Prognostic value of p53 for local failure in mastectomy-treated breast cancer patients

The loss of p53 function is a recognized adverse prognostic factor in invasive breast cancer. Several studies have shown a relationship between the nuclear accumulation of p53 protein (a surrogate marker of p53 inactivation) and poor disease-free and overall survival. In general, however, these studies did not report the prognostic value of p53 for local failure, which we have therefore assessed retrospectively here.

Accumulation of p53 protein was evaluated by immunohistochemistry in 1,530 mastectomy-treated breast cancer patients (259 radiation therapy [RT]- and 1,271 mastectomy only [No RT]-treated patients). Statistical comparisons were made between p53 protein accumulation, estrogen/progesterone receptors, nodal status, tumor size, and local failure rate (LFR). Local failure was defined as tumor recurrence involving the chest wall and/or the ipsilateral supraclavicular/axillary lymph nodes. The median follow-up period was 62 months.

In the No RT group, the LFR was 9.1% and 16. 5% in p53-negative and p53-positive patients, respectively (P<.001). Multivariate analysis revealed that p53 protein accumulation was significantly associated with an increased risk of local relapse (relative risk [RR], 1.7; 95% confidence interval [CI], 1.2 to 2.4). Nodal status and tumor size were also significant factors. In the RT group, the LFR was 9.3% and 21.5% in p53-negative and p53-positive patients, respectively (P = .009). Multivariate analysis revealed that p53 protein accumulation was significantly associated with an increased risk of local relapse (RR, 2.5; 95% CI, 1.1 to 5.7), as was nodal status.

Nuclear accumulation of p53 protein is independently associated with a significantly increased local failure rate in breast cancer patients treated with mastectomy, with or without radiation.