Relationships between squamous cell carcinoma antigen and cytokeratin 19 fragment values and renal function in oral cancer patients

Squamous cell carcinoma antigen (SCC-Ag) and cytokeratin 19 fragment (CYFRA) are used to screen and monitor oral cancer patients. However, recent studies have reported that tumour markers become elevated as renal function decreases, regardless of tumour progression. A retrospective study was performed of 423 oral cancer patients who underwent blood testing for these tumour markers and other blood analytes during a 10-year period. The values of SCC-Ag and CYFRA increased significantly with decreasing renal function (P < 0.01), and the values were abnormal at a median 2.6 ng/ml for SCC-Ag and 4.7 ng/ml for CYFRA in the group with estimated glomerular filtration rate (eGFR) values of < 30 ml/min/1.73 m2. The factors that were related to the variation in tumour markers were albumin and creatinine. The cut-off values of eGFR were 59.7 ml/min/1.73 m2 for SCC-Ag and 63.6 ml/min/ 1.73 m2 for CYFRA, and the cut-off age when the tumour markers might rise due to the effect of renal function were 72 years for SCC-Ag and 73 years for CYFRA. In conclusion, decreased renal function should be taken into account when evaluating tumour markers in oral cancer. In addition, tumour markers are likely to be overestimated in patients over the age of 72-73 years.