Adjuvant treatment of GIST with imatinib: Solid ground or still quicksand? A comment on behalf of the EORTC Soft Tissue and Bone Sarcoma Group, the Italian Sarcoma Group, the NCRI Sarcoma Clinical Studies Group (UK), the Japanese Study Group on GIST, the French Sarcoma Group and the Spanish Sarcoma Group (GEIS)

Next questions on gastrointestinal stromal tumors: unresolved challenges and future directions

PURPOSE OF REVIEW

Despite remarkable progress in the management of gastrointestinal stromal tumors (GISTs), critical challenges persist. Key aspects such as risk stratification, the optimal duration of adjuvant therapy, and strategies to enhance the efficacy of first-line treatment remain subjects of ongoing debate. This review explores emerging concepts and innovative approaches aimed at refining patient selection and optimizing therapeutic decision-making to further improve clinical outcomes.

RECENT FINDINGS

Molecular and genomic parameters have the potential to enhance traditional risk models, enabling more precise stratification of high-risk patients. Innovations in artificial intelligence and liquid biopsy are emerging as powerful tools for refining predictions of recurrence and treatment response. Meanwhile, the definition and prognostic significance of tumor rupture remain pivotal challenges that influence both risk assessment and adjuvant therapy decisions. Furthermore, transcriptomic and multiomic analyses have unveiled distinct GIST subtypes with significant prognostic and therapeutic implications, paving the way for more tailored treatment strategies.

SUMMARY

Integrating molecular features into clinical decision making may refine risk assessment and personalize the treatment in patients with GIST. Future research should focus on validating these tools and redefine clinical trial designs to accelerate drug development for this rare disease.

Identification and validation of protein biomarkers for predicting gastrointestinal stromal tumor recurrence

We conducted a proteomic analysis using mass spectrometry to identify and validate protein biomarkers for accurately predicting recurrence risk in gastrointestinal stromal tumors (GIST) patients, focusing on differentially expressed proteins in metastatic versus primary GIST tissues. We selected five biomarkers-GPX4, RBM4, TPM3, PFKFB2, and PGAM5-and validated their expressions in primary tumors of recurrent and non-recurrent GIST patients via immunohistochemistry. Our analysis of the association between these biomarkers with recurrence-free survival (RFS) and overall survival (OS), along with their interrelationships, revealed that immunohistochemistry confirmed significantly higher expressions of these biomarkers in primary GIST tissues of recurrent patients. Kaplan-Meier survival analysis showed that high expressions of GPX4, RBM4, TPM3, PFKFB2, and PGAM5 correlated with lower RFS, and GPX4 and RBM4 with lower OS. All biomarker pairs showed positive associations, with high expressions correlating with increased recurrence rates, and GPX4 and RBM4 with higher mortality rates. In conclusion, the biomarkers GPX4, RBM4, TPM3, PFKFB2, and PGAM5 are clinically relevant for predicting GIST recurrence, with their high expressions in primary tumors linked to poorer RFS and OS. They serve as potential prognostic indicators, enabling early treatment and improved outcomes. The observed interrelationships among these biomarkers further validate their accuracy in predicting GIST recurrence.

Changes in imatinib plasma trough level during long-term treatment in patients with intermediate- or high-risk gastrointestinal stromal tumors: Relationship between covariates and imatinib plasma trough level

Background

Imatinib is the first-line adjuvant treatment for gastrointestinal stromal tumors (GISTs). Considering that some studies have suggested that imatinib (IM) plasma trough levels (C_min) change with time, the aim of this study is to assess the changes in IM C_min in patients with GIST in a long-term study and to elucidate the relationships between clinicopathological features and IM C_min.

Methods

In 204 patients with intermediate- or high-risk GIST who were taking IM, IM C_min was analyzed. Patient data were grouped according to the duration of medication (A: 1-3 months, B: 4-6 months, C: 7-9 months, D: 10-12 months, E: ≤12 months, F: 12<-≤36 months, G: >36 months). The correlation between IM C_min at different time stages and clinicopathological characteristics was assessed.

