**4. Peripheral blood monocytes in gastric cancer assessment**

score consisted of NLR (cut-off 1.59), PLR (cut-off 155.67), T/depth of invasion, macroscopic

As previously outlined, lymph node status is crucial to select the most appropriate treatment in early gastric cancer. PLR has been analysed in this context. In a retrospective assessment of 312 early gastric cancer cases subjected to surgical treatment, high PLR along with high NLR was significantly associated with lymph node metastases. Although both PLR and NLR showed this association by univariate analysis, only PLR was identified as an independent risk factor by multivariate analysis. Thus PLR, but not NLR was included in a complex score. The scoring system was based on the identified independent risk factors: PLR (cut-off 106, based on ROC analysis), age, tumour size, grade and depth of invasion and successfully vali-

In patients diagnosed with resectable gastric cancer, high PLR correlated with higher stage [16]. The association between high PLR and higher stage was confirmed in a multicentre study of 245 gastric cancer patients [61]. When a meta-analysis of 8 studies was performed comprising data on 4513 patients with gastric cancer, elevated PLR showed association with advanced cancer stage (III–IV). The relevant odds ratios was 1.99 (95% CI 1.60–2.46) as

Generally, PLR can accurately reflect tumour burden. In the study carried out by Cetinkunar et al., the 228 cases were classified as early vs. advanced and non-metastatic vs. metastatic ones. PLR could discriminate the groups in both models. The mean PLR values were 160.3 in early and 231.6 in advanced gastric cancer; 192.7 in non-metastatic and 251.0 in metastatic cases [88].

The diagnostic role of PLR has been explored as well. Thus, the mean values of PLR were significantly higher in gastric cancer patients than in healthy controls [16, 18]. The parameter

Several meta-analyses of PLR have been devoted to PLR in gastric cancer, yielding partially conflicting results. In a meta-analysis of 8 studies comprising 4513 cases of gastric carcinoma, elevated PLR correlated with lymph node metastasis, deeper invasion (T3–T4) and advanced cancer stage (III–IV) but it was not predictor of overall survival. The relevant odds ratios were 1.50 (95% CI = 1.24–1.82) for N+, 2.01 (95% CI = 1.49–2.73) for T3–T4 and 1.99

Fourteen cohorts and 6280 cases were re-evaluated within the frames of another meta-analysis. Authors found out that PLR was associated with poor overall survival but not with cancer-free survival. High PLR predicted poor survival in Caucasians, patients receiving

might seem promising as it is not affected by smoking in contrast to NLR [81].

type according to Bormann and tumour size [55].

dated in a prospective training set [72].

*3.2.3. TNM stage*

170 Gastric Cancer

reported by Xu et al. [85].

**3.3. The diagnostic role of PLR**

**3.4. Meta-analyses of PLR in gastric cancer**

(95% CI = 1.60–2.46) for stage III–IV [85].

Although macrophages are a significant component of tumour microenvironment, quite few studies have been devoted to the prognostic role of monocytes in relation with other cells in peripheral blood of gastric cancer patients.

However, in a recent large study enrolling 3243 gastric cancer patients, high monocyte to white cell ratio (MWR) was identified as an independent prognostic factor of poor survival. In the same study, high NLR, high PLR, high monocyte to lymphocyte ratio, high neutrophil to white cell ratio, low lymphocyte to white cell ratio (LWR) were associated with survival in univariate analysis, but only low LWR and high MWR were independent prognostic factors for poor survival [90].

In gastric cancer patients who have undergone gastrectomy, decreased lymphocyte to monocyte ratio (LMR) was significantly associated with worse overall survival, cancer-specific survival and cancer-free survival. The cut-off was estimated by ROC analysis and was 4.95. However, as a prognostic factor for overall survival, cancer-specific survival and cancer-free survival, LMR was not superior to NLR [47].
