Serum squamous cell carcinoma antigen in the monitoring of radiotherapy treatment response in carcinoma of the cervix.

In this study, squamous cell carcinoma antigen (SCC) was detected in 96 of 157 patients with squamous cell carcinoma of the cervix and the percentage of patients with raised SCC levels increased with the stage of disease (P less than 0.01). The use of serial SCC assays and cervical biopsy histology during the course of radiotherapy to predict tumor response to irradiation was assessed. In patients who were given external irradiation before intracavitary radium, a high SCC level or the presence of viable tumor cells in the biopsy was found to be of no predictive value. However, at completion of radiotherapy, i.e., after intracavitary radium application, patients with persistently high SCC levels had a significantly higher incidence of residual tumor than patients whose SCC levels returned to normal (P less than 0.01). In 60% of patients with a persistently high SCC level, viable tumor was found in the cervical biopsy at the end of radiotherapy. On the other hand, only 5.4% of patients whose SCC level returned to normal had residual tumor.