Cell proliferation and apoptosis in stage III inoperable non-small cell lung carcinoma treated by radiotherapy

Purpose: The purpose of this study was to assess the prognostic value of th e expression of p53 and bcl-2, the apoptotic index and the expression of to poisomerase II alpha in patients with inoperable non-small cell lung cancer (NSCLC) treated with high dose radiotherapy. Patients and methods: A number of 161 patients with inoperable NSCLC treate d with high dose radiotherapy (60 Gy) were included. Immunohistochemical an alysis was used to assess the expression of nuclear p53-protein, topoisomer ase II alpha and cytoplasmatic expression of bcl-2, while spontaneous apopt osis was assessed using in situ labeling. The minimal follow up period was 2 years. Results: Local control did not only depend on the presence of p53 expressio n, but also on the proportion of p53 positive cells. The most important pro gnostic factor was the apoptotic index. A high apoptotic index was associat ed with worse local control, more distant metastases and a significantly wo rse overall survival. No association was noted between the expression of bc l-2 and topoisomerase II alpha with any of the endpoints. Conclusion: This study indicates that p53 expression and the apoptotic inde x are prognostic factors with regard to local control in patients with inop erable NSCLC treated with radiotherapy and by combining these 2 factors, a clinically relevant estimation of the local control probability can be made . The apoptotic index turned out to be the only factor significantly relate d to survival. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.