Elevated plasma CEA during radiotherapy for glottic carcinoma of the larynx

Carcinoembryonic antigen (CEA) levels in plasma were determined serially during radiotherapy in 10 patients with glottic carcinoma of the larynx. There were moderate high levels initially in three patients, all of clinical stage T1. Elevation during irradiation was noted in seven patients at a tumor dose of around 4000 rad. At this does the tumors were no longer visible and it is possible that the raised CEA represents circulating breakdown products from them. As raised levels were not seen in all patients, it is less likely that irradiation of laryngeal tissue by itself raises CEA plasma levels. After treatment, CEA normalized to the initial levels.