS between patients who received or did not receive neoadjuvant therapy (p = 0.623). Univariate analysis showed postneoadjuvant tumor size (p = 0.469) and mitotic count (p = 0.294) were not associated with the RFS in patients who received neoadjuvant imatinib. CONCLUSIONS: Neoadjuvant imatinib can shrink rectal GIST size, increasing the possibility of complete resection and anal preservation. Further studies are warranted to understand the long-term outcomes of rectal GISTs in patients receiving neoadjuvant imatinib.

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

Backgroung Gastrointestinal stromal tumours (GISTs) located in the jejunum or ileum (JI-GIST) are considered worse prognosis compared to those of gastric (G-GIST) location. It has been suggested that this dogma should be revised. The aim of this study was to describe the characteristics of jejunoileal GISTs and its prognosis and to compare them with G-GISTs in the era of imatinib. Methods We retrospectively reviewed the clinical histories of all the patients diagnosed with GISTs between January 2000 and November 2016: Clinical and pathological data, as recurrence, metastatic state, disease-free survival (DFS) as well as overall survival (OS) rates of patients were reviewed. Results JI-GIST patients comprise 29 cases (37.7%). Compared to G-GIST, JI-GIST patients had undergone emergency surgery more frequently (37.9% vs. 10.4%, p = 0.007). According to the NIH-Fletcher classification, the low or very-low risk group represents 17.2% of JI-GISTs as opposed to 37.6% of G-GISTs (p < 0.005). When the AFIP-Miettinen system was used the low or very-low group represented 17.2% of JI-GISTs vs. 58.4% in the G-GISTs group (p < 0.001). Both local recurrence (24.1% vs. 12.5%, p < 0.05) and metastatic rate (34.5% vs. 22.9%, p < 0.05) were higher in the JI-GIST group than in G-GIST. 5- and 10-year DFS and 10-year OS rate were lower for JI-GIST (54.5% and 39.6% vs. 77.2% and 60.8%, and 57.9% vs. 65%, respectively, p < 0.05). Conclusions The observed differences between both groups in DFS and OS rates at long term could be attributed to the effect of imatinib (AU)

Clinical efficacy comparison of avapritinib with other tyrosine kinase inhibitors in gastrointestinal stromal tumors with PDGFRA D842V mutation: a retrospective analysis of clinical trial and real-world data.

BACKGROUND: Avapritinib, a potent inhibitor of KIT and platelet-derived growth factor receptor A (PDGFRA) tyrosine kinases, has demonstrated unprecedented clinical activity in PDGFRA D842V-mutant gastrointestinal stromal tumors (GIST). METHODS: This retrospective analysis compared efficacy of avapritinib in patients enrolled in the NAVIGATOR phase 1 trial (NCT02508532) with the efficacy of other tyrosine kinase inhibitors (TKIs) in patients with unresectable/metastatic PDGFRA D842V-mutant GIST enrolled in a retrospective natural history study (Study 1002). The primary endpoint was overall survival (OS) from the start of reference treatment (avapritinib for NAVIGATOR patients or first-line TKI for treatment of unresectable/metastatic GIST for Study 1002 patients); the secondary endpoint was progression-free survival (PFS). Adjusted Kaplan-Meier survival curves were compared by Cox regression. RESULTS: Fifty-six (NAVIGATOR) and 19 (Study 1002) patients with PDGFRA D842V-mutant GIST were evaluated; of the 56 patients from NAVIGATOR, a subgroup of patients treated with either 300 mg (recommended phase 2 dose) or 400 mg (maximum tolerated dose) avapritinib starting dose (n = 38) were analyzed separately. Patient characteristics were adjusted for imbalances by propensity score between the study groups. Inverse probability of treatment weighting-adjusted Kaplan-Meier analysis of OS showed median OS was not reached for NAVIGATOR patients treated with any of the avapritinib doses tested and was 12.6 months for Study 1002 patients; OS rate at 6/48 months was 100%/63% in NAVIGATOR and 56%/17% in Study 1002 (P = 0.0001). In the 300/400 mg subgroup, adjusted OS rates at 6/36 months were 100%/73 and 68%/20% in Study 1002 (P = 0.0016). Adjusted median PFS was 29.5 months in NAVIGATOR and 3.4 months in Study 1002. CONCLUSIONS: In this indirect, retrospective analysis, avapritinib demonstrated more durable survival outcomes compared with other TKIs in patients with unresectable/metastatic PDGFRA D842V-mutant GIST. TRIAL REGISTRATION: The NAVIGATOR trial was registered at ClinicalTrials.gov as per July 2015, Identifier: NCT02508532 .

