[Hereditary and non-hereditary syndromic gastointestinal stromal tumours]

Diagnosing gastrointestinal stromal tumors: The utility of fine-needle aspiration cytology versus biopsy

Background

Gastrointestinal stromal tumors (GIST) are mesenchymal tumors in the intestinal tract originating from a precursor to the interstitial cells of Cajal, which plays a role in gastric motility. The preoperative diagnosis of GIST may be very important for the surgical approach or the need for neoadjuvant treatment and is often done in conjunction with molecular testing.

Design

GISTs diagnosed in Stockholm between 1999 and 2019 with biopsy and/or fine‐needle aspiration (FNA) material were included. Clinical and tumor characteristics, as well as sample representability, ancillary techniques, diagnostic accuracy, and time to diagnosis, were categorized and compared.

Results

We identified 460 diagnostic samples from 347 patients, consisting of 212 biopsies and 248 FNAs. FNA cytology had a significantly (p < 0.05) better sample representability (92% vs. 77%), diagnostic accuracy (84% vs. 76%), and shorter time to diagnosis (4.5 vs. 12.3 days on average) in comparison with biopsies. In addition, ancillary techniques such as immunochemistry and molecular analysis for KIT and PDGFRA mutations could satisfactorily be performed on FNA materials.

Conclusions

There are advantages to both biopsy and FNA cytology in diagnosing GISTs. While the significantly shorter time to diagnosis for FNA cytology can be due to institutional differences, its many strengths make it both an accurate and time‐efficient method for preoperative diagnosis of GIST.

[Mesenchymal tumors and tumor-like lesions of the gastrointestinal tract: an overview]

Mesenchymal tumors and tumor-like lesions of the gastrointestinal (GI) tract are uncommon. They vary from reactive tumefactive lesions and benign neoplasms to highly aggressive sarcomas. Among them, GI stromal tumors (GISTs) are most common, followed, with less frequency, by smooth muscle and neurogenic tumors. The major challenge resides in correctly identifying GISTs and providing a comprehensive report (including risk assessment and genotyping) that represents the basis for an optimized surgical-oncological treatment and/or adjuvant therapy. On the other hand, the challenge of benign lesions is to find a good name (well understandable and reproducible diagnostic term) that helps avoid diagnostic ambiguity and prognostic uncertainty so that overprognostication and overtreatment can be prevented. Moreover, several recently described genetically defined benign and malignant entities need be correctly diagnosed due to their special "targeted" therapeutic options and to further characterize their clinicopathological and biological properties in the future. These recent entities include aggressive epithelioid inflammatory myofibroblastic sarcoma (ALK-RANBP2-driven), malignant gastrointestinal neuroectodermal tumor (EWSR1-ATF1/CREB-related), NTRK-rearranged neoplasms, and, most recently, colorectal NUTM1-rearranged sarcomas. This review highlights the major clinicopathological features of gastrointestinal mesenchymal lesions in light of recent developments.

Current Standard and Future Perspectives in the Treatment of Gastrointestinal Stromal Tumors

The origin of gastrointestinal stromal tumors (GIST) from interstitial cells of Cajal or their precursor cells has been understood since the early 1990s. The first mutations within the KIT-gene have been described in the late 1990s. Even though these mutations were the breakthrough of small molecular therapy, we still do not know the factors responsible for their malignant transformation. Until then, we can only speak of recurrence risk. This review gives an introduction on the current understanding of GIST and highlights the remaining questions for diagnosis, tumor progression, and treatment in progressive disease.

Surgical Management of Adolescents and Young Adults With Gastrointestinal Stromal Tumors: A US Population-Based Analysis

Importance

There is a dearth of population-based evidence regarding outcomes of the adolescent and young adult (AYA) population with gastrointestinal stromal tumors (GISTs).

Objectives

To describe a large cohort of AYA patients with GISTs and investigate the effect of surgery on GIST-specific survival (GSS) and overall survival (OS).

Design, Setting, and Participants

This retrospective cohort study of 392 AYA patients and 5373 older adult (OA) patients in the Surveillance, Epidemiology, and End Results (SEER) database with GISTs histologically diagnosed from January 1, 2001, through December 31, 2013, with follow-up through December 31, 2015, compared the baseline characteristics of AYA (13-39 years old) and OA (≥40 years old) patients and among AYA patients stratified by operative management. Kaplan-Meier estimates were used for OS analyses. Cumulative incidence functions were used for GSS analysis. The effect of surgery on survival was evaluated with a multivariable Fine-Gray regression model.

