Discontinuation versus continuation of imatinib in patients with advanced gastrointestinal stromal tumours (BFR14): exploratory long-term follow-up of an open-label, multicentre, randomised, phase 3 trial.

BACKGROUND: The long-term impact of tyrosine kinase inhibitor (TKI) discontinuation on resistance and survival in patients with advanced gastrointestinal stromal tumours (GIST) is unclear. We report the exploratory long-term outcomes of patients with advanced GIST stopping imatinib in the BFR14 trial. METHODS: BFR14, an open-label, randomised, phase 3 trial, was done in 17 comprehensive cancer centres or hospitals across France. Patients with advanced GIST aged 18 years or older with an Eastern Cooperative Oncology Group performance status of 0-3, no previous treatment with imatinib, and no previous malignancy were eligible. Patients were treated with oral imatinib 400 mg daily. Patients with a complete or partial response, or stable disease, according to Response Evaluation Criteria in Solid Tumours (1.0) at 1 year, 3 years, and 5 years from the start of treatment were randomly assigned (1:1) to treatment discontinuation until progression (interruption group) or treatment continuation until progression (continuation group). Randomisation was done centrally with computer-generated permuted blocks of two and six patients stratified by participating centre and presence or absence of residual disease on CT scan. The primary endpoint was progression-free survival. Secondary endpoints included time to imatinib resistance and overall survival. Analyses were conducted on an intention-to-treat basis in all randomly assigned patients who were not lost to follow-up. This trial is registered with ClinicalTrial.gov, NCT00367861. FINDINGS: Between May 12, 2003, and March 16, 2004, after 1 year of imatinib, 32 patients were randomly assigned to the interruption group and 26 to the continuation group. Between June 13, 2005, and May 30, 2007, after 3 years of imatinib, 25 patients were randomly assigned to the interruption group and 25 to the continuation group. Between Nov 9, 2007, and July 12, 2010, after 5 years of imatinib, 14 patients were randomly assigned to the interruption group and 13 to the continuation group. Median follow-up was 235·2 months (IQR 128·8-236·6) after the 1-year randomisation, 200·9 months (190·2-208·4) after the 3-year randomisation, and 164·5 months (134·4-176·4) after the 5-year randomisation. Median progression-free survival in the interruption group versus the continuation group after 1 year of imatinib was 6·1 months (95% CI 2·5-10·1) versus 27·8 months (19·5-37·9; hazard ratio [HR] 0·36 [95% CI 0·20-0·64], log-rank p=0·0003), after 3 years of imatinib was 7·0 months (3·5-11·7) versus 67·0 months (48·8-85·6; 0·15 [0·07-0·32], log-rank p<0·0001), and after 5 years of imatinib was 12·0 months (9·0-16·6) versus not reached (NR; NR-NR; 0·13 [0·03-0·58], log-rank p=0·0016). The median time to imatinib resistance after 1 year of imatinib was 28·7 months (95% CI 18·1-39·1) versus 90·6 months (25·3-156·1; HR 0·93 [95% CI 0·51-1·71], log-rank p=0·82), after 3 years was 66·2 months (43·0-89·6) versus 127·3 months (15·0-239·7; 0·35 [0·17-0·72, log-rank p=0·0028), and after 5 years was 58·6 months (0·0-167·4) versus NR (NR-NR; 0·24 [0·05-1·12], log-rank p=0·049). Median overall survival after 1 year of imatinib was 56·0 months (95% CI 30·3-82·9) versus 105·0 months (20·6-189·6; HR 0·84 [95% CI 0·46-1·54], log-rank p=0·57), after 3 years was 104·0 months (90·7-118·7) versus 134·0 months (89·7-178·3; 0·40 [0·20-0·82], log-rank p=0·0096), and after 5 years was NR (NR-NR) versus 110·4 months (82·7-154·1; 1·28 [0·41-3·99]; log-rank p=0·67), INTERPRETATION: Imatinib interruption in patients with GIST without progressive disease is not recommended. Imatinib interruption in non-progressing patients with GIST was associated with rapid progression, faster resistance to imatinib, and shorter overall survival in the long-term follow-up when compared with imatinib continuation in patients after 3 years and 5 years of imatinib. FUNDING: Centre Léon Bérard, INCa, CONTICANET, Ligue Contre le Cancer, and Novartis.

