p53 and c-erbB-2 but not bcl-2 are predictive of metastasis-free survival in breast cancer patients receiving post-mastectomy adjuvant radiotherapy in Taiwan

Background: Patients with breast cancer often receive radiotherapy after mastectomy if they are at a high risk of local recurrence, but the prognosis varies among patients. We conducted a study to evaluate p53, bcl-2 and c-erbB-2 as predictors of prognosis in breast cancer patients receiving post-mastectomy radiotherapy, which has not been well defined in the Taiwanese population. Methods: We recruited 74 consecutive patients with primary operable breast cancer who were treated with mastectomy followed by locoregional radiotherapy and studied the presence of p53, bcl-2 and c-erbB-2 expressions in tumor tissues by immunohistochemical staining. Associations between the protein expressions and clinical outcomes, including local recurrence-free survival (LRFS), metastasis-free survival (MFS) and overall survival (OS), were evaluated. Results: The median follow-up time was 55 months. Expressions of p53, bcl-2 and c-erbB-2 were observed in 14 (19%), 28 (38%) and 39 (53%) patients, respectively. Both p53 and c-erbB-2 were significant predictors of MFS. The 5-year MFS for p53-negative and p53-positive tumors were 61.2 and 35.7% (P = 0.01) and 5-year MFS for c-erbB-2-negative and c-erbB-2-positive tumors were 71.3 and 42.4% (P = 0.01). Whereas expression of bcl-2 protein is associated with favorable clinicopathological features, it was not related to LRFS, MFS or OS. Multivariate analyses confirmed c-erbB-2 and p53 expressions as predictors of MFS independent of tumor size, histological grading and lymph node involvement. Conclusion: Expressions of p53 and c-erbB-2 are independent predictors of MFS in this Taiwanese population. Further research should be conducted on their application in the treatment and follow-up of patients.