Value of squamous cell carcinoma antigen levels in invasive cervical carcinoma.

Squamous cell carcinoma (SCC) antigen (Ag) levels were measured by radioimmunoassay in 64 patients with invasive squamous cell cervical carcinoma and 9 patients with nonsquamous carcinoma before the initiation of treatment. The mean antigen level in the squamous group was 10.5 ng/ml compared with 1.3 ng/ml in the nonsquamous group. In the patients with squamous cell carcinoma, mean SCC Ag level correlated well with stage, except for bulky stage IB tumors (P less than 0.05), where mean level was much higher than expected. Patients with exophytic tumors had significantly higher SCC Ag levels than those with nonexophytic tumors. Follow-up on 62 evaluable patients ranged from 20 to 40 months. The mean pretreatment SCC Ag level for patients free of disease at last contact was 5.6 ng/ml, in contrast to 16.1 ng/ml for those with recurrent disease. Only 32% of patients free of disease had pretreatment levels of 4.0 ng/ml or greater, while 86% of those with recurrent disease had such values (P less than 0.05). Forty patients had follow-up samples drawn 1 to 14 months after treatment. Mean post-treatment SCC Ag levels dropped to 1.8 ng/ml in 21 patients free of disease (73% decrease), but remained elevated at 13.4 ng/ml (17% decrease) in 19 patients with recurrences. The specificity of follow-up SCC Ag levels as a predictive test for outcome was 90%, with a sensitivity of 63%. We conclude that pretreatment SCC Ag levels correlate well with tumor stage, lesion morphology, and extent of disease. SCC antigen levels may be used to follow patients to determine effectiveness of treatment.