Prospective evaluation of quantitative response parameter in patients with Gastrointestinal Stroma Tumor undergoing tyrosine kinase inhibitor therapy-Impact on clinical outcome.

The purpose of this study was to determine if dual-energy CT (DECT) vital iodine tumor burden (ViTB), a direct assessment of tumor vascularity, allows reliable response assessment in patients with GIST compared to established CT criteria such as RECIST1.1 and modified Choi (mChoi). From 03/2014 to 12/2019, 138 patients (64 years [32-94 years]) with biopsy proven GIST were entered in this prospective, multi-center trial. All patients were treated with tyrosine kinase inhibitors (TKI) and underwent pre-treatment and follow-up DECT examinations for a minimum of 24 months. Response assessment was performed according to RECIST1.1, mChoi, vascular tumor burden (VTB) and DECT ViTB. A change in therapy management could be because of imaging (RECIST1.1 or mChoi) and/or clinical progression. The DECT ViTB criteria had the highest discrimination ability for progression-free survival (PFS) of all criteria in both first line and second line and thereafter treatment, and was significantly superior to RECIST1.1 and mChoi (p < .034). Both, the mChoi and DECT ViTB criteria demonstrated a significantly early median time-to-progression (both delta 2.5 months; both p < .036). Multivariable analysis revealed 6 variables associated with shorter overall survival: secondary mutation (HR = 4.62), polymetastatic disease (HR = 3.02), metastatic second line and thereafter treatment (HR = 2.33), shorter PFS determined by the DECT ViTB criteria (HR = 1.72), multiple organ metastases (HR = 1.51) and lower age (HR = 1.04). DECT ViTB is a reliable response criteria and provides additional value for assessing TKI treatment in GIST patients. A significant superior response discrimination ability for median PFS was observed, including non-responders at first follow-up and patients developing resistance while on therapy.

Safety and efficacy of percutaneous image-guided ablation for soft tissue sarcoma metastases to the liver.

PURPOSE: To evaluate outcomes following percutaneous image-guided ablation of soft tissue sarcoma metastases to the liver. MATERIALS AND METHODS: A single-institution retrospective analysis of patients with a diagnosis of metastatic soft tissue sarcoma who underwent percutaneous image-guided ablation of hepatic metastases between January 2011 and December 2021 was performed. Patients with less than 60 days of follow-up after ablation were excluded. The primary outcome was local tumor progression-free survival (LPFS). Secondary outcomes included overall survival, liver-specific progression-free survival. and chemotherapy-free survival. RESULTS: Fifty-five patients who underwent percutaneous ablation for 84 metastatic liver lesions were included. The most common histopathological subtypes were leiomyosarcoma (23/55), followed by gastrointestinal stromal tumor (22/55). The median treated liver lesions was 2 (range, 1-8), whereas the median size of metastases were 1.8 cm (0.3-8.7 cm). Complete response at 2 months was achieved in 90.5% of the treated lesions. LPFS was 83% at 1 year and 80% at 2 years. Liver-specific progression-free survival was 66% at 1 year and 40% at 2 years. The overall survival at 1 and 2 years was 98% and 94%. The chemotherapy-free holiday from the start of ablation was 71.2% at 12 months. The complication rate was 3.6% (2/55); one of the complications was Common Terminology Criteria for Adverse Events grade 3 or higher. LPFS subgroup analysis for leiomyosarcoma versus gastrointestinal stromal tumor suggests histology-agnostic outcomes (2 years, 89% vs 82%, p = .35). CONCLUSION: Percutaneous image-guided liver ablation of soft tissue sarcoma metastases is safe and efficacious.

Survival of patients with ruptured gastrointestinal stromal tumour treated with adjuvant imatinib in a randomised trial.

