Molecular classification and prognostication of 300 node-negative breast cancer cases: A tertiary care experience

BACKGROUND: The proportion of node-negative breast cancer patients has been increasing with improvement of diagnostic modalities and early detection. However, there is a 20–30% recurrence in node-negative breast cancers. Determining who should receive adjuvant therapy is challenging, as the majority are cured by surgery alone. Hence, it requires further stratification using additional prognostic and predictive factors. SUBJECTS AND METHODS: Ours is a single institution retrospective study, on 300 node-negative breast cancer cases, who underwent primary surgery over a period of 7 years (2005–2011). We excluded all cases who took NACT. Prognostic factors of age, size, lymphovascular emboli, estrogen receptor (ER), progesterone receptor (PR), HER2neu Ki-67, grade and molecular classification were analyzed with respect to those with and without early events (recurrence, metastases or second malignancy, death) using-Pearson Chi-square method and logistic regression method for statistical analysis. RESULTS: Majority belonged to the age group of 50–70 years. On univariate analysis, size >5 cm (P = 0.03) and ER negativity had significant association (P = 0.05) for early failures; PR negativity and lymphovascular emboli (LVE) had borderline significance (P = 0.07). Multivariate analysis showed size >5 cm to be significant (P = 0.04) and LVE positivity showed borderline significant association (P = 0.07) with early failures. About 62% belonged to luminal category followed by basal-like (25%) in molecular classification. CONCLUSIONS: ER negativity, PR negativity, LVE/lymphovascular invasion positivity and size >5 cm (T3 and T4) are associated with poor prognosis in node-negative breast cancers.