肺癌高发区化学预防研究

Chemoprevention in the high incidence area of lung cancer

Since 1984, mass screening for cancer has been carried out in the realgar and tin mines, high incidence areas of lung cancer. Certain epidemical characteristics were found in precancerous lesion of lung cancer. Chemopreventive treatment were carried out by giving R1 [N-(p-ethoxycarbophenyl) retinamide] & R2 [N-(p-carboxyphenyl) retinamide]-retinoids synthesized by the Institute of Materia Medica, Chinese Academy of Medical Sciences. A prospective randomized double-blind control trial on the subjects with moderate or severe atypical hyperplasia cells in the sputum was conducted. Thirty-seven patients were treated by R1 (50 mg/d, p. o; total dose: 18.25 g/yr/case). In view of the absorption of R2 being better than R1, R2 (20 mg/d, p. o; total dose: 3.6/g/6mos/case) was given to 52 patients instead of R1. Patients in the control group were treated by riboflavin (50 mg/d, p. o.). The results showed that general status of the patients was improved. IgA and IgM in the serum were increased and the arsenic skin lesions were relieved after the treatment with R1 and R2. As compared with the control group, the incidence of lung cancer was 1:4 and mean degree of hyperplasia in the sputum dropped. It is suggested that these drugs are safe and effective in the chemoprevention of lung cancer. It is worth for further study.