BACKGROUND: Patients with ruptured gastrointestinal stromal tumour (GIST) have poor prognosis. Little information is available about how adjuvant imatinib influences survival. METHODS: We explored recurrence-free survival (RFS) and overall survival (OS) of patients with ruptured GIST who participated in a randomised trial (SSG XVIII/AIO), where 400 patients with high-risk GIST were allocated to adjuvant imatinib for either 1 year or 3 years after surgery. Of the 358 patients with confirmed localised GIST, 73 (20%) had rupture reported. The ruptures were classified retrospectively using the Oslo criteria. RESULTS: Most ruptures were major, four reported ruptures were reclassified unruptured. The 69 patients with rupture had inferior RFS and OS compared with 289 patients with unruptured GIST (10-year RFS 21% vs. 55%, OS 59% vs. 78%, respectively). Three-year adjuvant imatinib did not significantly improve RFS or OS of the patients with rupture compared with 1-year treatment, but in the largest mutational subset with KIT exon 11 deletion/indel mutation OS was higher in the 3-year group than in the 1-year group (10-year OS 94% vs. 54%). CONCLUSIONS: About one-fifth of ruptured GISTs treated with adjuvant imatinib did not recur during the first decade of follow-up. Relatively high OS rates were achieved despite rupture. CLINICAL TRIAL REGISTRATION: NCT00116935.

Survival of advanced/recurrent gastrointestinal stromal tumors treated with tyrosine kinase inhibitors in Taiwan: a nationwide registry study.

BACKGROUND: Most gastrointestinal stromal tumors (GISTs) harbor c-KIT or PDGFRA mutations. Administration of tyrosine kinase inhibitors (TKIs) has significantly improved the survival of patients with GISTs. We aimed to evaluate the clinical outcome of advanced or recurrent GIST patients in Taiwan. METHODS: Patients diagnosed between 2010 and 2020 were enrolled. The collected data included baseline characteristics, treatment pattern, treatment outcome, genetic aberrations and survival status. Progression-free survival (PFS) and overall survival (OS) were analyzed and plotted with the Kaplan-Meier method. Cox regression analysis was used to analyze the prognostic factors of survival. RESULTS: A total of 224 patients with advanced or recurrent GISTs treated with TKIs were enrolled. All patients received imatinib treatment. Ninety-three and 42 patients received sunitinib and regorafenib treatment, respectively. The 48-month PFS and OS rates for patients treated with imatinib were 50.5% and 79.5%, respectively. c-KIT exon 9 and PDGFRA mutations were prognostic factors for a poor PFS and PDGFRA mutation was a prognostic factor for a poor OS in patients treated with imatinib in multivariate Cox regression analysis. The median PFS of patients who received sunitinib treatment was 12.76 months (95% confidence interval (CI), 11.01-14.52). Patients with c-KIT exon 9 mutations had a longer PFS than those with other genetic aberrations. The median PFS of patients treated with regorafenib was 7.14 months (95% CI, 3.39-10.89). CONCLUSIONS: We present real-world clinical outcomes for advanced GIST patients treated with TKIs and identify mutational status as an independent prognostic factor for patient survival.

Impact of systemic steroids on the efficacy of first line imatinib treatment of patients with advanced gastrointestinal stromal tumors (GISTs).

