Endoscopic resection of gastric gastrointestinal stromal tumors (GISTs) that are less than 2 cm in diameter and have more than 5 mitoses per 50 high power fields leads to a low risk of recurrence and long-term metastasis, according to a new study published in Surgical Endoscopy

The authors of the study concluded that the endoscopic resection of small gastric GISTs with high histological grades is safe and feasible.

To date, there are limited data on small GISTs with high histological grades. To gain more insight into this type of GIST, a team of researchers from China led by Ping-Hong Zhou conducted a nested cohort study of 55 patients diagnosed with GIST between January 2008 and July 2019. The team analyzed the clinicopathological and perioperative characteristics of the tumors at baseline as well as the risk of recurrence and metastasis during follow-up.


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They reported that the tumor size ranged from 0.8 to 2 cm with a median of 1.7 cm. Of the 55 patients, 33 (60%) underwent endoscopic submucosal dissection while the remaining 22 (40%) underwent endoscopic full-thickness resection.

The mean number of mitotic figures was 8.9 per 50 high power fields. There was only 1 severe adverse event in the form of bleeding after surgery. 

The follow-up period ranged from 13 to 133 months with a median of 53 months.

In this period, 5 patients (9.1%) underwent additional therapies, including gastrectomy and adjuvant imatinib. Recurrence occurred in 2 patients (3.6%). No patient showed any sign of metastasis.

The authors stated that they did not observe any significant differences between GISTs with less than 10 mutations per 50 high power fields and those with 10 or more mutations per 50 high power fields in terms of baseline clinical characteristics and recurrence. “The natural course of small gastric GISTs with high mitosis counts needs further studies,” they added.

Reference

Chen TY, Xu JX, Chen WF, et al. Long-term prognosis of small gastric gastrointestinal stromal tumors with high histological grade: a longitudinal nested cohort study. Surg Endosc. Published online February 8, 2022. doi:10.1007/s00464-021-08725-2