Abstract
To evaluate the utility of CEA and CA19-9 as indicators of the effects of preoperative irradiation for rectal cancer, we studied the relationship between tissue localization or serum level of these antigens and the grade of irradiation effect. Thirty-two out of 63 patients were treated by surgery alone, and the other 31 cases were given preoperative irradiation. In tissue CEA staining, almost all cancer glands showed focal or diffuse cytoplastic staining in each group except one case. In tissue CA19-9 staining, there were 16 positive cases in the non-irradiated group and 15 in the irradiated group. There were only two diffuse cytoplasmic staining cases in the non-irradiated group and 8 in the irradiated group. In those patients having no liver metastasis, the reduction ratio of the serum CEA value after irradiation was 46.5±14.1% in the nonresponding patients, while it was 60.3±19.2% in the responding patients. In patients with liver metastasis, the serum CEA level increased 14.5% on average, and the serum CA19-9 level increased as well, when compared with the level in the preirradiation stage independent of the irradiation effects. In conclusion, tissue immunoreactivity is maintained after irradiation and determination of serum CEA and CA19-9 levels before and after irradiation is thought to be useful for estimating the effect of irradiation.
