p53 status: an indicator for the effect of preoperative radiotherapy of rectal cancer

Abstract

Background: Rectal carcinoma is a common malignancy, with a history of high local recurrence rates following surgery. In recent years. preoperative radiotherapy and refined surgical technique have improved local control rates.

Aim: To investigate the relationship between expression of nuclear p53 protein and the outcome in rectal carcinoma, with and without short-term preoperative radiotherapy.

Material: Specimens from 163 patients from the Southeast Swedish Health Care region included in the Swedish rectal cancer trial between 1987-1990.

Method: New sections from the paraffin blocks of the preoperative biopsy and the surgical specimen were examined immunohistochemically using a p53 antibody (PAb 1801).

Result: Expression of nuclear p53 protein was seen in 41% of the tumours. The p53 negative patients treated with preoperative radiotherapy had a significant reduction of local failure compared with the non-irradiated p53 negative patients (P = 0.0008). In contrast, p53 positive patients showed no benefit from preoperative radiotherapy. The interaction between p53 status and the benefit of radiotherapy was statistically significant (P = 0.018).

Conclusion: Expression of nuclear p53 protein in rectal carcinoma seems to be a significant predictive factor for local treatment failure after preoperative radiotherapy. Further investigations are necessary to select patients for preoperative treatment based on analysis of the preoperative biopsies.