Results

Statistically significant differences were observed between Groups A, C, and D (P = 0.049 and 0.01, respectively). In Group E, IM C_min correlated with sex (P = 0.049) and age (P = 0.029) and negatively correlated with body weight, height, and body surface area (P = 0.007, 0.002, and 0.001, respectively). In Groups F and G, IM C_min was significantly higher in non-gastric operation patients than in patients with gastrectomy (P = 0.002, 0.036) and was significantly higher in patients with the primary sites of others than in the stomach (P < 0.001, = 0.012). In addition, IM C_min was much higher in patients with mutation sites other than KIT exon 11 in Group F (P = 0.011).

Conclusion

This is the first study of IM C_min during the long-term treatment of patients with intermediate- or high-risk GIST. IM C_min was the highest for the first 3 months and then declined, and long-term administration of IM showed a relatively stable plasma trough level. The IM C_min correlated with different clinical characteristics at different durations of medication. This meant that future "trough level-clinicopathological characteristics" analyses should be time-point-specific. We also need to formulate time-specific medication monitoring plans in clinical practice to study disease progression caused by the occurrence of drug resistance.

Gastrointestinal stromal tumors: Fibrinogen levels are associated with prognosis of patients as blood-based biomarker

Improved prediction of prognosis for primary gastrointestinal stromal tumors (GISTs) after curative resection is an important goal in clinical practice. Coagulation factor of fibrinogen may inform prognosis of tumor patients as blood-based biomarker. Here, we aimed to analyze the prognostic value of fibrinogen levels in patients with GIST and to explore potential threshold of fibrinogen on postoperative clinical outcome.A retrospective study was performed including data from 91 patients with newly diagnosed GISTs who underwent curative resection. Patients were followed-up for a median period of 2 years. Cox regression and competing risk analysis were applied to study the association between fibrinogen and risk of death or recurrence. Smoothing plot and threshold effect analysis were applied to learn the relationship further and explore potential threshold.High levels of fibrinogen are associated with decreased overall survival (OS) and recurrence free survival (RFS) in patients with GISTs. We discovered a nonlinear relationship between levels of fibrinogen and the risk of death or recurrence. Further, we detected a threshold for fibrinogen (3.7 g/L) on the prognosis of GISTs patients. When fibrinogen was above the inflection point, the increase in fibrinogen levels was strongly associated with increase in the risk of death or recurrence.Elevated fibrinogen can serve as an independent prognostic biomarker for a worse clinical outcome in GIST patients.

Blood-Based Biomarkers Are Associated with Disease Recurrence and Survival in Gastrointestinal Stroma Tumor Patients after Surgical Resection

Background

Inflammatory blood count biomarkers may improve recurrence risk stratification and inform long-term prognosis of cancer patients. Here, we quantify the prognostic impact of blood-based biomarkers on recurrence risk and long-term survival in a large cohort of gastrointestinal stroma tumor (GIST) patients after curative surgery.

Methods

One-hundred-forty-nine consecutive GIST patients were followed-up for a median period of 4.8 years. Local recurrence, distant metastasis, and death occurred in 9, 21, and 31 patients, respectively. Time-to-event and competing risk analysis were applied to study the association between haemoglobin (Hb) level, white blood cell count (WBC), neutrophil/lymphocyte ratio (NLR), derived NLR (dNLR), lymphocyte/monocyte ratio (LMR), and platelet/lymphocyte ratio (PLR) with risk of local or distant recurrence (RR), recurrence free survival (RFS), and overall survival (OS).

