Multidisciplinary care of gastrointestinal stromal tumour: a review and a proposal for a pre-treatment classification

Gastrointestinal stromal tumour (GIST): British Sarcoma Group clinical practice guidelines

BACKGROUND

British Sarcoma Group guidelines for the management of GIST were initially informed by those published by the European Society of Clinical Oncology. This update was written by a group of experts to includes a discussion of the highlight improvements in our knowledge of the disease and recent treatment developments. The guidelines include sections on Incidence, Aetiology, Diagnosis, including risk assessment, Treatment and Follow-up.

METHODS

A careful review of the literature was performed to ensure that wherever possible recommendations are supported by the results of clinical trials or substantive retrospective reports. Areas of uncertainty are indicated appropriately.

CONCLUSION

Guidelines represent a consensus view of current best clinical practice. Where appropriate, key recommendations are given and the levels of evidence and strength of recommendation gradings are those used by the European Society for Medical Oncology (ESMO).

Advances of endoscopic and surgical management in gastrointestinal stromal tumors

As one of the most common mesenchymal malignancies in the digestive system, gastrointestinal stromal tumors (GISTs) occur throughout the alimentary tract with diversified oncological characteristics. With the advent of the tyrosine kinase inhibitor era, the treatment regimens of patients with GISTs have been revolutionized and GISTs have become the paradigm of multidisciplinary therapy. However, surgery resection remains recognized as the potentially curative management for the radical resection and provided with favorable oncological outcomes. The existing available surgery algorithms in clinical practice primarily incorporate open procedure, and endoscopic and laparoscopic surgery together with combined operation techniques. The performance of various surgery methods often refers to the consideration of risk evaluation of recurrence and metastases; the degree of disease progression; size, location, and growth pattern of tumor; general conditions of selected patients; and indications and safety profile of various techniques. In the present review, we summarize the fundamental principle of surgery of GISTs based on risk assessment as well as tumor size, location, and degree of progress with an emphasis on the indications, strengths, and limitations of current surgery techniques.

Preoperative imaging of gastric GISTs underestimates pathologic tumor size: A retrospective, single institution analysis

BACKGROUND

How well imaging size agrees with pathologic size of gastric gastrointestinal stromal tumors (GISTs) is unknown. GIST risk stratification is based on pathologic size, location, and mitotic rate. To inform decision making, the size discrepancy between imaging and pathology for gastric GISTs was investigated.

METHODS

Imaging and pathology reports were reviewed for 113 patients. Bland-Altman analyses and intraclass correlation (ICC) assessed agreement of imaging and pathology. Changes in clinical risk category due to size discrepancy were identified.

RESULTS

Computed tomography (CT) (n = 110) and endoscopic ultrasound (EUS) (n = 50) underestimated pathologic size for gastric GISTs by 0.42 cm, 95% confidence interval (CI): (0.11, 0.73), p = 0.008 and 0.54 cm, 95% CI: (0.25, 0.82), p < 0.001, respectively. ICCs were 0.94 and 0.88 for CT and EUS, respectively. For GISTs ≤ 3 cm, size underestimation was 0.24 cm for CT (n = 28), 95% CI: (0.01, 0.47), p = 0.039 and 0.56 cm for EUS (n = 26), 95% CI: (0.27, 0.84), p < 0.0001. ICCs were 0.72 and 0.55 for CT and EUS, respectively. Spearman's correlation was ≥0.84 for all groups. For GISTs ≤ 3 cm, 6/28 (21.4% p = 0.01) on CT and 7/26 (26.9% p = 0.005) on EUS upgraded risk category using pathologic size versus imaging size. No GISTs ≤ 3 cm downgraded risk categories. Size underestimation persisted for GISTs ≤ 2 cm on EUS (0.39 cm, 95% CI: [0.06, 0.72], p = 0.02, post hoc analysis).

CONCLUSION

Imaging, particularly EUS, underestimates gastric GIST size. Caution should be exercised using imaging alone to risk-stratify gastric GISTs, and to decide between surveillance versus surgery.

