[Cutaneous delayed hypersensitivity to costus root oil in lung cancer].

Costus root oil is a new primary sensitizer for examining the delayed, cell-mediated immune system. Ninety-nine patients with lung cancer were tested for skin reactions to costus root oil. The incidence of positive reactions to costus root oil decreased with the progress of lung cancer. The percentage of lung cancer patients who survived was significantly greater for positive than for negative patients. This study shows that skin reactions to costus root oil are related the tumor growth and prognosis in lung cancer.