With the recent improvements in the risk grading criteria, and the in-depth clinical study of imatinib, the diagnosis and treatment of GISTs has dramatically improved. The risk criteria proposed by the NIH are widely used worldwide and was shown to have a reliable correlation with patient survival after GIST surgery[8, 19]. Imatinib is one of the few tumour-targeting drugs with significant clinical efficacy that has been incorporated into the standard postoperative treatment regimen for patients with high-risk GIST. Preoperatively, imatinib can shrink the tumour to promote the complete surgical resection and reduce the occurrence of surgical complications, especially for local high-risk GIST[20]. A precise classification of the risk grade can have a significant impact on surgery and prognosis. However, the classification criteria rely on pathological results, so it is important to accurately predict and classify the risk grade before surgery.
PLR, WLR, MLR, and NLR are biomarkers of the immune response, and have been shown to be prognostic factors for many types of tumours. East et al.[17] found that the NLR and WLR were independent predictors of postoperative overall survival in colorectal cancer. For GIST, Racz et al.[15] showed that a high PLR is related to a poor prognosis in GIST patients. Goh et al.[16] found that a high PLR and high NLR are independent risk factors for postoperative progression-free survival in GIST patients. Cananzi et al.[18] found that a high MLR was negatively correlated with disease-free survival after GIST surgery. Peripheral blood cell detection is a convenient and routinely performed preoperative test, but only a few studies have explored the predictive value of inflammatory biomarkers for GIST risk grading.
In the present study, we evaluated the value of inflammatory markers such as PLR, WLR, MLR, and NLR in the risk grading of GISTs, compared the differences in their predictive value between different GIST risk groups, and evaluated their diagnostic significance. We found that the PLR, WLR, MLR, and NLR had no obvious diagnostic significance in the very low-risk group, but showed good predictive power in the low- and medium-risk groups. In contrast, the diagnostic significance in the high-risk group was the most prominent. At present, many studies have assessed the prognostic significance of the NLR and PLR for GISTs. A high NLR and PLR are often associated with poor prognosis, which is consistent with our results. The cut-off values of NLR and PLR (2.059 and 131.8) showed a good predictive power in the high-risk group. Few studies have assessed the prognostic significance of the WLR in GISTs. Therefore, we first evaluated the predictive significance of the WLR for grading the risk of GISTs, and found that this had a higher predictive value compared with the NLR and PLR. The MLR has been reported as a prognostic factor in studies involving colorectal cancer, multiple myeloma, Hodgkin's lymphoma, and other types of tumours, and has also been confirmed as an independent prognostic factor for disease-free survival after GIST surgery in the study by Cananzi[18]. In this study, the MLR showed a better predictive value in the intermediate-risk and low-risk groups, and also exhibited the most valuable predictive value compared with other inflammatory markers in the high-risk group.
This study has some limitations. Firstly, this was a retrospective study. Although promising results were obtained, there are still few studies on the MLR and WLR for GIST, and further prospective studies are needed to verify these results. Secondly, there are numerous grading criteria for GIST, and we only evaluated the widely used NIH standards, so the practicability of this study was limited.
In summary, this study assessed a large sample of 843 patients and found that preoperative PLR, WLR, MLR, and NLR values were all good predictors for the risk of GIST; however, there were significant differences in the predictive value among different risk groups. In the very low-risk group, the predictive value of all four markers was deficient, but these markers showed better predictive value in the low-risk and intermediate-risk groups. However, these four markers had the best predictive value in the high-risk group, among which, the MLR was the most evident. Clinically, the peripheral blood test is a cheap and convenient method that can help determine the risk grade of GIST before surgery, and can provide a reliable basis for the selection of targeted preoperative imatinib therapy and postoperative survival evaluation.