BACKGROUND: Effective management of adverse events is required to maintain sufficient imatinib dosing when treating patients with gastrointestinal stromal tumors (GISTs). Skin rash is a common adverse event of imatinib, which can be effectively controlled by systemic steroid treatment without imatinib dose modification or interruption. However, the impact of the use of systemic steroids on the efficacy of imatinib treatment remains unclear. METHODS: Between October 2014 and February 2022, 277 consecutive patients from a prospective registry of GIST patients were included as the study population. Patients who started systemic steroids due to grade ≥ 3 skin rash or grade 2 skin rash with grade 2 pruritis were classified as the steroid group, whereas patients who did not develop a skin rash or those who did not require steroids for a mild skin rash were classified as the control group. Efficacy outcomes were compared between the two groups. RESULTS: Among the 277 patients, 30 (10.8%) were treated with systemic steroids for skin rash. There was no significant difference in progression free survival (PFS) or overall survival (OS) between the steroid and control groups (3-year PFS, 67.7% vs. 65.1%, p = 0.53; 3-year OS, 91% vs. 89.9%, p = 0.67, respectively). The use of systemic steroids was not an independent factor associated with PFS (hazard ratio 0.73, 95% confidence interval 0.36-1.49, p = 0.39) and OS (hazard ratio 0.37, 95% confidence interval 0.12-1.18, p = 0.09). In the steroid group, patients who successfully maintained the imatinib dosage showed a trend toward more favorable survival outcomes than those who did not (3-year PFS, 73.3% vs. 44.4%, p = 0.34; 3-year OS, 95.8% vs. 75.0%, p = 0.15, respectively). CONCLUSIONS: The use of systemic steroids for the control of imatinib induced severe skin rash did not adversely affect the efficacy outcomes of imatinib in patients with advanced GIST.

Adjuvant imatinib in high-risk resected gastrointestinal stromal tumors: Merely delaying the inevitable?

INTRODUCTION: Patients with high-risk resected gastrointestinal stromal tumors (GIST) receiving adjuvant imatinib have improved recurrence-free survival (RFS), however whether a complete cytocidal effect exists is unknown. We investigated this using a normalized recurrence timeline measured from end of oncologic treatment (EOOT), defined as the later of resection or end of adjuvant therapy. METHODS: We reviewed patients with resected high-risk GIST at our cancer center from 2003 to 2018. RFS (measured from resection and EOOT), overall survival (OS), and time to imatinib resistance (TTIR) were analyzed using Kaplan-Meier analysis and multivariable Cox proportional hazards modeling. The performance of the Memorial Sloan Kettering (MSK) GIST nomogram was assessed. RESULTS: We identified 86 patients with high-risk GIST with a median 106 months of postsurgical follow-up. One-third (n = 29; 34%) did not receive adjuvant imatinib, while 57 (66%) did for a median of 3 years. The MSK nomogram-predicted 5-year RFS for patients receiving adjuvant imatinib was similar to those who did not (29% vs. 31%, p = 0.64). When RFS was measured from EOOT, the MSK-predicted RFS was independently associated with EOOT RFS (hazard ratio 0.22, p = 0.02), while adjuvant imatinib receipt and duration were not. Neither receipt nor duration of adjuvant imatinib were associated with TTIR or OS (all p > 0.05). CONCLUSIONS: Treatment with adjuvant imatinib delays, but does not clearly impact ultimate recurrence, TTIR, or OS, suggesting many patients with high-risk GIST may receive adjuvant imatinib unnecessarily. Additional studies are needed to establish the benefit of adjuvant therapy versus initiating therapy at first radiographic recurrence.

Discontinuation of imatinib in patients with oligometastatic gastrointestinal stromal tumour who are in complete radiological remission: a prospective multicentre phase II study.

INTRODUCTION: Metastatic gastrointestinal stromal tumour (GIST) is considered incurable, and life-long treatment with tyrosine kinase inhibitors is recommended. We investigated whether selected patients with metastatic GIST may remain in durable remission despite imatinib discontinuation. PATIENTS: In this 1-group, prospective, multicentre phase II trial selected patients with oligometastatic (≤3 metastases) GIST discontinued imatinib treatment. Eligible patients had been treated with imatinib >5 years without progression and had no radiologically detectable metastases after metastasectomy, radiofrequency ablation (RFA) or complete response to imatinib. The primary endpoint was progression-free survival (PFS) 3-years after stopping imatinib. Overall survival (OS) and quality of life (QoL) were secondary endpoints. RESULTS: The trial closed prematurely due to slow accrual. Between January 5, 2017, and June 5, 2019, 13 patients were enrolled, of whom 12 discontinued imatinib. The median follow-up time was 55 months (range, 36 to 69) after study entry. Five (42%) of the 12 eligible patients remained progression free, and seven (58%) progressed with a median time to progression 10 months. Median PFS was 23 months and the estimated 3-year PFS 41%. Six of the seven patients who progressed restarted imatinib, and all six responded. Three-year OS was 100%, and all patients were alive at the time of the study analysis. QoL measured 5 and 11 months after discontinuation of imatinib demonstrated improvement compared to the baseline. INTERPRETATION: A substantial proportion of selected patients with oligometastatic GIST treated with imatinib and metastasis surgery/RFA may remain disease-free for ≥3 years with improved QoL after stopping of imatinib.

