gastrointestinal stromal tumors ( gist ) are the most common nonepithelial , mesenchymal neoplasms of the gastrointestinal tract . the tumor originates from the interstitial pacemaker cells of cajal accounting for less than 3% of all gastrointestinal neoplasms . these tumors were reported for the first time in 1983 as a separate entity from gastrointestinal smooth muscle and nerve sheath tumors . immunohistochemical studies have shown that up to 94% of gist tumors express cd117 , a c - kit protein , and 60% to 70% of gist tumors stain for cd34 . therefore , gist is now considered a completely separate entity from leiomyoma and leiomyosarcoma . gastrointestinal stromal tumors occur mainly in the stomach ( 40% to 70% ) followed by 15% each within the small and large bowel . these tumors spread by the hematogenous route , with the liver being the most common site of metastasis . tumor size > 5 cm and > 10 mitoses/50 high - power field have previously been correlated with a poor outcome . targeted therapies have been developed for gist tumors , but surgical resection remains the optimal first - line therapy . achieving a microscopically free margin appears to be the key element in surgical therapy , and due to the pattern of spread , extensive nodal dissection is not warranted . adjuvant therapy with imatinib ( gleevac ) , an agent that targets c - kit , is used in patients with aggressive tumor characteristics , based on the fletcher grade classification for malignant potential . more recently , minimally invasive approaches have been shown to be oncologically feasible and safe in other tumor sites , for example colon cancer as reported by jacob and salky . prior reports have suggested limiting the minimally invasive approach to those gastric gist tumors that are < 2 cm in size . the purpose of this study was to examine the efficacy of minimally invasive resection of gist tumors that are > 2 cm . the specific oncologic factors that were examined in this study were the ability to make the diagnosis of these gastric tumors by eus preoperatively , ability to achieve no spillage during surgery , ability to achieve complete tumor resection with negative margins , and the ability to perform safe intestinal anastamosis , if needed . a retrospective analysis of 4 patients who underwent laparoscopic resection of a suspected gastric gist at methodist dallas medical center in 2007 was performed after receiving institutional review board approval for the study . perioperative parameters measured included postoperative recovery including morbidity , mortality , and length of hospitalization . tumor histopathologic characteristics including size , mitotic activity , and violation of the pseudocapsule were also reviewed . an initial eus - guided fine - needle aspiration was performed as part of the staging . suspicion for gist was based on endoscopic features , such as an intact mucosa , a predominantly submucosal location , and in some cases , a pedunculated appearance . these patients also underwent a preoperative abdominal computed tomography ( ct ) scan as part of their diagnostic workup for assessment of the presence of distant metastases or local tumor invasion . the position of the patients in the operating room and location of the trocars for the laparoscopic resection of these tumors are shown in figure 1 . tumors > 5 cm and close to the esophagogastric junction were excluded from laparoscopic wedge resection but included in indications for laparoscopic operation with a small laparotomy ( so - called laparoscopic - assisted operation ) . distal gastrectomy was used for bulky tumors located in the middle or distal third of the stomach and wedge resection for peripheral gastric tumors ( table 1 ) . endoscopic ultrasound ( eus ) with preoperative workup characteristics and type of surgery performed the general principle used during the surgical approach is described as follows : the lesser sac was opened preserving the gastroepiploic vessels bilaterally extending up to the short gastric vessels and distally towards the duodenum by using a 5-mm harmonic scalpel . the stomach was then elevated out of the way by using a self - retaining retractor through a 5-mm port that was placed in the right lower quadrant . once the tumor was released from the area of the lateral , inferior , and medial aspect of these collateral vessels , attention was then paid to the stomach . a window was created underneath the stomach all the way to the splenic flexure that was mobilized , and the splenic flexure was taken down to mobilize the colon away from this tumor . we used an endo gia stapler ( 63.5 mm ) that was inserted through the umbilical port and fired across the greater curvature of the stomach , allowing the tumor to be freed from the stomach . the only attachments left on the tumor at this time were in the posterior aspect . the pneumoperitoneum was released , and the supraumbilical incision was extended for a length of approximately 6 cm to 7 cm , allowing us to gently deliver this tumor through the anterior abdominal wall . we ligated the posterior attachments and some small collateral vessels by using 5-mm ligature clips and 2 0 silk sutures . at this point , the mean age in this patient group was 58 ( range , 36 to 77 ) . all patients were accurately diagnosed preoperatively as having nonmetastatic gist by using eus and ct scan . seventy - five percent of tumors were considered to be gist by classic ultrasound appearance , and 50% were biopsy proven gastric gist tumors at the time of eus . mean tumor size was 10 cm ( range , 2.5 to 20 ) with distribution in the stomach as follows : 75% greater curvature and 25% antrum . two of the 4 gastric gist tumors were removed by wedge resection by using a laparoscopic stapler surrounding the tumor with a margin of normal tissue . the tumor was removed from the abdominal cavity by using a laparoscopic retrieval bag . in the other 2 cases , we used the harmonic scalpel to mobilize the greater curvature of the stomach to the duodenum . the distal stomach and proximal duodenum were divided to include the entire tumor . the midline port wound was extended to remove this specimen with the help of a laparoscopic retrieval bag . two of these tumors showed a high - grade and the other 2 showed a moderate - grade of differentiation . there was no intraoperative spillage in any patient , even with the largest tumor at 20 cm . we report herein on the efficacy of the minimally invasive assisted approach for the treatment of