To observe the therapeutic effect of arsenious acid combined with Tα-1 thymus peptide and megestrol acetate on advanced non-small cell lung cancer. Nintey-two patients were divided randomly into the treated group (n = 45) and the control group (n = 47). The treated group were treated with arsenious acid combined with Tα-1 thymus peptide and megestrol acetate

and the control group were treated with chemotherapy in the NP protocol. (1) Therapeutic effect : In the 36 patients of the treated group

2 were evaluated as CR

8 as PR

9 as MR

8 as SD and 9 as PD

the CR+PR rate being 27. 7% (10/36)

while in the 40 patients of the control group

the corresponding numbers were 3

10

11

9

7 and 32. 5% (13/40). Comparison between the CR + PR rate between the two groups showed insignificant difference (P>0. 05) . (2) Clinical benefit rate: The positive rate of Karnofsky scores in the treated group and the control group was 44. 4% and 20.0% respectively; and the positive rate of body weight in the two groups was 33. 3% and 12. 5% respectively

the difference between the two groups was significant ( allP<0. 05) . (3) Changes of T- cell subsets and NK cell activity: CD4 and CD4/CD8 ratio after treatment in the treated group increased significantly (P<0. 05)

while in the control group

CD3

CD4

CD4/CD8 ratio and NK cell activity all lowered significantly (P<0.01) . Comparison between the two groups after treatment showed significant difference in CD4

CD4/CD8 ratio and NK cell activity

with those in the treated group all higher than those in the control group (P<0.01) . (4) Adeverse-reaction; No serious adverse reaction was found in both two groups. (5) Median survival period:The treated group was 30 weeks and that in the control group was 28. 5 weeks

and the difference between the two groups was insignificant (P>0. 05). Arsenious acid combined with Tα-1 thymus peptide and megestrol acetate was a relatively effective scheme with low toxicity in treating advanced NSCLC.