The influence of lymphadenectomy on the prognosis of small intestinal stromal tumors: a study based on the SEER database.

BACKGROUND: Small intestinal stromal tumors (SISTs) typically require surgical treatment. However, the impact of lymphadenectomy (LA) on long-term prognosis in patients remains unclear. Therefore, we plan to analyze the effect of LA on the prognosis of patients with SISTs using the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: Data on SISTs patients between 2000 and 2019 were obtained from the SEER database. Multiple imputation (MI) was employed to handle missing data, while propensity score matching (PSM) was conducted to mitigate selection bias in the comparative assessments between the LA group and the No-LA group. Kaplan-Meier analyses and multivariate Cox proportional hazards models were utilized to evaluate both overall survival (OS) and cancer-specific survival (CSS). RESULTS: A total of 2412 patients diagnosed with SISTs were included in the study, with 879 undergoing LA and 1533 not undergoing LA. There were no significant differences observed between the two cohorts concerning long-term OS (hazard ratio [HR] 0.97, 95% confidence interval [CI] 0.84-1.13, P = 0.720) and CSS (HR 1.05, 95% CI 0.86-1.29, P = 0.622). After PSM, 1596 patients (798 in the LA group and 789 in the No-LA group) were matched for comparison. There was also no difference in long-term OS and CSS between the two groups. Subgroup analysis revealed that in the age group > 60 years, the CSS in the No-LA group was superior to that in the LA group. Multivariate Cox regression analysis revealed that age, M stage, marital status, and mitotic rate are significant risk factors influencing OS and CSS. CONCLUSIONS: Conducting LA in patients with SISTs does not enhance long-term prognosis. For patients aged over 60 years, it may be more advisable to refrain from performing LA.

The impact of gender on survival outcomes in patients with small intestinal stromal tumors: a comprehensive analysis using the SEER database.

BACKGROUND: Small intestinal stromal tumors (SISTs) are a rare type of mesenchymal tumor. Gender is known to influence the incidence and prognosis of various tumors, but its role on the survival of SISTs at the population level remains unclear. Therefore, we aim to explore the relationship between gender and the prognosis of SISTs using the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: Data on SISTs patients from 2000 to 2019 were derived from the SEER database. Multiple imputation was used to address missing data. Kaplan-Meier analyses and Cox proportional hazard models were applied to evaluate the impact of demographic and clinical characteristics on overall survival (OS) and cancer-specific survival (CSS). RESULTS: A total of 3513 patients with SISTs were analyzed, including 1921 males and 1592 females. Kaplan-Meier analysis coupled with log-rank testing demonstrated a significantly higher mortality rate among male patients compared to females (P < 0.001). Notably, female patients exhibited superior OS (hazard ratio [HR] 0.808, 95% confidence interval [CI] 0.724-0.902, P < 0.001) and CSS (HR 0.801, 95% CI 0.692-0.927, P = 0.003) compared to male patients. While the mean 1-year CSS rates were comparable between genders (95.3% for males vs. 96.0% for females, P = 0.332), male patients consistently showed lower mean survival rates at 3-, 5-, and 10-year intervals. Surgical intervention significantly boosted 5-year OS and CSS rates in both male and female patients (P < 0.001). Multivariate Cox regression analysis identified age, sex, grade, TNM stage, surgery, and mitotic rate as independent risk factors for OS and CSS in patients with SISTs. CONCLUSIONS: Our findings suggest that male patients with SISTs have a higher risk of mortality compared to female patients, indicating that gender may serve as a predictive indicator for survival in this patient population.

