Effective head and neck tumor markers. The continuing quest

To evaluate the clinical value of two serologic tumor markers, squamous cell carcinoma-associated antigen and plasma lipid-bound sialic acid, for identifying cancers of the head and neck, plasma specimens were obtained from patients receiving care for untreated newly diagnosed cancers of the head and neck, routine surveillance for recurrence, or treatment for chronic nonmalignant otolaryngologic conditions. Using identical methods at two institutions, levels of both markers were determined blind to diagnoses for patients with biopsy-proven cancers of the head and neck (n = 134) and for those defined as cancer free based on clinical evaluation for 6 months (n = 140). Disease status was determined blind to tumor marker level results. Cancer prevalence was 48.9%. Applying standard normal limits used alone, plasma lipid-bound sialic acid test sensitivity was 63.4% and specificity was 77.9%. For squamous cell carcinoma-associated antigen alone, test sensitivity was 27.6% and specificity was 85.0%. Neither test alone appears sensitive enough to effectively detect early cancers of the head and neck. When the results of both tests in series combination were positive, sensitivity was 18.7% and specificity was 95.0%. If either was positive in parallel combination, sensitivity was 72.4% and specificity was 68.0%. Further evaluation is required that applies different definitions of normal and determines longitudinal changes with disease status.