Evaluation of Ki67 Index in Endoscopic Ultrasound-Guided Fine Needle Aspiration Samples for the Assessment of Malignancy Risk in Gastric Gastrointestinal Stromal Tumors

BACKGROUND

The risk of malignancy in resected gastrointestinal stromal tumors (GISTs) depends on tumor size, location, and mitotic index. Reportedly, the Ki67 index has a prognostic value in resected GISTs. We aimed to analyze the accuracy of endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) samples with reference to Ki67 index, using surgical specimens as the gold standard.

METHODS

Fifty-five patients who underwent EUS-FNA followed by surgical resection for gastric GISTs were retrospectively analyzed. Patients' age and sex; tumors' size and location; mitotic index, cell type, cellularity, pleomorphism, presence of ulceration, hemorrhage, necrosis, mucosal or serosal invasion, growth pattern, and Ki67 index based on pathology were investigated.

RESULTS

Location in fundus, ulceration, hemorrhage, mucosal invasion, and Ki67 index in surgical specimens were significant in predicting high-risk groups (p < 0.05) on univariate analysis. Frequency of bleeding (p = 0.034) and the Ki67 index (p = 0.018) were the only independent significant factors in multivariate analysis. The optimal cutoff level of Ki67 was 5%, with 88.2% sensitivity and 52.8% specificity (p = 0.021). The mean Ki67 index was lower in EUS-FNA samples than in surgical specimens (2% [1-15] versus 10% [1-70], p = 0.001). The rank correlation coefficient value of Ki67 was 0.199 (p = 0.362) between EUS-FNA and surgical samples and showed no reliability for EUS-FNA samples.

CONCLUSION

The Ki67 index in resected specimens correlated with high-risk GISTs, although it had no additive value to the current criteria. The Ki67 index in EUS-guided FNA samples is not a reliable marker of proliferation in GISTs.

Short-term outcomes after duodenal surgery for mesenchymal tumors: a retrospective analysis from a single tertiary referral center

Duodenal resections are sometimes necessary for radical surgery. We analyzed technical aspects and post-operative outcomes in patients with RPS and GIST involving duodenum. We identified patients who underwent duodenal resection for RPS and GIST at our Institute between 2000 and 2016. Clinical, pathological and treatment variables were analyzed. Thirty patients were treated: 15 for GIST, 15 for RPS. Sixteen duodenal wedge resections (WR) and 14 segmental resections (SR) were performed. Multi-organ resection was frequently performed (63.4%). Median time to flatus was 3 days (range 1-6), to oral refeeding 4.5 (range 2-15). Overall postoperative morbidity rate was 53% (16/30): Clavien Dindo grade ≤ II: 10; duodenum-related complication rate was 33% (10/30), Clavien Dindo grade ≤ II: 9. Morbidity rates were higher in SR than WR. Duodenal resections for RPS and GIST have significant morbidity rate and whenever it is possible, WR is preferable to SR because of the lower morbidity rate.

Preoperative monocyte-to-lymphocyte ratio predicts recurrence in gastrointestinal stromal tumors

BACKGROUND AND OBJECTIVES

Several inflammation markers were found to have a prognostic value in cancer. We investigated the significance of preoperative white cell ratios in determining gastrointestinal stromal tumors (GISTs) outcome.

METHODS

Clinicopathological features of patients who underwent surgery for GIST were reviewed. The following peripheral blood inflammation markers were calculated: neutrophil-lymphocyte ratio (NLR), monocyte-lymphocyte ratio (MLR), platelet-lymphocyte ratio (PLR), neutrophil-white blood cell ratio (NWR), lymphocyte-white cell ratio (LWR), monocyte-white cell ratio (MWR), and platelet-white cell ratio (PWR).