large gastric gist > 2 cm . this report suggests that preoperative selection by eus followed by a meticulous oncologic operative technique can result in complete resection of large gist with negative margins and no spillage . the guidelines for minimally invasive gatstrectomy for gist should be modified to include large lesions . patients with gastric gist have better survival than those with small intestinal gist as reported by emory et al . surgical management has been shown to be a critical factor in their treatment , even in the era of imatinib . achieving a negative margin resection with no spillage at the time of surgery is essential . the ability to achieve this status is paramount in choosing patients who might be candidates for a minimally invasive approach . the utility of eus has been found to be very helpful in making this determination , and , in fact , the diagnosis was made by eus in 75% of this population . it is the belief of our group that minimally invasive techniques should not be used for gastric resections that require nodal dissections ( ie , adenocarcinoma ) . the question of which surgeons are qualified to perform these minimally invasive resections is controversial . in fact , a team approach is often the best approach , because technical laparoscopic skills are required , as is excellent knowledge of upper gastrointestinal anatomy . a detailed knowledge of tumor biology and the potential role of neoadjuvant therapy are essential . it is unclear whether any surgeon could possess all of these skills , and the alignment of a team might be the best approach . there is still debate regarding the most appropriate operative approach and the extent of resection required . the aim of surgery is complete removal of the tumor with negative resection margins and preservation of anatomical function . however , even microscopically positive margins may not change overall prognosis , as demonstrated by dematteo et al . unlike adenocarcinoma , in which submucosal and subserosal lymphatic spread requires a 5 cm to 6 cm surgical margin , gastric gist tends to grow out of the primary organ instead of infiltrating the submucosal tissue . lymph node metastases are very rare , and routine lymphadenectomy is not required . wedge resection of gastric gist tumors has been widely reported to be successful . also evidence exists that laparoscopic resection of gastric gist tumors is effective with minimal morbidity , and no reported mortality . with this report , we corroborate the experience of novitsky et al who demonstrated that the laparoscopic approach appears to offer excellent therapeutic outcomes , with a 92% long - term disease - free survival for gastric gist tumors of various sizes ( 1.0 cm to 8.5 cm ) . we would like to expand the laparoscopic indications for resection of these large tumors to a size ranging from 2 . yano et al have reported the removal of 2 gastric gist tumors in the 7 cm to 8 cm diameter range by using hand - assisted laparoscopic surgery ( hals ) . if a laparoscopic approach is contemplated , several factors including patient characteristics , tumor features ( size , location , invasion ) , as well as the surgeon 's experience and expertise , need to be considered . tumor rupture during laparoscopy should be avoided , as peritoneal seeding affects the disease - free period and overall survival . resection margins need to be clear in all cases , confirming the oncological safety of the laparoscopic approach . the role of neoadjuvant and adjuvant therapy in gist has evolved over the past several years , and imatinib is now used in patients who display poor prognostic features , such as large size or mitotic activity . the main purpose of this report is to question the size limits on minimally invasive resection of gastric gist . this study has shown that large gist can be resected safely , while obeying the cancer principles that are paramount to treating this disease . gist tumors have an unpredictable behavior . even with risk stratification , careful follow - up is required . even though the majority of gist tumors are likely to recur within 2 years after surgery , follow - up beyond this period would seem sensible . although more definitive results will require a large - scale , prospective , randomized trial with longer postoperative follow - up evaluation , we conclude from this study that minimally invasive assisted approaches may be an option to treat large gastric gist tumors . obeying principles of minimal touch , no spill , obtaining a negative margin , and a safe operation with a laparoscopic approach is feasible , even in giant tumors .
objective : laparoscopic resection of large gastric gastrointestinal stromal tumors ( gist ) has been controversial . this generally has been limited to small lesions . 
 we hypothesize that laparoscopic mobilization and resection using , in some cases , extracorporeal anastomosis of the gastrointestinal ( gi ) tract is an oncologically safe alternative to open surgery even when tumors are large.methods:four patients underwent a laparoscopic approach for gastric gist tumors > 2 cm at methodist dallas medical center over a 6-month period . 
 patient demographics , operative findings , postoperative course , and pathologic characteristics were examined.results:the mean age in this patient group was 58 years ( range , 36 to 77 ) . 
 gastrointestinal bleeding and dyspepsia were the most common symptoms . 
 seventy - five percent of the patients were females . 
 mean tumor size was 10 cm ( range , 2.5 to 20 ) with distribution in the stomach as follows : 75% greater curvature and 25% antrum . 
 tumors were removed by wedge , sleeve , and partial gastrectomies . 
 two of these tumors showed a high grade and the other 2 a moderate grade of differentiation . 
 the number of mitoses was < 5/50 hpf in all the tumors . 
 no intraoperative spillage occurred in any patients , even with the largest tumor ( 20 cm ) . 
 importantly , all tumors were excised with a negative gross and microscopic margin . 
 average length of stay was 4 days . 
 no patients required reoperation , and there were no complications postoperatively.conclusion:minimally invasive assisted approaches may be an option to treat large gist tumors . obeying principles of minimal touch , no spillage , and obtaining a negative margin , 
 a safe operation with a laparoscopic approach is feasible , even in giant tumors . 
 the large size of diagnosed gist tumors should not preclude a minimally invasive approach .