Sequential antitumour immunoreactivity and carcinoembryonic antigen levels as a guide to prognosis in colorectal carcinoma.

Twenty-five patients with colorectal carcinoma were tested for blood-lymphocyte anti-tumour cytotoxicity and carcinoembryonic antigen (CEA) levels at three-monthly intervals for eighteen months or more after resection, and examined clinically every three to six months. Twelve of the patients were followed for two years and one for four years. The six patients whose tumours recurred showed positive blood lymphocyte antitumour cytotoxicity and elevated plasma CEA levels at some time from six months after operation, usually well before the recurrence was clinically detectable.