NLR, PLR improve early detection of second primary cancer after gastric cancer

Combining the neutrophil-to-lymphocyte (NLR) and platelet-to-lymphocyte (PLR) ratios with existing diagnostic methods helps improve early detection of second primary cancers (SPC) after initial gastric cancer (GC), a recent study has found.

Seventy-eight patients who developed SPCs after GC participated in the present study and were compared against 99 patients with single GC and 107 healthy controls. The retrospective analysis used receiver operating characteristic (ROC) curves to assess the diagnostic value of NLR, PLR, carcinoembryonic antigen (CEA), and carbohydrate antigen 19-9 (CA19-9), alone or in combination, for SPCs.

Patients with SPC after GC showed significantly higher NLR than their single GC counterparts at each cancer stage (p<0.01), while the increase in PLR was significant only in stages II–IV (p<0.001). CEA and CA19-9 levels were elevated in SPC vs single GC patients at cancer stage IV (p<0.05).

Diagnostic analysis revealed that at an optimal cut-off of 3.31, NLR showed an AUC of 0.845 (95 percent confidence interval [CI], 0.781–0.909), with sensitivity and specificity of 82.1 percent and 81.8 percent, respectively. Meanwhile, at a cut-off of 177.01, PLR had an AUC of 0.796 (95 percent CI, 0.730–0.863). Corresponding sensitivity and specificity were 88.5 percent and 65.7 percent.

Both NLR and PLR individually had better AUC, sensitivity, and specificity values compared with CEA and CA19-9.

Notably, pairwise combinations among the indicators showed superior diagnostic performance, with the combination of NLR and PLR showing the highest AUC (0.881, 95 percent CI, 0.829–0.934). Sensitivity and specificity values were 79.5 percent and 85.9 percent, respectively.