Colorectal gastrointestinal stromal tumors (GISTs): a retrospective study of reported cases

Although with malignant potential, there are limited information about colorectal GISTs due to their relatively low incidence among large intestine diseases and the lack of sufficient associated case reports. The aim of the study is to obtain a better understanding of colorectal GISTs and to investigate the optimal treatment for it.

Clinical data of 90 patients with colorectal GISTs published in the literature from 2003 to 2009 were analyzed with emphasis on pathology, treatment and prognosis.

The patients with tumor necrosis had a high relapse rate (p = 0.003) and a bad prognosis (p < 0.001) after surgery with negative margins (R0). Tumor necrosis had a significantly positive correlation with risk grades (p < 0.001). On the other hand, the mixed cell type had a significantly positive correlation with tumor necrosis (p = 0.016). Of the 67 cases with R0 resection, the difference of disease-free survival between the low-risk and high-risk was statistically significant (p = 0.003). Although, this was not statistically significant between the low risk and intermediate risk (p = 0.160) as well as intermediate-risk and high-risk (p = 0.229). But the high-risk had a marked relapse rate (54.8%), in comparison with the intermediate-risk (7.1%).

High-risk colorectal GISTs showed a poor outcome. A complete resection followed by routine use of tyrosine kinase inhibitors is recommended. Surgery with negative margins is the main treatment for non-high-risk group. The GISTs with tumor necrosis or mixed cell type implicate a malignant potential and a poor outcome. More attention should be paid and an extensive follow-up is warranted in this population.