Accuracy and Feasibility of a Morpho-anatomical Classification Oriented Laparoscopic Resection of Gastric Stromal Tumors in Advanced Laparoscopic Surgery Center: a Prospective Cohort Study

Incidence rate of gastrointestinal stromal tumors (GIST) is 10-15 per million per year. Although very rare, it is the most common mesenchymal tumor of the gastrointestinal tract, and the stomach is the most common affected organ with up to 55.6%. Despite recent drug discoveries have greatly impacted the treatment, complete surgical resection with adequate safety margin is still the only potentially curative treatment for primary gastric GIST with no evidence of metastasis. As sarcomas in general, most GISTs also metastasize hematogenously to the liver, disseminate peritoneally, and rarely show lymph node metastasis, therefore systematic or prophylactic lymph node dissection is usually unnecessary; a pick-up sampling is considered sufficient when a perilesional lymph node enlargement is found. In addition to that, these tumors tend to be soft and friable. Therefore pseudocapsule may be tearing spontaneously or inadvertently during surgery and tumor cells can be disseminating intraperitoneally which results in increased risk for recurrence and decreased survival.

Considering these properties of the tumor, the goals of surgery for primary gastric GIST are handling the tumor with great care to avoid tumor rupture as well as performing a complete resection with a negative surgical margin and preserving the organ function as much as possible. This can be accomplished by the traditional open, or more recently by the various total or hybrid laparoscopic techniques. Despite laparoscopic surgical treatment of the GISTs had not been recommended owing to the higher risk of tumor rupture and subsequent peritoneal seeding in consensus meetings in the United States and Europe in 2004 and 2005 respectively, it has experienced a rapid and major evolutionary process and currently it is being advised to be a standard approach for gastric GISTs irrespective of its size or location.

In addition to achieve an R0 resection without a tear in the tumor, the most important issue for the laparoscopic gastric GIST surgery is the preserving the function and not to cause a stenosis in the stomach as much as possible. According to the morphologic characteristics of the tumor and the area in the three-dimensional anatomical configuration of the stomach that involved by the tumor, a lot of laparoscopic surgical scenarios can be produced. Among them, to achieve the best alternative which meets all above criteria the authors generated a morpho-anatomical classification system by which they could plan preoperatively to tailor the gastric resection and all operational requirements. This system was partly inspired by the TNM classification for GISTs and Japanese classification of gastric carcinoma, has long been used in authors' institution when planning a laparoscopic intervention for various gastric lesions in patients in whom an appropriate preoperative patient evaluation is needed. It is then specifically composed and standardized to adapt for primary gastric GISTs and it was being used for large tumors up to 10 cm.

The aims of the study was to demonstrate the feasibility of laparoscopic surgery for primary gastric GISTs larger than 5 cm, to find out the accuracy and practicality of the classification system in the development a preoperative strategy and the extent to which this strategy overlaps with the reality.