Low Distribution of TIM-3+ Cytotoxic Tumor-Infiltrating Lymphocytes Predicts Poor Outcomes in Gastrointestinal Stromal Tumors.

There are multiple tumor-infiltrating lymphocytes (TILs) and relevant immune checkpoints existing in gastrointestinal stromal tumor (GIST), which provides opportunities and rationales for developing effective immunotherapies. Recent studies have suggested that checkpoint TIM-3/Gal-9 plays a pivotal role on immune response in multiple tumors, similar to the PD-1/PD-L1, emerging as a potential therapeutic target. However, their functions in GIST are unrevealed. Hence, the expression of immune checkpoints TIM-3 and Gal-9, as well as the infiltration of CD8+ T cells and NK cells, is described in 299 cases of GIST specimens. The results showed that TIM-3 and Gal-9 are mainly expressed in TILs, rarely in tumor cells. Expression levels of TIM-3 and Gal-9 significantly differ in varying risks of GIST and exert opposite distribution trends. Indicated by prognosis analysis, high TIM-3 expression of TILs was associated with improved outcome, while low expression levels of TIM-3 in combination with low amounts of CD8+ and CD56+ TILs predict extremely poor survival. The integrated analysis of TIM-3+, CD8+, and CD56+ TILs as one biomarker is a reliable independent predictor of prognosis. In conclusion, low densities of TIM-3+ TILs are associated with poor survival, and integrated immune biomarkers lead to superior predictors of GIST prognosis.

Clinical significance of surgical intervention for imatinib-resistant gastrointestinal stromal tumors in the era of multiple tyrosine kinase inhibitors.

PURPOSE: Imatinib is the standard treatment for unresectable and metastatic GIST. In the late stages, patients undergoing imatinib show drug resistance. Surgical intervention has been occasionally performed for resistant lesions. However, the clinical significance of such intervention remains unclear. METHODS: Between 2006 and 2015, 37 patients were diagnosed with imatinib-resistant GISTs. We performed surgical intervention only for localized resistant lesions. We retrospectively investigated the background characteristics, data on surgical intervention and subsequent treatment, progression-free survival (PFS), and overall survival (OS). RESULTS: Eighteen patients diagnosed with localized resistance received surgical intervention (S-group) and 19 patients diagnosed with generalized resistance were received other TKIs (M-group). In S-group, no serious complications occurred, and all patients restarted imatinib after resection. The median PFS was 14.5 months. Five patients underwent surgical intervention multiple times followed by the continuation of imatinib, and the median duration of imatinib continuation was 22.2 months. Second-line TKIs were administered to 93% of the patients and the dose-intensity and outcome were similar in both groups. The median OS was 47.2 months after surgery. CONCLUSIONS: Surgical intervention could be performed safely and therefore could be followed by the continuation of TKI therapy. Surgical intervention based on the appropriate criteria of resistance might thus be useful for imatinib-resistant GISTs.

Radical resection versus local excision for low rectal gastrointestinal stromal tumor: A multicenter propensity score-matched analysis.

