“…As for lung cancer, the use of serial serum CEA determinations in the monitoring of patients with surgicallytreated non-small cell lung cancer revealed a sensitivity of 58% in the detection of recurrence; this figure increased to 88% with concomitant analysis of serum CA 125 and squamous cell carcinoma antigen (218). Serial CEA assay may also be useful in a number of other tumors that have been less well studied to date (89,117,137,138,185,172,184,187,188,195,(219)(220)(221)(222)(223)(224)(225)(226)(227)(228)(229). In patients with gastric or esophageal carcinoma, for example, an elevated CEA level during serial follow-up after preoperative chemotherapy has been shown to be predictive of relapse, and has demonstrated the potential for diagnosis of recurrent disease in advance of its clinical presentation (140).…”