Luminal (Her2 negative) prognostic index and survival of breast cancer patients

Purpose: The group of luminal (Her2 negative) is distinguished from other subtypes of breast cancer. We aimed to produce a prognostic index specific for luminal (Her2 negative) subtype breast cancer that could assist clinical treatment. Methods: The test set comprised 406 consecutive luminal (Her2 negative) breast cancer patients. The relationship of 11 clinicopathologic factors including survivin with the 5-year disease-free survival was analyzed. Results: In univariate analysis, TNM stage, surgery, tumor size, lymph node involvement, and survivin expression were prognostic factors. In multivariate analysis, tumor size [HR (95% CI): 1.98 (1.12-3.49), p = 0.019], the number of lymph node metastasis [HR (95% CI): 1.75 (1.33-2.29), p < 0.0001] and the expression of progesterone receptor [HR (95% CI): 0.58 (0.36-0.95), p = 0.029] can independently predict prognosis. Prognostic index (PI) was calculated as 0.68 × tumor size + 0.56 × the number of lymph node metastasis - 0.54 × PR. According to the PI, patients were categorized into three groups: low, middle, and high risk group with the 5-year disease-free survival rates of 91.91%, 84.97% and 70.47%, respectively (P < 0.001). In the validation set, the luminal prognostic index (LPI) remained significant. Conclusion: The LPI may be a useful tool for evaluating the outcome of patients with luminal (Her-2 negative) breast cancer.