Is pleural amylase predictive for thoracic cancer?

We have assessed the predictive value of amylase in pleural effusions for lung cancer by searching the English-language literature through Medicine (1966-1988) and the bibliographic sections of review articles. Three published series of patients were identified. Of these, we selected two prospective studies from which the specificity and sensitivity of pleural amylase for lung cancer could be calculated. Elevated amylase was found in 12 of 100 cases of lung cancer, in three (6%) of 52 cases of pulmonary infections, and in five of six cases of pancreatitis or pancreatic cysts. The sensitivity of amylase levels for lung cancer was therefore 12%, its specificity 93%. We conclude that the predictive value of pleural amylase for lung cancer is clinically insignificant, and such measurements are not warranted unless pancreatitis or oesophageal rupture is suspected.