Previously, GISTs were the most common submucosal tumors with potential malignancy in the upper gastrointestinal (GI) tract, no matter if their size is small or large, and it was difficult to predict their properties. Therefore, surgical excision is indicated if a histopathological diagnosis of GIST is made (GIST 2008). But the handling for 2 cm or less gastric GISTs does not have consensus in Japan. In the actual clinical site, the 2 cm or less gastric GISTs were resected in accordance with Japanese GIST Therapeutic Guidelines.
On the other hand, Suzuki et al (2010) reported that two of 16 cases in 2 cm or less GISTs increased during followed-up and recommended that it should be followed-up carefully. Also Nishida (2009) recommended a followed-up for 2 cm or less GISTs without ulceration and border irregularity. The recent rapid advances in endoscopic intervention therapy provide a potential method for en bloc resection of small Gastric SMTs. The modality of endoscopic treatment includes endoscopic band ligation (Liu-Ye et al. 2012; Sun et al. 2007), endpscopic submucosal dissection (ESD) (Lee et al. 2006; Filippo et al. 2012). The main defect of band ligation is that sloughed specimens are not available for pathological confirmation. Nevertheless, benign condition is comprised in SMTs like leopmyoma and heterotopicc pancreas, the problem is that perforation occurred during the ESD. Furthermore, successful complete resection of ESD is not 100%. In 2010, Bai et al (2010) reported that submucosal dissection technology for small GISTs < 2 cm in stomach is feasible with a 28% perforation rate, obviously higher than an overall 4% perforation in ESD for early gastric cancer. Also, full-thickness resection was reported treatment of SMTs. Zhou et al (2011) reported the complete resection rate was 100% in 26 patients with a SMT and there was no bleeding, peritonitis, and abdominal abscess. However, such procedures described previously cannot be accepted for a very benign condition in Japan.
We compared the two divided groups of GISTs with 2 cm or less and GISTs with >2 cm. The mean age was significantly higher in Group I than in Group II (p < 0.05). Therefore, GISTs were anticipated that the size increased as time passes. In tumor site, there was no GISTs >2 cm on the L site. Then, the GISTs on the M and U site were considered to have a chance of increasing. The histopathological and immunostaining findings from the surgically resected specimens were in agreement with those from the mucosal cutting biopsy specimens in all cases in Group I. In addition, all cases were in agreement because of the mitotic count. Therefore histological risk grade were also in agreement in all cases of Group I. These results indicate that a follow-up of 2 cm or less GISTs on the L site can also be considered acceptable. On the other hand, single case was not in agreement with the mitotic count between the mucosal cutting biopsy specimens and the surgically resected specimens in Group II. En bloc resection was very important for accurate histopathlogical diagnosis and histological risk grade of GIST. So traditionally, we consider that the gastric GISTs >2 cm and 2 cm or less gastric GISTs located on the M,U site were candidate for surgical treatment.
In conclusion, if 2 cm or less gastric SMTs located on the L site with a diagnosis of histpathlogical very low risk GIST, we consider that a follow-up of them can also be considered acceptable. On the other hand, traditionally, we consider that the gastric GISTs >2 cm and 2 cm or less gastric GISTs located on the M,U site were candidate for surgical treatment. This study demonstrated that the clinicopathological characteristic and clinical handling of the patients with 2 cm or less small gastric GISTs.