Exposure

Tumor resection.

Main Outcomes and Measures

GIST-specific survival and OS.

Results

This study included 392 AYA and 5373 OA patients diagnosed with GISTs (207 [52.8%] male AYA patients, 2767 [51.5%] male OA patients, 277 [70.7%] white AYA patients, and 3661 [68.1%] white OA patients). Compared with the OA patients, more AYA patients had small-intestine GISTs (139 [35.5%] vs 1465 [27.3%], P = .008) and were managed operatively (332 [84.7%] vs 4212 [78.4%], P = .003). Multivariable analysis of AYA patients found that nonoperative management was associated with a more than 2-fold increased risk of death from GISTs (subdistribution hazard ratio, 2.27; 95% CI, 1.21-2.25; P = .01). On subset analysis of 349 AYA patients with tumors of the stomach and small intestine, small-intestine location was associated with improved survival (OS: 91.1% vs 77.2%, P = .01; GSS: 91.8% vs 78.0%, P = .008). On subset analysis of 91 AYA patients with metastatic disease, operative management was associated with improved survival (OS: 69.5% vs 53.7%, P = .04; GSS: 71.5% vs 56.7%, P = .03).

Conclusions and Relevance

This study found that AYA patients are more likely to undergo surgical management than OA patients. Operative management is associated with improved OS and GSS in AYA patients, including those with metastatic disease.

[Soft tissue tumors in hereditary tumor syndromes]

Benign and malignant soft tissue tumors usually develop de novo without identifiable risk factors or predisposing conditions. However, in recent decades, soft tissue tumors have been increasingly recognized to be associated with diverse hereditary tumor syndromes as a consequence of germline mutations involving mainly tumor suppressor genes, but rarely also affecting proto-oncogenes. This is mainly the consequence of increasing application of modern genetic analysis tools, such as next-generation sequencing (NGS) and whole genome analyses. Syndrome-associated soft tissue tumors frequently show distinctive clinicopathological features and peculiarities that facilitate and potentially enhance their recognition and identification during routine surgical pathology practice. As it is not uncommon that pathologists are the first medical specialists to recognize a potential hereditary etiology of neoplastic diseases on the basis of specific pathological features, it is mandatory that pathologists be familiar with the main features that characterize those soft tissue tumors with inherited etiology, at least the most common and important of them. This review summarizes the main syndromes and their associated soft tissue tumors and discusses their characteristic pathological features that help in the recognition of hereditary syndromes.

[Advanced gastrointestinal stromal tumors : What role does surgery currently play in multimodal concepts?]

BACKGROUND

Gastrointestinal stromal tumors (GIST) have an incidence of 1-2/100,000 and thus constitute the most common mesenchymal neoplasm of the digestive tract. Their specific tumor biology with mutations in the protooncogenes c-KIT and PDGFR α acting as drivers of tumor growth facilitate targeted therapy with tyrosine kinase inhibitors. In this context, there are several specific indications for surgery in patients with advanced GIST.

OBJECTIVE

This article discusses the importance of surgery within multimodal therapeutic concepts for advanced GIST.

MATERIAL AND METHODS

The results of a selective literature search including own studies and case reports are presented.

RESULTS

For large GIST at unfavorable anatomical locations, which are not amenable to organ-sparing resection, neoadjuvant imatinib therapy is the standard upfront treatment prior to surgery in the case of imatinib-sensitive mutations in the c-KIT protooncogene. This usually reduces the extent of resection without increasing perioperative morbidity. In the metastatic setting, surgery can constitute a significant part of multimodal therapy in patients with a generalized response to drug therapy by resection of residual tumor masses, although there are no prospective studies to prove a beneficial effect on overall survival. In patients with focal progression on anti-proliferative therapy, local therapeutic measures can make an important contribution to multimodal tumor control. In patients with generalized progression, an operation should only be performed in highly selected cases with the goal of symptom control. Local ablative therapies, such as radiofrequency ablation (RFA), irreversible electroporation (IRE) and selective internal radiotherapy (SIRT) are a therapeutic option particularly for liver metastases.

CONCLUSION

Surgery plays an important role in the multimodal therapy of advanced GIST particularly in the neoadjuvant setting. Its role is more limited in metastatic stages where systemic treatment represents the frontline therapeutic approach.

