Pure mucinous carcinomas of the breast: prognostic study including DNA flow cytometry.

ABSTRACT

BACKGROUND: Prognostic factors for pure mucinous carcinomas of the breast are controversial; data on DNA ploidy and S-phase fraction (SPF) are lacking. We examined the relation of these parameters with histological features and patient survival. METHODS: DNA flow cytometry was performed on 69 fresh or frozen pure mucinous carcinomas samples. Results were interpreted according to patient survival. RESULTS: Tumor size exceeded 2 cm in 40.5% of cases. Lymph nodes were involved in 11.5% of cases and never when tumor size was less than 2 cm. Aneuploidy was only observed in one-quarter of the tumors. Very few tumors had a high-SPF or a high histological grade (7.2% of all cases). These two parameters were of prognostic value respectively for disease-free (P=0.035) and overall survival (0.050). Patients with tumors>2 cm had shorter overall survival than patients with tumors≤2 cm (P=0.028). Disease-free and overall survivals were not influenced by nodal status and hormone receptors (HRs) status. Patients with aneuploid tumors had shorter disease-free survival than patients with diploid tumors (P=0.031). The combination of tumor size and DNA ploidy was strongly predictive of survival (P<10(-3)) six patients with large aneuploid tumors had a poor outcome (1-year overall survival 16.7%). CONCLUSION: We identified a subset of patients with a poor prognosis, namely those with large aneuploid tumors. This study confirms the good prognosis of pure mucinous carcinomas, particularly when tumor is less than 2 cm (corresponding to cases without lymph nodes involvement), thus challenging the need for axillary nodal examination.