Results

A low Hb (p = 0.029), and elevations in the parameters WBC (p = 0.004), NLR (p = 0.015) and dNLR (p = 0.037) were associated with a poor OS in GIST patients in multivariate analysis. Moreover, a low Hb (p = 0.049) and an elevated WBC (p = 0.001), NLR (p = 0.007), dNLR (p = 0.043) and PLR (p = 0.024) were independently associated with decreased RFS after adjusting for Miettinen score. However, only an increase of dNLR/NLR showed a significant association to higher RR (p = 0.048). Inclusion of NLR or PLR to Miettinen risk score did not reasonably improve the clinical risk prediction of 2-year RFS.

Conclusion

Low Hb, elevated WBC, elevated dNLR, and elevated PLR are independent prognostic factors for a worse clinical outcome in GIST patients after curative resection.

Prediction of Tumor Recurrence in Patients with Non-Gastric Gastrointestinal Stromal Tumors Following Resection according to the Modified National Institutes of Health Criteria

Background/Aims

Few studies have investigated the prognosis of non-gastric gastrointestinal stromal tumors (GISTs) under the modified National Institutes of Health (NIH) consensus criteria in Korea. This study aims to clarify the clinical usefulness of the modified NIH criteria for risk stratification.

Methods

From January 2000 through October 2012, 88 patients who underwent curative resection for primary GISTs were included in this study. The enrolled patients were stratified to predict recurrence by the original NIH criteria and modified NIH criteria.

Results

In all, 88 patients had non-gastric GISTs, including 82 and 6 patients with GISTs of the small intestine and colorectum, respectively. The mean age was 57.3±13.0 years, and the median follow-up duration was 3.40 years (range, 0.02-12.76 years). All patients who were placed in the intermediate-risk category according to the original NIH criteria were reclassified into the high-risk category according to the modified NIH criteria. Therefore, the proportion of cases in the intermediate-risk category declined to 0.0% from 25.0% (22/88), and the proportion of cases in the high-risk category increased to 43.2% (38/88) from 18.2% (16/88) under the modified NIH criteria. Among the 22 reclassified patients, 6 (27.3%) suffered a recurrence during the observational period, and the recurrence rate of high-risk category patients was 36.8% (14/38).

Conclusions

Patients in the high-risk category according to the modified NIH criteria had a high GIST recurrence rate. Therefore, the modified NIH criteria are clinically useful in selecting patients who need imatinib adjuvant chemotherapy after curative surgical resection.

At the crossroads of molecular biology, pathology and the clinic

This article outlines some of the highlights of the fourth ESMO Conference on Sarcoma and GIST, a broad-based international multidisciplinary educational meeting that focused on recent advances made in molecular biology and genetics, and the state-of-the art diagnosis and treatment of soft tissue sarcoma and gastrointestinal stromal tumors.

Gastrointestinal stromal tumors

INTRODUCTION

The gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the intestinal tract, known to be refractory to conventional chemotherapy or radiation. Its pathogenesis is defined by mutations within the KIT and PDGFRA gene, which constitutively activate KIT and PDGFRA oncoproteins, and serve as crucial diagnostic and therapeutic targets.

DISCUSSION

Besides surgery, therapy with imatinib mesylate, which inhibits KIT kinase activity, represents the other cornerstone for the treatment of GIST. Still, the only curative option for GIST is given after complete surgical removal even in a metastatic setting, but recurrence is common, and the risk can be defined by surgical factors like incomplete resection, intraperitoneal rupture, or bleeding and tumor associated factors like tumor size, mitotic index, or localization.

CONCLUSION

Consequently, adjuvant therapy with imatinib mesylate or other tyrosine kinase inhibitors is recommended for high-risk patients after complete resection. For unresectable and advanced GIST, a partial response or stable disease can be achieved in about 80% of patients with imatinib mesylate.

