[en] Objective: Study on the change of serum soluble Fas (sFas) level and prognostic relation for non-small cell lung cancer (NSCLC) patients with concurrent radio-chemotherapy using enzyme linked immunosorbent assays(ELISA). Methods: Sixty patients were obtained. The sFas level were compared before treatment with one month after treatment, and healthy donors were used as controls level of sFas. The sFas level of before treatment were compared treatment efficiency patients (complete remission and partial remission, 50 patients) and treatment inefficiency patients (no change and progressive disease, 10 patients). The correlation was analyzed between 2-year survival NSCLC patients and their sFas level. Results: The sFas level before treatment in NSCLC patients was obviously higher than healthy controls (8.55 ± 0.63) ng/L and (6.03 ± 0.55) ng/L; (t=18.63, P<0.01), with 1 month after treatment obviously lower than before treatment in NSCLC patients (7.24 ± 0.52) ng/L and (8.55 ± 0.63) ng/L; (t=12.44, P<0.01). The sFas level of before treatment was treatment efficiency patients obviously lower than treatment ineffectived patients (8.02 ± 0.43) ng/ L and (8.97 ± 0.42) ng/L; (t=8.67, P<0.01), with 2-year survival patients obviously(26 patients)lower than shortage 2-year survival patients (34 patients) (t=645.88, P<0.05). Conclusions: Concurrent radio- chemotherapy can reduce sFas level in NSCLC patients, the changes of sFas level before and after treatment may provide worth prognostic for NSCLC patients. (authors)