Increased risk of additional cancers among patients with gastrointestinal stromal tumors: A population-based study

BACKGROUND

Most gastrointestinal stromal tumors (GISTs) are considered nonhereditary or sporadic. However, single-institution studies suggest that GIST patients develop additional malignancies at increased frequencies. It was hypothesized that greater insight could be gained into possible associations between GISTs and other malignancies with a national cancer database inquiry.

METHODS

Patients diagnosed with GISTs (2001-2011) in the Surveillance, Epidemiology, and End Results database were included. Standardized prevalence ratios (SPRs) and standardized incidence ratios (SIRs) were used to quantify cancer risks incurred by GIST patients before and after GIST diagnoses, respectively, in comparison with the general US population.

RESULTS

There were 6112 GIST patients, and 1047 (17.1%) had additional cancers. There were significant increases in overall cancer rates: 44% (SPR, 1.44) before the GIST diagnosis and 66% (SIR, 1.66) after the GIST diagnosis. Malignancies with significantly increased occurrence both before and after diagnoses included other sarcomas (SPR, 5.24; SIR, 4.02), neuroendocrine-carcinoid tumors (SPR, 3.56; SIR, 4.79), non-Hodgkin lymphoma (SPR, 1.69; SIR, 1.76), and colorectal adenocarcinoma (SPR, 1.51; SIR, 2.16). Esophageal adenocarcinoma (SPR, 12.0), bladder adenocarcinoma (SPR, 7.51), melanoma (SPR, 1.46), and prostate adenocarcinoma (SPR, 1.20) were significantly more common only before the GIST diagnosis. Ovarian carcinoma (SIR, 8.72), small intestine adenocarcinoma (SIR, 5.89), papillary thyroid cancer (SIR, 5.16), renal cell carcinoma (SIR, 4.46), hepatobiliary adenocarcinoma (SIR, 3.10), gastric adenocarcinoma (SIR, 2.70), pancreatic adenocarcinoma (SIR, 2.03), uterine adenocarcinoma (SIR, 1.96), non-small cell lung cancer (SIR, 1.74), and transitional cell carcinoma of the bladder (SIR, 1.65) were significantly more common only after the GIST diagnosis.

CONCLUSIONS

This is the first population-based study to characterize the associations and temporal relations between GISTs and other cancers by both site and histological type. These associations may carry important clinical implications for future cancer screening and treatment strategies.

Gastrointestinal stromal tumors in the setting of multiple tumor syndromes

PURPOSE OF REVIEW

Knowledge related to gastrointestinal stromal tumor (GIST) in the setting of nonhereditary and hereditary multiple tumor syndromes continues to expand. This review describes associations between sporadic GIST and second malignancies, as well as new contributions to our knowledge about hereditary GIST multiple tumor syndromes.

RECENT FINDINGS

Sporadic GIST patients have increased risk of developing synchronous/metachronous cancers, including nonhematologic and hematologic malignancies. Data suggest these associations are nonrandom, more prevalent in men and increase with age. New adrenal tumors have also been associated with nonhereditary Carney's triad. Meanwhile, understanding of the molecular basis of heritable GIST syndromes has improved. Several new familial GIST kindreds have been reported, including those with germline KIT and PDGFRα mutations. Knowledge about succinate dehydrogenase (SDH) deficiency and mutations in hereditary GIST syndromes has expanded. It is now known that neurofibromatosis-1-associated GISTs are SDHB-positive, whereas Carney-Stratakis syndrome-associated GISTs are SDHB-deficient with underlying germline mutations in SDH subunits A-D.

SUMMARY

Recognition and early diagnosis of GIST syndromes allows for improved comprehensive medical care. With additional understanding of the molecular pathogenesis of GIST multiple tumor syndromes, we can refine our screening programs and management of these patients and their families.

GISTogram: a graphic presentation of the growing GIST complexity

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. They have represented a paradigm of molecular-targeted therapies for solid tumors since the discovery of KIT mutations and KIT expression in GIST in 1998, which opened the way to the use of imatinib, a tyrosine kinase inhibitor able to inhibit the growth of cells expressing KIT-mutant isoforms. Since then, accumulating evidence revealed the rather heterogeneous nature of GIST, implying possible different diagnostic and therapeutic approaches for each specific case, leading to the development of drugs alternative to imatinib. In this brief commentary, we graphically represent the historical growing of genotype and phenotype evidence on GIST since 1998 in its increasing complexity by building up a graph, which we have called "GISTogram", that visually conveys most of GIST-characterizing features and the probability for each of them, either alone or in combination, to be observed in a single GIST case.

