Prognostic Impact of Triple Negative Phenotype in Conservatively Treated Breast Cancer

Abstract

To evaluate overall survival (OS), disease-free survival (DFS), and local-recurrence free survival (LRFS) rates in a subgroup of patients affected by breast cancer expressing a particular phenotype (estrogen receptor negative, progesterone receptor negative, and Human Epidermal Growth Factor receptor 2 negative) known as "triple negative" (TN). Data of 387 women affected by early breast cancer who underwent whole-breast radiotherapy after conservative surgery with or without chemotherapy and/or hormone therapy between January 2002 and December 2008, in the Department of Radiotherapy at Regional Cancer Center, were retrospectively evaluated. Chi-squared test was used to compare prognostic factors (age, histology, tumor size, nodal status, grading, and adjuvant therapy) between TN patients and non-TN patients. OS, DFS, and LRFS rates were analyzed using Kaplan--Meier proportional log-rank test; impact of prognostic factors on poor outcome was evaluated using Cox regression stepwise method on univariate and multivariate analysis. Mean follow-up time was 57.6 months (range13.7-109.7). TN patients were more likely to have ≥T2 tumors (p = 0.0003), grade 3 tumors (p = 0.0001) and to receive chemotherapy as adjuvant therapy (p =< 0.0001). TN patients had lower 5-years-OS (p = 0.039) and lower 5-years-DFS (p = 0.003) compared with non-TN patients. No difference in 5-years LRFS was found (p = 0.49). After multivariate analysis, TN status was found to be a predictive factor for OS (p = 0.004) and for DFS (p = 0.01), but not for LRFS (p = 0.8). TN patients have lower survival when compared with non-TN patients, but similar LRFS rates. These patients can be treated in a conservative surgical protocol, but should receive more aggressive and tailored adjuvant therapies.