Squamous cell carcinoma antigen: clinical utility in squamous cell carcinoma of the uterine cervix.

This study further defines the clinical utility of squamous cell carcinoma antigen (SCC-Ag) in initial squamous carcinoma of the cervix, response to treatment, and in the detection of recurrence. Serum specimens were drawn and analyzed from patients with squamous cell carcinoma. Charts were reviewed on 272 patients with 1053 samples evaluated. Treatment of patients prior to the availability of the assay and patients lost to follow-up resulted in lower total numbers of initial and recurrent values. Data were analyzed to detect trends during and after treatment. All values at or above the lowest detectable level of antigen were included; that is, 1.5 ng/ml and above. A SCC-Ag value > or = 2.0 ng/ml drawn at any time during the disease process has a 96.3% positive predictive value, while a value < 2.0 ng/ml is 97.2% specific for absence of disease. Fifty-three percent of 103 patients had elevated SCC-Ag levels prior to treatment, with the proportion increasing accordingly with advancing stage at diagnosis. In 70 patients with recurrence, 81% had elevated values. Squamous cell carcinoma antigen predicted recurrence an average of 6.9 months prior to detection of clinically evident disease. Patients with initially negative SCC-Ag levels may demonstrate elevated values with tumor recurrence. This marker accurately reflects the response to treatment in patients who have elevated levels prior to treatment. Squamous cell carcinoma antigen is a useful tumor marker in the management of patients with squamous cell carcinoma of the uterine cervix.