Cancer of the uterine cervix: sensitivity and specificity of serum squamous cell carcinoma antigen determinations.

Between 1978 and 1989, 451 patients with cervical squamous cell carcinoma were referred to our department, of whom 143 experienced persistent or recurrent disease. Serial serum samples of the patients were analyzed for the presence of squamous cell carcinoma antigen (SCC). The incidence of elevated pretreatment serum SCC levels ranged from 37% in stage IB (N = 173) to 90% in stage IV (N = 19). Multivariate analysis showed that deep stromal infiltration and lymph node metastases were associated with significantly higher serum SCC levels. Serum SCC trends correlated with the course of disease: after treatment the sensitivity (percentage positive results in patients with persistent disease) was 79% and the specificity (percentage negative results in patients with no evidence of disease) was 91%. During follow-up, the sensitivity of the assay was 85.5% in patients with recurrent disease. However, the positive predictive value of a single serum SCC value greater than 2.5 ng/ml for tumor recurrence was only 49%. This figure rose to 76% when two consecutive elevations were determined. Stage and pretreatment serum SCC level were the only factors found to influence survival, using Cox's regression analysis with five pretreatment variables.