Targeted therapies in soft tissue sarcomas

Soft tissue sarcomas are rare cancers but because of their association with characteristic chromosomal translocations and activating mutations they may be particularly susceptible to molecularly targeted therapies. Gastrointestinal stromal tumour (GIST) became the paradigm for targeted therapy in solid tumours owing to the success of imatinib, which has transformed the prognosis in this disease. Translocation-driven tumours have proved harder to target, but the impact of fusion proteins on gene expression is beginning to be understood and may also reveal new targets for therapy, such as insulin-like growth factor 1 receptor, now that effective inhibitors have been discovered. Angiogenesis inhibition also appears to be a promising area for research in sarcomas and many new targets are emerging at the same time as agents capable of investigating them in the clinic are being developed. It is not unrealistic to hope that targeted therapies will play an increasing role in the management of sarcomas in the near future.

Gastrointestinal stromal tumors: the histology report

Gastrointestinal stromal tumors (GISTs) represent a mesenchymal neoplasm occurring primarily in the gastrointestinal tract, and showing differentiation toward the interstitial cell of Cajal. Its incidence is approximately 15 case/100,000/year. Stomach and small bowel are the most frequently affected anatomic sites. GIST represents a morphological, immunophenotypical and molecular distinct entity, the recognition of which has profound therapeutic implications. In fact, they have shown an exquisite sensitivity to treatment with the tyrosine kinase inhibitor imatinib. Diagnosis relies upon morphology along with immunodetection of KIT and/or DOG1. When dealing with KIT negative cases, molecular analysis of KIT/PDGFRA genes may help in confirming diagnosis. Molecular evaluation of both genes are in any case recommended as mutational status provides key predictive information. Pathologists also play a key role in providing an estimation of the risk of biological aggressiveness, which is currently based on anatomic location of the tumor, size, and mitotic activity.

Added value of molecular targeted agents in oncology

The treatment of certain cancers has been revolutionised in recent years by the introduction of novel drugs designed to target specific molecular factors implicated in tumour growth. Notable examples include trastuzumab, a humanized monoclonal antibody (mAb) against human epidermal growth factor receptor (HER)-2 in women with HER2-positive breast cancer; rituximab, an anti-CD20 mAb in patients with non-Hodgkin's lymphoma; imatinib, a tyrosine kinase inhibitor in KIT-positive gastrointestinal stromal tumours and sunitinib, another tyrosine kinase inhibitor, in metastatic renal cell carcinoma. For regulatory reasons, new molecular targeted agents are first evaluated in advanced and metastatic disease, wherein they prolong survival. However, their most profound impact has been observed in the adjuvant setting, where they may contribute to curative therapy rather than mere palliation. Expansion in the use of molecular targeted therapies will have important cost implications for health care systems. Although expensive, on a monthly basis, molecular targeted therapies may not be more costly than treatments for other major chronic diseases, especially considering the contribution of cancer to the global disease burden, the associated socioeconomic costs and the long-term benefits of therapy. Nevertheless, the use of these agents must be optimised, in part using molecular biomarkers associated with drug response.

Imatinib: as adjuvant therapy for gastrointestinal stromal tumour

Imatinib is a protein-tyrosine kinase inhibitor with antitumour effects in patients with gastrointestinal stromal tumour (GIST) that is indicated for the treatment of unresectable and/or metastatic GIST and as adjuvant therapy in patients with KIT-positive GIST. Imatinib binds to and inhibits KIT and platelet-derived growth factor receptor (PDGFR)-α tyrosine kinases, interfering with their downstream tumourogenic processes. Cell lines with KIT mutations that are common in patients with GIST were sensitive to imatinib at low in vitro concentrations. Patients with exon 11 KIT mutations were significantly more likely to have partial tumour responses and longer overall survival (OS) and were significantly less likely to have progression of disease than patients with exon 9 KIT mutations or no detectable KIT or PDGFR mutations. In a large (n > 700) randomized, double-blind, placebo-controlled, multinational trial (ACOSOG [American College of Surgeons Oncology Group] Z9001), patients who received 1 year of adjuvant treatment with oral imatinib 400 mg/day after surgical resection of GIST had significantly longer recurrence-free survival than placebo recipients, with an overall hazard ratio of 0.35 (95% CI 0.22, 0.53) [primary endpoint]. At the time of reporting, there was no significant between-group difference in OS. In patients with GIST who received adjuvant imatinib in this trial, adverse events were mostly of mild or moderate severity; the imatinib treatment group had an almost 2-fold higher rate of US National Cancer Institute Common Toxicity Criteria grade 3 or 4 adverse events than the placebo group.

