Locoregional recurrence in patients with triple-negative breast cancer: preliminary results of a single institution study.

PURPOSE: To examine the impact of radiotherapy on breast cancer patients with triple-negative (ER-, PR-, HER2/neu-) disease.
MATERIALS AND METHODS: A prospectively collected database of 152 triple negative breast cancer patients was initiated in 2004. A total of 77 patients who had all phases of their therapy (surgery, chemotherapy, and radiotherapy) at our institution with a minimum of 2-months follow-up are included. Patients with all types of surgery (lumpectomy or mastectomy), chemotherapy (neoadjuvant or adjuvant), and radiotherapy (tangents only or comprehensive nodal irradiation) are included. Patients received radiotherapy in the setting of breast-conservation and in the postmastectomy setting for ≥5 cm primary tumors and/or ≥4 positive lymph nodes. Patients were divided into 2 groups for statistical analysis, based on whether they received radiotherapy or not.
RESULTS: In the cohort, 53 (69%) received radiotherapy, 24 (31%) received no radiotherapy. The median follow-up was 23.2 months (range, 2.0-63.1). In the alive patients, the median follow-up time was 25.6 (range, 2.0-63.1) months. Patients who received radiotherapy were significantly more likely to be of a higher AJCC stage (P < 0.001) than patients who did not receive radiotherapy. Of the patients who received radiotherapy, 33 (61.1%) did so for breast conservation. For the entire group, 1- and 3-year overall survivals are 90.9% and 86.3%, respectively. The 3-year actuarial locoregional relapse-free survival probability for patients who received radiation was higher than those who did not receive radiation (79.6% vs. 57.9%, P = 0.049).
CONCLUSIONS: Despite significantly lower AJCC stage, patients with triple-negative breast cancer who do not undergo radiotherapy have a significantly higher risk of locoregional recurrence.