RESULTS

We analyzed 127 patients. Three- and five-year disease-free survival (DFS) were 89.7% and 86.9%, respectively. The univariate analysis selected tumor diameter (P = 0.003), gastric location ( P = 0.024), cell type ( P = 0.024), mitosis ( P < 0.001), MLR ( P = 0.014), NLR ( P = 0.016), and PLR ( P = 0.001) as the factors associated to DFS. The independent prognostic factors for DFS were mitosis ( P = 0.001), NLR ( P = 0.015), MLR ( P = 0.015), and PLR ( P = 0.031), with MLR showing the highest statistical significance and hazard ratio (HR) value. MLR, NLR, and PLR were the only prognostic factors in the subgroup of patients with moderate to high Miettinen's risk class. A high value of MLR was associated with reduced DFS.

CONCLUSION

MLR, NLR, and PLR are independent prognostic factors for DFS in GISTs. We first demonstrated the role of MLR as a predictor of recurrence in GIST. Its inclusion into clinical management may improve the recurrence estimation.

Additional malignancies in patients with gastrointestinal stromal tumors (GIST): incidence, pathology and prognosis according to a time of occurrence-based classification

BACKGROUND

The aim of the study is to clarify if a classification based on the time of occurrence of associated malignancies in GIST patients can help in the understanding of the clinical controversies observed in these patients.

METHODS

We retrospectively reviewed all the patients diagnosed with GIST tumors between January 1999 and October 2016. They were divided into GIST patients associated with other tumors (A-GIST) and those not associated (NA-GIST). A-GIST patients were also divided into four types according to the proposed classification.

RESULTS

Of 104 GIST patients, 32 (30.7%) (A-GIST group) had at least one additional primary malignancy. The most frequent location of the associated malignancy was the GI tract (26%). Compared to NA-GIST, A-GIST were more often asymptomatic with a lower risk of recurrence. The main cause of death in NAGIST was GIST itself, being associated tumors the main cause of death in A-GIST group. No differences were found in DFS and OS between A-GIST and NA-GIST.

CONCLUSIONS

The use of the proposed classification classifies GIST patients with associated malignancies in different subtypes that differ substantially in terms of incidence, type of neoplasms associated, cause of the association and prognosis.

Clinical and pathological features of "small" GIST (≤2 cm). What is their prognostic value?

INTRODUCTION

Small GIST (<2 cm) are tumors whose biological behavior is benign and frequently involutes. Despite their increasing incidence, few studies have addressed the characteristics of these GIST. The aim of this work is to clarify the management of this entity.

PATIENTS AND METHOD

The characteristics of ≤2 cm GIST were initially described, and then compared with those >2 cm. This series comprises 104 patients and they were divided according to tumor size in 4 groups: tumors which are ≤2 cm (group 1, G1), >2 and ≤ 5 cm (G2), >5 and ≤ 10 cm (G3) and >10 cm (G4).

RESULTS AND DISCUSSION

Most of small GIST were asymptomatic and incidental, and were located in the stomach. There is an association between patients with associated tumors and asymptomatic GIST. A high overall mortality rate of up to 40% is observed being disease-specific mortality 4.5%. The disease-specific mortality increases proportionally with size. The overall survival (OS) at 5 years are lower for both <2 cm (61%) and >10 cm (53%) than the rest (85-91%). When analyzing the impact of tumor association on <2 cm GIST, we observed that the OS of patients with non-associated tumors was much higher than in the associated ones (90% vs 32% at 5 years, respectively), while no differences were observed in the disease specific survival.

CONCLUSIONS

Small GIST are tumors that are very often incidentally discovered in the course of complementary examinations. Its prognosis is very good, but it depends on the associated tumor.

UK clinical practice guidelines for the management of gastrointestinal stromal tumours (GIST)

BACKGROUND

Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues. Gastrointestinal stromal tumour (GIST) is the commonest STS and arises within the wall of the gastrointestinal (GI) tract. While most GISTs occur in the stomach they do occur in all parts of the GI tract. As with other STS, it is important that GISTs are managed by expert teams, to ensure consistent and optimal treatment, as well as recruitment to clinical trials, and the ongoing accumulation of further knowledge of the disease. The development of appropriate guidance, by an experienced panel referring to the evidence available, is therefore a useful foundation on which to build progress in the field.

