Diagnostic value analysis of combined detection of Trx, CYFRA21-1 and SCCA in lung cancer

The expression levels of thioredoxin (Trx), cytokeratin fragment 21–1 (CYFRA21-1) and serum squamous cell carcinoma antigen (SCCA) in patients with lung cancer and the diagnostic value of combined detection were investigated. Sixty-five patients with lung cancer in Weihai Municipal Hospital from January 2014 to June 2017 were retrospectively selected as the observation group, while 60 healthy subjects receiving physical examination were selected as the control group. The expression levels of serum Trx, CYFRA21-1 and SCCA were detected. The sensitivity and specificity of single detection and combined detection of these indexes were compared. Moreover, the diagnostic values of single detection and combined detection were analyzed using the receiver operating characteristic (ROC) curve. The levels of CYFRA21-1 and SCCA were the highest in squamous carcinoma (P<0.05). The level of Trx was the highest in small cell lung cancer compared with those in squamous carcinoma and adenocarcinoma (P<0.05). The levels of serum Trx, CYFRA21-1 and SCCA in lung cancer patients in clinical stage III–IV were obviously higher than those in patients in clinical stage I–II (P<0.001). The positive rate of Trx was the highest in small cell lung cancer, and the positive rates of CYFRA21-1 and SCCA were the highest in squamous carcinoma compared with other cancers (P<0.05). The area under the ROC curve of combined detection of the three indexes was the largest. The optimal cut-off value of combined detection of the three indexes in lung cancer was 9.952 with the sensitivity of 86.2% and specificity of 75.0%. The detection of serum Trx, CYFRA21-1 and SCCA is of great significance in the diagnosis, progression and pathological type of lung cancer, and combined detection can improve both specificity and sensitivity, which is more conducive to the positive rate of diagnosis of lung cancer.