Predictive value of bcl-2 immunoreactivity in prostate cancer patients treated with radiotherapy

Background and purpose: Recent experimental evidence suggests that overexpr ession of bcl-2, a protein functioning by blocking apoptosis, may influence the treatment outcome in human tumours, including prostate cancer. To test the clinical implications of this hypothesis, rumours from patients with p rostate cancer treated with external beam radiotherapy were investigated fo r bcl-2 immunoreactivity (IR) and correlated with prognosis and treatment o utcome. Materials and methods: Bcl-2 IR was evaluated in archival tumour specimens obtained through transurethral resection from 42 patients with localized pr ostate cancer (T0-T4, NO and MO). Bcl-2 IR expression was related to stage, grade and cancer-specific survival. Specimens were obtained prior to admin istrating routine radiotherapy for all patients. Results: Bcl-2 IR was present in 19/42 (45%) tumours. The bcl-2-positive pa tients had a significantly longer cancer-specific survival than the bcl-2-n egative patients (10.3 Versus 3.4 years, P < 0.04). At follow-up (7-19 year s), nine patients were still alive, 26 patients had died of prostate cancer and seven patients had died of other causes. Conclusions: This study indicates that pre-treatment bcl-2 overexpression i s related to a favourable outcome in prostate cancer treated with radiother apy. Low bcl-2 along with a high stage may be a predictor of poor prognosis and these patients might benefit from additional treatment. (C) 1998 Elsev ier Science Ireland Ltd. All rights reserved.