Clinical outcomes of endoscopic resection for the treatment of intermediate- or high-risk gastric small gastrointestinal stromal tumors: a multicenter retrospective study.

BACKGROUND AND AIMS: Many studies of gastric gastrointestinal stromal tumors (g-GISTs) following endoscopic resection (ER) have typically focused on tumor size, with most tumors at low risk of aggressiveness after risk stratification. There have been few systematic studies on the oncologic outcomes of intermediate- or high-risk g-GISTs after ER. METHODS: From January 2014 to January 2020, we retrospectively collected patients considered at intermediate- or high-risk of g-GISTs according to the modified NIH consensus classification system. The primary outcome was overall survival (OS). RESULTS: Six hundred and seventy nine (679) consecutive patients were diagnosed with g-GISTs and treated by ER between January 2014 and January 2020 in three hospitals in Shanghai, China. 43 patients (20 males and 23 females) were confirmed at intermediate-or high-risk. The mean size of tumors was 2.23 ± 1.01 cm. The median follow-up period was 62.02 ± 15.34 months, with a range of 28 to 105 months. There were no recurrences or metastases, even among patients having R1 resections. The 5-year OS rate was 97.4% (42/43). CONCLUSION: ER for intermediate- or high-risk gastric small GISTs is a feasible and safe method, which allows for a wait-and-see approach before determining the necessity for imatinib adjuvant or surgical treatment. This approach to g-GISTs does require that patients undergo close follow-up.

Comparing gastrointestinal stromal tumor outcomes between geriatric and non-geriatric patients: A population-based analysis.

BACKGROUND: Gastrointestinal Stromal Tumors (GISTs) are the most common mesenchymal tumors of the GI tract. SEER is an extensive cancer database which proves useful in analyzing population trends. This analysis investigated GIST outcomes between geriatric & non-geriatric patients. METHODS: SEER*STAT 8.4.0.1 was used to extract relevant GIST data from 2000 to 2019. Geriatric age was defined as ≥70 years. Variables included age, sex, surgery, cancer-specific death, and overall survival. Statistical tests included univariate analysis using KM survival estimate (95% confidence interval) to calculate 5-year survival (5YS). Log-Rank tests determined statistical significance. Multivariable Cox's PH regression estimated the geriatric hazard death ratio adjusted for sex, stage, and surgery. RESULTS: The number of patients included was 13,579, yielding overall 5YS of 68.6% (95% CI 67.7-69.5). Cancer-specific death was 39.11% in 2000 & 3.33% in 2019. Non-geriatric & geriatric patient data yielded 5YS of 77.4% (76.4%-78.3%) and 53.3% (51.7%-54.8%) respectively (p < 0.0001). For no surgery/surgery, younger patient data yielded 5YS of 48.7% (45.8%-51.4%) and 83.7% (82.7%-84.7%) respectively (p < 0.0001); geriatric data yielded 5YS of 29.3% (26.5%-32.1%) and 62.8% (60.8%-64.6%) respectively (p < 0.0001). Multivariable analysis yielded a geriatric hazard death of 2.56 (2.42-2.70) (p < 0.0001). CONCLUSIONS: Cancer-specific death decreased since 2000, indicating an improvement in survival & treatment methods. Observed lower survival rates overall in the geriatric group. Surgery appeared to enhance survival rates in both groups, suggesting that surgery is an important factor in GIST survival regardless of age. Large prospective studies will help define clinical management for geriatric patients.

A systematic review and meta-analysis of neoadjuvant imatinib use in locally advanced and metastatic gastrointestinal stromal tumors.

