Prognosis of synchronous bilateral breast cancer.

ABSTRACT

BACKGROUND: The prognosis of patients with synchronous bilateral breast cancer (SBBC) is usually based on the tumour with the worst pathological features. There is little evidence in the literature for this assumption, potentially impairing reasoned decisions on optimal adjuvant therapy. METHODS: This was a case-control study in which 68 women with SBBC were matched with 128 women with unilateral breast cancer. Both the GuysRisk prognostic model and the Nottingham Prognostic Index were used to determine the bilateral tumour with the poorer prognosis. Controls were matched for age, menopausal status, date of diagnosis, histological type and grade, and oestrogen receptor and axillary node status. RESULTS: Both prognostic models indicated the same side tumour with the worst prognosis. Kaplan-Meier survival curves for both disease-free and overall survival showed no significant difference in outcome between the two groups. CONCLUSION: Prognosis was determined by the tumour with the worst prognosis, with no additional worsening of outcome incurred from the second tumour.