Gastrointestinal Stromal Tumour (GIST) is the most common mesenchymal tumour of the gastrointestinal (GI) tract. It is thought to originate from the interstitial cells of Cajal, which are thought to play a role in the propagation of slow-wave gut peristalsis. While it is found throughout the gastrointestinal tract, the most common location is the stomach (50%–60%), followed by the small intestine (20%–25%), rectum (5%), and oesophagus (2%).[2–4] Clinical features may range from incidentally detected lesions to bleeding tumours or locally advanced disease. Approximately 10%–30% of GISTs are clinically malignant. All GISTs are considered to have the ability to metastasize. Fletcher et al characterised the malignant potential of GISTs and established primary tumour size and mitotic figures per high-power field as the best indicators to determine prognosis (Table 1).
Table 1 -
GIST risk assessment – Fletcher et al.
– Permission taken for reproduction of the table from Elsevier.
||Primary tumour size (cm)
||Mitotic count (per 50 HPF)
|Very Low Risk
||Any mitotic rate
Adapted from Fletcher et al.
The treatment of GISTs involves wide local excision to achieve negative margins. This is facilitated by the tumour's propensity to grow outward rather than submucosally. It is of note that a removal of all macroscopic disease, but microscopic margins are positive for tumour does not necessarily confer a worse prognosis as far as progression-free or overall survival is concerned. Recurrence in GISTs seems to be determined more by tumour size and mitotic index.
The tyrosine kinase receptor inhibitors imatinib and the second-line drug sunitinib are recommended in the adjuvant setting to prevent recurrence in high-risk lesions, even in microscopically margin-negative resection (R0 resection).[8,9]
Endoscopic submucosal dissection (ESD) has been proposed as an option for GIST extending up to the muscularis propria (MP) but with a size less than 2 cm, without extra-gastric extension and with less than 50% involvement in the MP layer. In patients without these features, the R1 rate is high and therefore likely inferior to laparoscopic resection, requiring either repeat procedures or intensive follow-up. We describe the first reported ESD case in Australia where a 2 cm antral GIST was completely excised, and the defect was closed using the Covidien Endo Stitch () suturing device.
2 Case presentation
A 68-year-old woman presented with an acute on chronic dyspeptic symptoms, including abdominal pain, postprandial nausea, bloating, and early satiety without any history of melena or weight loss. She did not have any history of previous malignancy or gastro-intestinal haemorrhage. The patient had no other significant past medical history.
Endoscopy revealed a 2 cm nodular lesion in the gastric antrum. Endoscopic ultrasound and computed tomography subsequently confirmed it as a 2 cm antral GIST (Fig. 1).
Since surgical resection by stapled wedge resection would have created a significant risk of gastric dysfunction post-procedure, the options of laparoscopy with freehand excision of the lesion and suture closure of the defect vs an endoscopic version of the same were discussed with the patient. As endoscopic resection was likely to involve an easier recovery for the patient, she elected to undertake this approach.
The procedure was performed under general anaesthesia. Olympus 190 and Olympus 180 Therapeutic scopes were used with disposable distal attachment, commonly known as the Olympus cap.
During ESD, the lesion was first localised, and the peri-tumoral region was dissected using an electrosurgical knife (Triangle Tip Knife J KD645L). Standard electrocautery/electrocoagulation was performed in conjunction with the Olympus TT knife. An Olympus cap was used to provide retraction of the lesion, and the dissection plane was kept a couple of millimetres (mm) from the lesion in order to ensure R0 resection. Normal saline was used for submucosal injection. The lesion was enucleated with preservation of the capsule (Fig. 1). From inside out, the dissected layers were the mucosal layer, sub-mucosal layer, and partly muscular layer with no involvement of the serosa layer.
To reduce the potential risk of full-thickness perforation due to thermal spread from electrocautery, the gastric defect was closed with a Figure-of-eight suture using the Apollo OverStitch Endoscopic suturing system (Fig. 2). The operating time was 132 mins.