METHODOLOGY

British Sarcoma Group guidelines for the management of GIST were initially developed by a panel of physicians experienced in the management of GIST. This current version has been updated and amended with reference to other European and US guidance. We have received input from representatives of all diagnostic and treatment disciplines as well as patient representatives. Levels of evidence and strength of recommendation gradings are those used by ESMO adapted from those published by the Infectious Disease Society of America.

CONCLUSIONS

The guidelines cover aetiology, genetics and underlying molecular mechanisms, diagnosis and initial investigations, staging and risk stratification, surgery, neoadjuvant and adjuvant therapy, the management of advanced disease and follow-up. The importance of mutational analysis in guiding treatment is highlighted, since this can indicate the most effective treatment and avoid administration of ineffective drugs, emphasising the need for management in specialist centres.

Surgical treatment of gastrointestinal stromal tumour of the rectum in the era of imatinib

BACKGROUND

Gastrointestinal stromal tumours (GISTs) of the rectum often require radical surgery to achieve complete resection. This study investigated the management and outcome of surgery for rectal GISTs and the role of imatinib.

METHODS

A cohort study was undertaken of patients identified from a database at one tertiary sarcoma referral centre over a continuous period, from January 2001 to January 2013.

RESULTS

Over 12 years, 19 patients presented with a primary rectal GIST. Median age was 57 (range 30-77) years. Neoadjuvant imatinib was used in 15 patients, significantly reducing mean tumour size from 7·6 (95 per cent c.i. 6·1 to 9·0) to 4·1 (2·8 to 5·3) cm (P < 0·001). Nine of these patients underwent surgical resection. Imatinib therapy enabled sphincter-preserving surgery to be undertaken in seven patients who would otherwise have required abdominoperineal resection or pelvic exenteration for tumour clearance. Neoadjuvant imatinib treatment also led to a significant reduction in mean(s.d.) tumour mitotic count from 16(16) to 4(9) per 50 high-power fields (P = 0·015). Imatinib was used only as adjuvant treatment in two patients. There were three deaths, all from unrelated causes. Eleven of the 13 patients who underwent resection were alive without evidence of recurrence at latest follow-up, with a median disease-free survival of 38 (range 20-129) months and overall survival of 62 (39-162) months.

CONCLUSION

The use of neoadjuvant imatinib for rectal GISTs significantly decreased both tumour size and mitotic activity, which permitted less radical sphincter-preserving surgery.

Endoscopic ultrasound-guided fine needle tissue acquisition biopsy samples do not allow a reliable proliferation assessment of gastrointestinal stromal tumours

BACKGROUND

Current prognostication of gastrointestinal stromal tumours is validated on/applies to resected tumours, mainly because surgery is recommended whenever possible. However, pre-treatment prognostication is increasingly warranted, considering the follow-up strategy recently admitted for expectedly low-risk tumours and the possible distinctive molecular features/spontaneous regression of some small cases.

AIMS

To investigate whether endoscopic ultrasound-guided fine-needle tissue acquisition-biopsies reflect prognosticators of resected gastrointestinal stromal tumours, for possibly developing reliable pre-treatment prognostic criteria.

METHODS

The applicability/reliability of mitotic index/5mm(2) and MIB1 proliferative index/1000 cells were tested in 35 endoscopic ultrasound-guided fine-needle tissue acquisition-biopsies diagnosed as gastrointestinal stromal tumour, subsequently resected without intervening therapy, consecutively collected in thirty months. Size and mitotic/proliferative indexes were compared with resection specimens. The feasibility of bioptic genotyping was also tested.

RESULTS

35 patients were studied (45.7% males; mean age 61.6 years, range 26-83 years). Mitotic/proliferative indexes were determinable in 68.6%/88.6% of biopsies, respectively; they were nevertheless underestimated, as happened with endoscopic ultrasound-determined tumour size. Bioptic genotyping revealed reliable.