BACKGROUND: The surgical approaches and resection extent for rectal gastrointestinal stromal tumors (GISTs) are controversial due to the low incidence of this disease. A multicenter retrospective cohort study was conducted to compare the postoperative and oncologic outcomes of local excision (LE) and radical resection (RR) in patients with low rectal GIST. PATIENTS AND METHODS: The medical records of rectal GIST patients from 11 large-scale medical centers in China (January 2000-December 2019) were reviewed. All patients were divided into either the LE group or the RR group. Propensity score matching (PSM) was conducted to reduce confounders. RESULTS: A total of 280 patients with low rectal GIST were enrolled. After PSM, 144 patients were included (72 in each group). The LE group showed a higher anal preservation rate (100.0% vs. 76.4%, P < 0.001), shorter operation time (77.1 ± 68.4 min vs. 159.1 ± 83.6 min, P < 0.001), fewer complications (8.3% vs. 22.2%, P = 0.021) and shorter postoperative hospital stay (4.9 ± 4.1 d vs. 10.7 ± 8.1 d, P < 0.001) than the RR group. There was no significant difference in recurrence-free survival (RFS) between the RR and LE groups among patients with tumors ≤2 cm (P = 0.220), and the RR group had a superior RFS than the LE group in patients with tumors >2 cm (P = 0.046). CONCLUSIONS: LE resulted in improved postoperative outcomes and comparable oncological safety with a low rectal GIST of ≤2 cm. However, for patients with a low rectal GIST of >2 cm, RR might be a more appropriate option with better RFS.

[Treatment of soft tissue sarcomas including GIST - Update 2021]. / Therapie der Weichgewebssarkome inklusive GIST ­ Update 2021.

Soft tissue sarcomas are rare tumors that represent a major challenge due to varying clinical presentations and often interdisciplinary treatment concepts. Gold standard for the treatment of localized resectable soft tissue sarcomas is complete surgical removal. So far, multimodality treatment does not represent a clininal standard. However, several newer analyses and studies suggest that a subgroup of patients seems to derive an overall survival benefit from perioperative chemotherapy. In metastatic soft tissue sarcoma systemic therapy is the treatment of choice. Most active drugs are the anthracyclines and ifosfamide. Combination chemotherapy has improved both response rate and progression-free survival at the costs of increased toxicity in comparison to single agent therapy but without impact on overall survival in first-line therapy. In pretreated patients, treatment options consist of trabectedin, pazopanib, gemcitabine plus docetaxel or DTIC, and eribulin. Recent data have shown that histiotype-specific treatment options including targeted therapy represent a major improvement for several sarcoma subtypes.In GIST, imatinib is the gold standard for patients with advanced or metastatic disease. In imatinib refractory or intolerant patients, sunitinib in an individualized treatment schedule is recommended. Regorafenib has been approved for third-line therapy. Recently, avapritinib has been approved for treatment of patients with the so far resistant D842V mutation in the PDGFRA exon 18. Ripretinib has shown very promising activity in forth and further lines of therapy and is already approved in the US. The use of adjuvant imatinib therapy in patients with completely resected localized GIST with a high risk of recurrence has significantly improved overall survival with a treatment duration of 3 years. These results have now been confirmed with a 10 years follow-up analysis.

Avapritinib in unresectable or metastatic PDGFRA D842V-mutant gastrointestinal stromal tumours: Long-term efficacy and safety data from the NAVIGATOR phase I trial.

BACKGROUND: PDGFRA D842V mutations occur in 5-10% of gastrointestinal stromal tumours (GISTs), and previously approved tyrosine kinase inhibitors (TKIs) are inactive against this mutation. Consequently, patients have a poor prognosis. We present an updated analysis of avapritinib efficacy and long-term safety in this patient population. METHODS: NAVIGATOR (NCT02508532), a two-part, open-label, dose-escalation/dose-expansion phase I study, enrolled adult patients with unresectable GISTs. Patients with PDGFRA D842V-mutant GIST were a prespecified subgroup within the overall safety population, which included patients who received ≥1 avapritinib dose. Primary end-points were overall response rate (ORR) and avapritinib safety profile. Secondary end-points were clinical benefit rate (CBR), duration of response (DOR) and progression-free survival (PFS). Overall survival (OS) was an exploratory end-point. RESULTS: Between 7 October 2015 and 9 March 2020, 250 patients enrolled in the safety population; 56 patients were included in the PDGFRA D842V population, 11 were TKI-naïve. At data cut-off, median follow-up was 27.5 months. Safety profile was comparable between the overall safety and PDGFRA D842V populations. In the PDGFRA D842V population, the most frequent adverse events were nausea (38 [68%] patients) and diarrhoea (37 [66%]), and cognitive effects occurred in 32 (57%) patients. The ORR was 91% (51/56 patients). The CBR was 98% (55/56 patients). The median DOR was 27.6 months (95% confidence interval [CI]: 17.6-not reached [NR]); median PFS was 34.0 months (95% CI: 22.9-NR). Median OS was not reached. CONCLUSION: Targeting PDGFRA D842V-mutant GIST with avapritinib resulted in an unprecedented, durable clinical benefit, with a manageable safety profile. Avapritinib should be considered as first-line therapy for these patients.

