Apoptosis and bcl-2 expression as predictors of survival in radiation-treated non-small-cell lung cancer

Objectives: We assessed the role of apoptosis and the expression of bcl-2, p53, and c-myc oncoproteins in pretreatment histologic specimens as a predi ctor of response to radiation therapy and survival in non-small-cell lung c ancer (NSCLC) patients. Methods: Pretreatment biopsy specimens of 68 patients with NSCLC (62 squamo us cell carcinoma, 6 adenocarcinoma) were stained with hematoxylin and eosi n, From 5 high-powered fields, the apoptotic index (AI) was calculated as t he ratio of apoptotic tumor cells to the total number of tumor cells. Bcl-2 , p53, and c-myc oncoprotein expression was detected by immunohistochemical staining. Results: Twenty-nine cases showed partial or complete remission, whereas 39 showed no response. AI ranged from 0.2 to 12.0% (mean +/- SD; 4.3 +/- 2.6% , median 4.0%), There was no difference in AI between responders (4.0 +/- 2 .3) and nonresponders (4.5 +/- 2.8, p > 0.05). However, in the responders, AI was correlated with the degree of change in tumor volume (r = 0.41, p < 0.05). In an analysis of 53 subjects who survived more than I month after t he completion of radiation therapy, the patients with a higher AI (n = 27, MST = 22.8 m) survived longer than those with a fewer AI (n = 26, MST = 9.2 , log-rank, p = 0.03). Patients expressing bcl-2 had poorer survival (n = 2 2, MST = 6.0 m) than patients without bcl-2 (n = 31, 22.8 m,p < 0.003). Acc ording to multivariate analysis, three variables, bcl-2 expression, AI, and response to radiation, were independent prognostic factors for survival. Conclusion: A low level of spontaneous apoptosis and expression of apoptosi s blocking bcl-2 protein in pretreatment histology predict a poor prognosis for radiation-treated NSCLC patients. (C) 2001 Elsevier Science Inc.