CONCLUSIONS

Endoscopic ultrasound-guided fine-needle tissue acquisition does not reliably reflect gastrointestinal stromal tumours' proliferation and size. Alternative parameters should be validated for a pre-surgical prognostic classification. Considering the emerging potentially prognostic genetic markers in gastrointestinal stromal tumours, the reliability of bioptic genotyping is a promising result.

Localization of sunitinib, its metabolites and its target receptors in tumour-bearing mice: a MALDI-MS imaging study

BACKGROUND AND PURPOSE

The clinical effects of anti-angiogenic agents remain controversial. Therefore, elucidating the pharmacological properties of these compounds is a pivotal issue.

EXPERIMENTAL APPROACH

The effects of treatment with sunitinib on tumour and normal tissues of mice bearing C-26 adenocarcinoma cells were analysed by matrix-assisted laser desorption ionization MS imaging (MALDI-MSI). Expression of the key targets of sunitinib--angiogenic receptors--was studied by immunofluorescent labelling.

KEY RESULTS

MALDI-MS assays showed that sunitinib and its fragment ions were present throughout tumour and normal tissues. Major metabolites were identified in blood and solid tissues, while minor drug metabolites were detectable only in blood. Tumour growth and intratumour VEGF receptor-2 expressions were significantly reduced in sunitinib-treated mice, while the expression of the other targeted receptors, PDGF receptor -α or -β and fibroblast growth factor receptor-1, remained unaffected. Within tumour tissue, the close proximity of sunitinib metabolites to the precursor ion suggested in situ metabolism of the administered drug. There were intratumour areas where the signal intensity of sunitinib correlated with expression of VEGF receptor-2.

CONCLUSIONS AND IMPLICATIONS

This is the first study that demonstrates MALDI-MSI is a versatile platform to study the intratumour localization of an unlabelled anti-angiogenic drug. The combination of MALDI-MSI and immunofluorescence analysis can provide further insights into the molecular interaction of drug compounds and their targets within tumour tissue.

Prognostic factors for primary gastrointestinal stromal tumours: are they the same in the multidisciplinary treatment era?

PURPOSE

Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumour of the gastrointestinal tract. The introduction of tyrosine kinase inhibitors (TKIs) has lead to increasing use of combination of medical and surgical therapy. The aim of this study was to look at outcomes from a series of surgically treated GISTs and determine prognostic factors in the context of multimodal therapy.

METHODS

We analysed 104 single surgeon's patients with GIST. End points of the study were disease-specific survival (DSS), disease-free survival (DFS) and post-operative complications.

RESULTS

Three- and 5-year DSS rates were 96.7 and 94.6 %. On univariate analysis, clear resection margins were predictive of DSS. Patients with R2 resection had a worse prognosis (3-year DSS rate of 83.3 %; 5-year DSS rate of 62.5 %) compared to patients with R0 (3-year DSS rate of 98 %; 5-year DSS rate of 98 %) or R1 resection (3-year DSS rate of 100 %; 5-year DSS rate of 100 %) (R0 vs R1 vs. R2 p = 0.001). Pre-operative factors associated with R2 resection were clinical metastatic disease (p < 0.001), non-gastric tumour site (p = 0.002) and large tumour diameter (p = 0.031). Three- and 5-year DFS rates were 65.5 and 59.8 %. Serosal perforation (p = 0.013) and mitotic rate (p = 0.05) were found to be independently predictive of increased DFS. The presence of serosal perforation was associated with tumour site (p = 0.018), mitotic rate (p = 0.035), tumour diameter (p < 0.001), growth pattern (p = 0.007) and age (p = 0.040).

CONCLUSIONS

In the multidisciplinary management of GIST, serosal perforation may represent an additional predictor of recurrence along with mitotic rate. Complete macroscopic surgical resection is the most reliable prognostic factor, and an aggressive surgical approach should be advocated.