BACKGROUND: Several doubts remain regarding the optimal use of neoadjuvant imatinib in gastrointestinal stromal tumors (GISTs), such as ideal treatment duration, patient selection, and long-term survival outcomes. This manuscript provides a comprehensive review on neoadjuvant imatinib treatment outcomes and facilitate evidence-based decision-making for the use of imatinib therapy in GISTs. METHODS: Four databases (PubMed, EMBASE, Scopus, and Cochrane Library) were searched from inception to September 9, 2023. Meta-analyses of proportions were performed for the outcomes of R0 resection, disease responses, and 1-year, 3-year, and 5-year overall survival (OS) as well as 1-year, 3-year, and 5-year disease free survival (DFS). Sensitivity analyses in the form of leave-one-out analyses, meta-regression, and subgroup analyses were performed for outcomes with substantial statistical heterogeneity. RESULTS: The search yielded 1254 articles, and 36 studies were included in our analysis. Meta-analysis of proportions revealed that 1-year, 3-year, and 5-year OS was 100%, 94%, and 88%, while 1-year, 3-year and 5-year DFS was 99%, 89%, and 79%, respectively. An R0 resection rate of 89% and a disease response rate of 67% was achieved after a mean duration of treatment of 8.41 ± 0.367 months. KIT exon 9 mutation was significantly associated with poorer 5-year DFS. CONCLUSION: This study quantified key outcomes for neoadjuvant imatinib in locally advanced and metastatic or recurrent GIST. Patients with gastric and rectal tumous stand to benefit from neoadjuvant imatinib with an optimal treatment duration of 8 months. Furthermore, the potential utility of mutational analysis in guiding treatment with neoadjuvant imatinib was demonstrated.

Is laparoscopic approach as treatment of large gastric GIST acceptable?

AIM: Laparoscopic surgery is widely used for small gastric gastrointestinal stromal tumors (GISTs) (≤ 5 cm) but remains a controversial approach for larger gastric GISTs (> 5 cm). This study aims to compare short- and long-term outcomes of laparoscopic resection in comparison with open resection for gastric GISTs measuring over 5 cm. METHOD: All patients receiving surgery for gastric GIST > 5 cm between 2000 and 2021 in a single tertiary hospital were included. Data were collected from prospectively maintained records. Kaplan-Meier method and log rank test were used to compare survival outcomes. RESULTS: Among 108 included patients, 59 patients had minimally invasive (MI) surgery (54.6%) whereas 49 patients had open surgery (46.4%). The rate of overall postoperative morbidity was 14.8% and the median length was significantly shorter in the MI group [4 (range 2-30) vs. 7 (range 4-33) days; P = 0.007]. The overall R0 resection rate was 98.2% and the rate of tumor rupture was 13%, not different between the two groups. Recurrence occurred in 24% of the whole population without any difference between groups (20.3% vs. 28.7%, p = 0.31). Minimally invasive surgery was not found as a negative prognostic disease-free survival factor. CONCLUSION: Laparoscopic surgery could be a safe and feasible alternative to open surgery in large gastric GIST, bringing the benefits of minimally invasive surgery without compromising oncologic results.

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.

Single-cell transcriptome analysis revealed the heterogeneity and microenvironment of gastrointestinal stromal tumors.

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the human gastrointestinal tract. In this study, we performed single-cell RNA sequencing (RNA-seq) on intra- and peri-tumor tissues from GIST patients with the aim of discovering the heterogeneity of tumor cells in GIST and their interactions with other cells. We found four predominating cell types in GIST tumor tissue, including T cells, macrophages, tumor cells, and NK cells. Tumor cells could be clustered into two groups: one was highly proliferating and associated with high risk of metastasis, the other seemed "resting" and associated with low risk. Their clinical relevance and prognostic values were confirmed by RNA-seq of 65 GIST samples. T cells were the largest cell type in our single-cell data. Two groups of CD8+ effector memory (EM) cells were in the highest clonal expansion and performed the highest cytotoxicity but were also the most exhausted among all T cells. A group of macrophages were found polarized to possess both M1 and M2 signatures, and increased along with tumor progression. Cell-to-cell interaction analysis revealed that adipose endothelial cells had high interactions with tumor cells to facilitate their progression. Macrophages were at the center of the tumor microenvironment, recruiting immune cells to the tumor site and having most interactions with both tumor and nontumor cells. In conclusion, we obtained an overview of the GIST microenvironment and revealed the heterogeneity of each cell type and their relevance to risk classifications, which provided a novel theoretical basis for learning and curing GISTs.