Neoadjuvant and adjuvant imatinib treatment in gastrointestinal stromal tumor: current status and recent developments

PURPOSE OF REVIEW

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract and is a paradigm of targeted therapy for solid tumors. Elucidation of the biology of GIST enabled use of imatinib, which revolutionized the prognosis of advanced GIST. Whereas surgical resection continues to be the standard of care for primary GIST, judicious and individualized use of adjuvant and neoadjuvant imatinib may enhance the potential for cure in select patients.

RECENT FINDINGS

Prospective trials utilizing adjuvant and neoadjuvant imatinib have established the safety and efficacy of these modalities adjunct to surgical resection. Correlative tissue studies derived from these trials have examined gene expression patterns, metabolic and radiographic response, and apoptosis during the first few days of imatinib therapy. As appropriate use of adjuvant and neoadjuvant imatinib requires proper patient selection, development of a predictive nomogram, and advances in mutational analysis represent progress toward individualized care.

SUMMARY

Imatinib is well tolerated and beneficial as adjuvant and neoadjuvant therapy, but its utility in these settings continues to be refined. The greatest benefit will derive from an individualized approach that considers multiple patient, drug, and tumor characteristics to assess risk and likelihood of benefit for each patient.

A prospective epidemiological study of new incident GISTs during two consecutive years in Rhône Alpes region: incidence and molecular distribution of GIST in a European region

Background:

Preliminary data indicate that the molecular epidemiology of localised gastrointestinal stromal tumour (GIST) may be different from that of advanced GIST. We sought to investigate the molecular epidemiology of sarcomas, including GIST, in the Rhone-Alpes region in France.

Patients and methods:

A prospective and exhaustive study in the Rhone-Alpes Region in France to assess the precise incidence of primary sarcomas with systematic centralised pathological review and molecular analysis was conducted for 2 consecutive years.

Results:

Among 760 patients with a confirmed diagnosis of sarcoma, 131 (17%) had a GIST. The majority of patients had gastric primaries (61%). Mutational analysis could be performed in 106 tumour samples (74%), and 71 (67%) had exon 11 mutations. PDGFRA mutations were found in 16% of cases, which is twice as high as previously reported for advanced GIST.

Conclusion:

Data indicate that PDGFRA mutations in localised GIST may be twice as high as what was previously reported in patients with advanced disease. This finding may have important consequences for patients offered adjuvant imatinib, although most of these tumours are in the low-risk group.

Gastrointestinal stromal tumor: a bridge between bench and bedside

Gastrointestinal stromal tumor (GIST) is considered to be driven by a gain-of-function mutation in the KIT or PDGFRA gene. Cure can be obtained only by complete surgical removal of the GIST; however, imatinib, an inhibitor of KIT and PDGFRA, is indicated for advanced, recurrent, and/or metastatic GISTs. Imatinib exhibited remarkable clinical effects on advanced GISTs, with substantial tolerability. Its efficacy greatly depends on the genotype of GIST. The drug, however, met intrinsic or acquired resistance during the treatment, of which the molecular mechanisms were mostly dependent on the genotype of GIST, including primary mutations or secondary mutations in the kinase domains of the corresponding target genes, respectively. Although sunitinib had substantial effects on imatinib-resistant GIST, this drug also encountered primary or secondary resistance depending on the genotype. Thus, advanced GIST may require multidisciplinary treatment. Because resistance mechanisms show some regularity, it is hoped that, in the near future, we may be able to develop a new drug to which resistance does not occur easily, based on scientific evidence.