Diagnostic value of CYFRA 21-1 and CEA for predicting lymph node metastasis in operable lung cancer

Tumour markers are used extensively for the management of lung cancer, including diagnosis, evaluating effectiveness of treatments, monitoring recurrence after therapy and for predicting prognosis. However, there exists a knowledge gap regarding potential quantitative correlations between tumour marker levels and the extents of lymph node involvement in primary lung cancer. The current study is comprised of 139 lung cancer patients scheduled to undergo surgical operation. Of the 139 patients, 107 were subsequently diagnosed with lung cancer without lymph node involvement and 32 were diagnosed with malignant disease with lymph node involvement by histological examination. Preoperative tumour marker levels were quantified in each patient. The median tumour marker levels were statistically higher in lung cancer patients with malignant lymph nodes than in those who suffered either benign lung disease or carcinoma in situ (Kruskal-Wallistest; P = 0.001). Tumour marker levels were significantly correlated with clinical stage (ANOVA; P = 0.009). When examined as a dichotomous variable (CYFRA 21-1 ≤ 5.0 and CEA ≤ 5.0 group and CYFRA 21-1 > 5.0 or CEA > 5.0 group), elevated tumour marker levels correlated strongly with the presence of positive lymph nodes (χ(2) test; P = 0.000). This correlation suggests that the tumour marker levels are clinical predictors for the malignant involvement of lymph nodes in operable lung cancer patients.