Clinicopathological characteristics and outcomes of gastrointestinal stromal tumors with high progranulin expression.

BACKGROUND & AIMS: Progranulin (PGRN) is known to promote tumorigenesis and proliferation of several types of cancer cells. However, little is known about the clinicopathological features of patients with gastrointestinal stromal tumors (GISTs) with regard to PGRN expression. METHODS: A retrospective analysis was performed on patients with GISTs who underwent curative surgical resection between 2007 and 2017. PGRN expression was evaluated by immunohistochemical (IHC) analysis and semi-quantitatively categorized (no expression, 0; weak, 1+; moderate, 2+; strong, 3+). Tumors with a staining intensity of 2+ or 3+ were considered high PGRN expression. RESULTS: Fifty-four patients were analyzed; 31 patients (57%) were male. The median age at surgery was 60 years (range, 33-79), and the most common primary site was the stomach (67%). Thirty-five patients (65%) had spindle histology; 42 patients (78%) were separated as a high-risk group according to the modified National Institutes of Health (NIH) classification. High PGRN-expressing tumors were observed in 27 patients (50%), had more epithelioid/mixed histology (68% vs. 32%; p = 0.046), and KIT exon 11 mutations (76% vs. 24%; p = 0.037). Patients with high PGRN-expressing tumors had a worse recurrence-free survival (RFS) (36% of 5-year RFS) compared to those with low PGRN-expressing tumors (96%; p<0.001). Multivariate analysis showed that high PGRN expression and old age (>60 years) were independent prognostic factors for poor RFS. CONCLUSIONS: High PGRN-expressing GISTs showed more epithelioid/mixed histology and KIT exon 11 mutations. PGRN overexpression was significantly associated with poor RFS in patients with GISTs who underwent curative resection.

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

BACKGROUND: Gastrointestinal stromal tumours (GISTs) located in the jejunum or ileum (JI-GIST) are considered worse prognosis compared to those of gastric (G-GIST) location. It has been suggested that this dogma should be revised. The aim of this study was to describe the characteristics of jejunoileal GISTs and its prognosis and to compare them with G-GISTs in the era of imatinib. METHODS: We retrospectively reviewed the clinical histories of all the patients diagnosed with GISTs between January 2000 and November 2016: Clinical and pathological data, as recurrence, metastatic state, disease-free survival (DFS) as well as overall survival (OS) rates of patients were reviewed. RESULTS: JI-GIST patients comprise 29 cases (37.7%). Compared to G-GIST, JI-GIST patients had undergone emergency surgery more frequently (37.9% vs. 10.4%, p = 0.007). According to the NIH-Fletcher classification, the low or very-low risk group represents 17.2% of JI-GISTs as opposed to 37.6% of G-GISTs (p < 0.005). When the AFIP-Miettinen system was used the low or very-low group represented 17.2% of JI-GISTs vs. 58.4% in the G-GISTs group (p < 0.001). Both local recurrence (24.1% vs. 12.5%, p < 0.05) and metastatic rate (34.5% vs. 22.9%, p < 0.05) were higher in the JI-GIST group than in G-GIST. 5- and 10-year DFS and 10-year OS rate were lower for JI-GIST (54.5% and 39.6% vs. 77.2% and 60.8%, and 57.9% vs. 65%, respectively, p < 0.05). CONCLUSIONS: The observed differences between both groups in DFS and OS rates at long term could be attributed to the effect of imatinib.