The histopathology report was consistent with antral GIST, measuring 20 × 15 × 15 mm, with a well-demarcated encapsulated solid homogenous lesion with clear margins within the submucosal and MP planes. The mitotic figures were less than 1 per 5 mm square. Immunohistochemistry was positive for smooth muscle actin, CD34, CD117, DOG-1, and neurofilament. It was negative for S100, CAM5.2 and Desmin. Ki67 positivity was present in 3% of the tumour cells.
The patient was discharged from the hospital the day after an overnight observation in the general ward. There were no postoperative complications, and no intensive care unit monitoring was required. She commenced on a fluid diet from the night of surgery. She was discharged on oral proton pump inhibitors for a month at standard dose. Following this, she was not placed on adjuvant chemotherapy.
During the 6-month follow up, her symptoms were mostly resolved, and there was no weight loss. No other investigations were undertaken to examine the metastasis. A decision was made to repeat endoscopy only if the symptoms recurred.
Our patient had a tumour size of 2 cm in its maximum dimensions, with mitotic index < 1/5 mm, which put her in the very low-risk category according to Fletcher's criteria for risk assessment. She had no metastases and underwent R0 resection. Therefore, she has a good prognosis, and a multi-disciplinary team review is planned for follow-up with computed tomography at 1 year.
We have attached a brief video of the procedure to aid in visual conceptualisation, https://links.lww.com/MD-CASES/A18.
Mitsui et al in 2014 reported a series of 6 cases with non-exposed wall inversion surgery, where there was a complete resection rate of 100% in tumours with a mean diameter of 34 mm and mean operating time of 306 min, with no reported complications. Studies have shown acceptable results for larger tumours with a combined laparoscopic and endoscopic technique and lap-assisted endoscopic full-thickness resection.
In our approach to this patient with gastric GIST, we demonstrated the feasibility of conducting an endoscopic R0 resection on a gastric antral GIST of 2 cm in size. There are merits of the endoscopic approach in anatomically challenging areas such as the antrum or close to the esophagogastric junction, where surgical resection may be more morbid.
The limitation of this endoscopic approach is a comparatively high learning curve to attain skills in interventional endoscopy and the possible need for training or experience at a high-volume centre.
In the literature, the standard treatment for resectable GISTs without metastasis is upfront surgical excision. Laparoscopic excision, when feasible, has been shown to be effective in achieving R0 resection and good long-term oncological outcomes. Endoscopic techniques such as submucosal tunnelling endoscopic resection and laparo-endoscopic co-operative surgery have been reported in the literature for good clinical outcomes; however, further research is needed on their long-term effectiveness.[12–14]
The NIH-GIST Consensus Criteria aimed to develop a risk stratification system which has been supported by several studies, including six large cohort studies.
In addition to the above, several studies have attributed special importance to tumour rupture as an independent prognostic factor for size, site, or mitotic count. Joensuu developed a modified risk assessment system based on the NIH criteria which included tumour location and rupture as high-risk factors, in addition to the above.[15,16]
The introduction of imatinib (a tyrosine kinase inhibitor) has significantly changed the management of GIST, prolonging recurrence-free survival and increasing overall survival rates in metastatic or locally advanced cases.[17,18] Sunitinib and regorafenib are second-line tyrosine kinases and third-line multi-kinase inhibitors which are used in treatment failure with imatinib. However, these are adjuncts and cannot be expected to provide permanent cure without surgery.[12,19,20] In patients with high-risk GISTs who have completed tumour resection (R0 or R1), it is recommended to commence three years of adjuvant therapy with imatinib.
Supervisor: Michael Talbot.
Surgeon: Michael Talbot.
Writing – original draft: Susmit Prosun Roy, Aditya Thomas Benjamin.
Writing – review & editing: Susmit Prosun Roy, Aditya Thomas Benjamin.
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. Chun SY, Kim KO, Park DS, et al. Endoscopic submucosal dissection as a treatment for gastric subepithelial tumors that originate from the muscularis propria layer: a preliminary analysis of appropriate indications. Surg Endosc 2013;27:3271–9.
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