EFFECT OF SUBCLINICAL LEAD-INTOXICATION ON LARYNGEAL-CANCER

In this study we investigated the possible relationship of laryngeal c ancer and subclinical lead intoxication, using the depression of amino levulinic acid dehydratase (ALAD) activity in blood as indicator. Twen ty-six patients with laryngeal cancer and 53 normal controls met the c riteria to enter the study. Blood ALAD activity values in the patients with laryngeal cancer ranged from 27.1 to 75.3 U/I with a mean of 50. 79 U/I. The respective values in the control group ranged from 36.2 to 98 U/I with a mean of 59.76 U/I. There was a statistically significan t difference between the two means (0.001<p<0.01), whereas blood lead concentrations in all patients were within normal limits. These findin gs support the hypothesis that low level lead intoxication (subclinica l blood lead levels), from cars, industries and products, may contribu te to the risk of laryngeal cancer. Further investigation is needed to clarify the exact relationship between lead and cancer of the larynx.