When I was in the surgical department as a junior doctor in a Borneo hospital, one of the most common types of abdominal surgeries I observed was the exploratory laparotomy. This procedure is performed to open up the abdomen to see more clearly the source of pathology in a way that may not be possible through medical imaging alone.
Hence, it is an “exploratory” surgery; however, surgeons usually have a pretty good idea about where the problem lies, and depending on what they find, they might immediately proceed to undertake subsequent intraoperative steps, such as surgical resection. Hence, on the preoperative surgical sheet, the surgical procedure would be listed as “Exploratory laparotomy + KIV (keep in view) cholecystectomy,” for example.
Surgeons in different parts of the world may choose to file their procedures differently (as protocols differ), but this nonetheless highlights a problem that is common to all surgical disciplines: the unknown. Every surgery entails certain risks, but the risks are compounded if surgeons do not have ample confidence in what they will find intraoperatively. Even when they do, there is still a risk that a mistake can happen, worsening the situation significantly.
In the specific case of gastrointestinal stromal tumors (GISTs), surgeons are often uncertain of the diagnosis until an exploratory laparotomy is performed. This is because GISTs may appear similar to leiomyomas and schwannomas upon endoscopy.
Read more about GIST etiology
So, is there anything we can do to better predict the occurrence of GIST prior to surgery?
Characteristics of GIST Patients
We can first look at some of the epidemiological data concerning patients who have been diagnosed with GIST. In the Scandinavian Journal of Gastroenterology, Ge and colleagues characterized the GIST patients seen in their study:
- The majority of GIST patients were Caucasian.
- The prevalence of GIST in the stomach was higher than in the small intestine.
- The tumor size across different age groups was 51-100 mm.
- Most patients had a mitotic index of 5/50HP or less.
- Almost 80% of the patients had undergone surgery.
- Survival rates were better among younger patients than older patients.
- Male patients with GISTs were at a higher risk of having poorer outcomes, compared to female patients with GISTs.
Lessons From a Case Study
In a study published in the Journal of Nippon Medical School, Yokoi and colleagues presented a case study on a patient who was diagnosed with GIST preoperatively.
The patient was a 39-year-old man who was incidentally found to have a gastric abnormality via upper gastrointestinal series (GIS). Initially, physicians suspected a cardiac ulcer.
Upper GIS revealed a protruding lesion of approximately 3.0 cm in size. There was central concavity near the greater curvature just under the esophagogastric junction. The central concavity mucous membrane was irregular while the peripheral mucosa was smooth.
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Gastroendoscopy likewise confirmed a protruding lesion around 3 cm in size. There was central concavity with irregular ulceration. Bridging folds were seen, prompting the surgeons to diagnose a gastric submucosal tumor.
A biopsy taken at the ulcer border demonstrated obliterated lamina muscularis mucosae caused by spindle-shaped cell proliferation. “Immunohistologic stainings revealed that the proliferating spindle cells were negative for α-smooth muscle actin (α-SMA) and S-100 protein, and positive for CD-34 and c-kit,” the research team wrote. On this basis, a diagnosis of GIST of uncommitted type was made.
This case study was reported in Japan in 2001, a time in which the concept of GIST was first gaining recognition. However, this case study is unique in that the surgeons decided to diagnose GIST based on preoperative findings. This was mostly aided by their decision to obtain a biopsy at the ulcer border; biopsies obtained in other regions of the stomach showed no changes in the epithelium surrounding the folds.
Other Influential Factors
In the Journal of Personalized Medicine, Lin and colleagues published a retrospective analysis of gastric subepithelial tumors (GSETs) that was conducted to better predict gastric GISTs preoperatively.
They analyzed patients with various forms of GSETs, including GISTs, leiomyomas, and schwannomas between 2-10 cm. The patients were divided according to the size of their GSET: 2-5 cm or 5-10 cm.
Based on recursive partitioning analysis, they discovered that the following combinations of factors carried a higher risk of a GIST diagnosis in the 2-5 cm group:
- Age ≤55, hemoglobin (Hb) ≥10.7, and necrosis on computed tomography (CT) scans.
- Age ≤55 and Hb <10.7.
- Age >55 and Hb <12.9.
- Age >55 and CT hetero/homogeneity.
For the 5-10 cm group, patients aged more than 55 years with positive or negative CT necrosis had a higher risk of a GIST diagnosis.
The authors of the study wrote that, generally, “GIST patients were older and presented with low Hb levels and tumor necrosis.”
Why go through all the trouble just to be better at diagnosing GIST preoperatively? There are a few important reasons.
First, we are still in the process of finding consensus on the most sensitive diagnostic tools for GIST, so any research in this direction helps. Second, knowing what kind of tumor needs to be resected and where it is located anatomically can aid surgeons to perform surgeries with the least amount of operation time and lower the risk of intraoperative complications. Third, diagnosing GIST intraoperatively allows surgeons to prescribe preoperative medications that may improve surgical outcomes.
Ge XY, Lei LW, Ge F, Jiang X. Analysis of risk factors of gastrointestinal stromal tumors in different age groups based on SEER database. Scand J Gastroenterol. 2019;54(4):480-484. doi:10.1080/00365521.2019.1604798
Yokoi K, Yamashita K, Tanaka N, et al. Gastrointestinal stromal tumor of the stomach diagnosed preoperatively. J Nippon Med Sch. 2001;68(5):435-441. doi:10.1272/jnms.68.435
Lin YN, Chen MY, Tsai CY, et al. Prediction of gastric gastrointestinal stromal tumors before operation: a retrospective analysis of gastric subepithelial tumors. J Pers Med. 2022;12(2):297. doi:10.3390/jpm12020297