Outcome of 1000 Patients With Gastrointestinal Stromal Tumor (GIST) Treated by Surgery in the Pre- and Post-imatinib Eras.

OBJECTIVE: To characterize the results of surgery for gastrointestinal stromal tumor (GIST) in the pre and post-imatinib eras at a single institution and to identify current prognostic clinicopathologic factors. BACKGROUND: Imatinib has radically changed the management of GIST, yet the magnitude of impact on outcome across the spectrum of GIST presentation and relevance of historical prognostic factors are not well defined. METHODS: We retrospectively analyzed 1000 patients who underwent surgery for GIST at our institution from 1982 to 2016. Patients were stratified by presentation status as primary tumor only (PRIM), primary with synchronous metastasis (PRIM + MET), or metachronous recurrence/metastases (MET), and also imatinib era (before and after it became available). Cox proportional-hazard models and Kaplan-Meier methods were used to model and estimate overall survival (OS) and recurrence-free survival (RFS). RESULTS: OS was longer in the imatinib era compared with the pre-imatinib era in each presentation group, including in Miettinen high-risk primary tumors. Among PRIM patients from the pre-imatinib era, tumor site, size, and mitotic rate were independently associated with OS and RFS on multivariate analysis. PRIM patients in the imatinib era who received imatinib (neoadjuvant and/or adjuvant) had higher risk tumors, but after adjusting for treatment, only size >10 cm remained independently prognostic of RFS [hazard ratio (HR) 3.85, 95% confidence interval (CI) 2.00-7.40, P < 0.0001) and OS (HR 3.37, 95% CI 1.60-7.13, P = 0.001)]. CONCLUSIONS: Patients treated in the imatinib era had prolonged OS across all presentations. In the imatinib era, among site, size, and mitotic rate, high-risk features were associated with treatment with the drug, but only size >10 cm correlated with outcome. Imatinib should still be prescribed for patients with high-risk features.

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.

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 .

Imatinib-induced pancreatic hypertrophy in patients with gastrointestinal stromal tumor: Association with overall survival.

OBJECTIVES: To investigate the frequency of imatinib-induced pancreatic complications and determine whether these are survival prognostic factors in patients with gastrointestinal stromal tumor (GIST). METHODS: This retrospective multicenter study included patients with histopathologically diagnosed GIST treated with imatinib who underwent computed tomography (CT) within 100 days before (pretreatment CT) and 500 days after (post-treatment CT) imatinib initiation (January 2004-December 2019). Forty-eight patients (63.0 ± 12.1 years, 30 men) were included. Two blinded radiologists independently measured pancreatic volumes. Pancreatic volume on pretreatment CT was compared with that of the control (within 1 year prior to pretreatment CT) and the first two post-treatment CTs using paired t-tests. Thresholds for pancreatic hypertrophy and atrophy were defined using a log-rank test. The prognostic importance of pancreatic hypertrophy was further analyzed using multivariate Cox proportional hazard regression models. RESULTS: Pancreatic volume was significantly higher for the first post-treatment CT than pretreatment CT (71.5 cm3 vs. 67.4 cm3, P = .027), whereas no significant difference was observed between the pretreatment and control CTs. Optimal thresholds for pancreatic hypertrophy and atrophy were defined as an 22% increase and 30% decrease and found in 20 and three patients, respectively. Pancreatic hypertrophy was significantly associated with reduced survival [hazard ratio = 2.9 (95% confidence interval, 1.3-6.5), P = .0088]. No patients showed serum lipase elevation, nor were they suspected of having acute pancreatitis. CONCLUSION: There was frequent asymptomatic pancreatic swelling in patients with GIST after imatinib treatment, and a ≥22% increase in pancreatic volume was a predictor of reduced survival.