Gastrointestinal stromal tumors: diagnosis, therapy and follow-up care in Austria

Optimal treatment for patients suffering from gastrointestinal stromal tumors (GIST) is based on an interdisciplinary treatment approach. Austrian representatives of Medical and Surgical Oncology, Pathology, Radiology, Nuclear Medicine, Gastroenterology, and Laboratory Medicine issued this manuscript on a consensual base within the context of currently available and published literature. This paper contains guidelines and recommendations for diagnosis, therapy, and follow-up of GIST patients in Austria.

Inherited gastrointestinal stromal tumor syndromes: mutations, clinical features, and therapeutic implications

The discovery of underlying molecular genetic abnormalities in gastrointestinal stromal tumors (GISTs) such as activating mutations in the tyrosine kinase genes, KIT and platelet derived growth factor receptor-alpha (PDGFRA), has led to remarkable clinical advances in treatment. Small molecule inhibitors such as imatinib and sunitinib are known to inhibit the aberrantly activated KIT and PDGFRA receptor signaling and can lead to excellent clinical outcomes for patients with GIST. Though the majority of GISTs appear to arise sporadically, a number of families with high frequencies of GISTs have been reported and germline mutations have been identified. This review will highlight the various inherited mutations associated with familial GIST syndromes and describe how an improved understanding of these genetic syndromes has important clinical implications for future understanding of this heterogeneous disease.

Gastrointestinal stromal tumors: the role of the gastroenterologist in diagnosis and risk stratification

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that are best classified as sarcomas with variable aggressiveness. They are typically treated with surgical resection and adjuvant tyrosine kinase inhibitors or, for advanced/metastatic GISTs, with tyrosine kinase inhibitors alone. Gastroenterologists are often the first to detect GISTs and are, therefore, tasked with diagnosis and facilitation of early intervention. Diagnostic tools including various imaging techniques such as endoscopic ultrasound (EUS) and EUS-assisted tissue sampling are critical for an accurate diagnosis. In the case of small tumors, EUS-assisted resection or ligation techniques to treat asymptomatic small tumors have been described. This paper reviews current evidence for the diagnosis and management of GISTs, with an emphasis on the role of the gastroenterologist.

DOG1 and PKC-θ are useful in the diagnosis of KIT-negative gastrointestinal stromal tumors

Pathological diagnosis of gastrointestinal stromal tumors (GISTs) is based on histological findings and immunohistochemical demonstration of the KIT protein. KIT-negative GISTs account for ∼5% of cases and cause diagnostic difficulties. In the era of imatinib therapy, a correct diagnosis of GISTs is important for therapeutic reasons regardless of KIT expression. Recently, DOG1 has been introduced as an important diagnostic marker with high sensitivity and specificity. In this study, immunohistochemical staining for DOG1 and protein kinase C-θ (PKC-θ) in whole tissue sections, and mutation analyses for KIT and PDGFRA were performed in 26 KIT-negative GISTs. Tissue microarrays of 112 KIT-positive GISTs were used as controls. Overall, 25 KIT-negative GISTs were located in the stomach, and 1 in the rectum. The histological subtype was spindle in 12, epithelioid in 11, and mixed in 3 cases. The expression of DOG1 and PKC-θ was positive in 24 (92%) and in 25 cases (96%), respectively. All 26 KIT-negative GISTs expressed either DOG1 or PKC-θ, and 23 cases (89%) were positive for both makers. PKC-θ was positive in two cases (8%), which lacked both KIT and DOG1 expressions. Mutation analysis showed PDGFRA exon 18 mutation in 15 cases (58%) and KIT exon 11 mutation in 1 case (4%), whereas the remaining 10 cases (39%) were wild type for both KIT and PDGFRA. The expression of DOG1 and PKC-θ showed no significant difference in KIT-negative and KIT-positive GISTs (P=1.000 and P=0.167, respectively). Our findings suggest that both DOG1 and PKC-θ can be used in the diagnosis of KIT-negative GISTs and they show positive staining even in KIT-negative tumors, which are wild type for KIT and PDGFRA on mutation analysis.