Outcome of pN0 Triple-Negative Breast Cancer with or without Lymph Node Irradiation: A Single Institution Experience

Abstract

The optimal management of patients with pathologically node-negative triple-negative breast cancer (pN0 TNBC) remains unclear. We hypothesized that lymph node irradiation (LNI; internal mammary chain/periclavicular irradiation) had an impact on outcomes of pN0 TNBC. A cohort of 126 consecutive patients with pN0 TNBC treated between 2007 and 2010 at a single institute were included. All radiotherapy (breast/chest wall, ±LNI) was delivered adjuvantly, following completion of surgery ± chemotherapy. Tumors were reviewed and histologic features were described. Tissue microarrays were constructed and tumors were assessed by immunohistochemistry using antibodies against ER, PR, HER2, Ki-67, cytokeratins 5/6, 14, epidermal growth factor receptor and androgen receptor. Patients were divided into two groups for statistical analysis: LNI (LNI+) or no LNI (LNI-). We focused on disease-free survival (DFS), metastasis-free survival (MFS), and overall survival (OS). Fifty-seven and 69 patients received or not LNI, respectively. Median age was 52 (range [25-76]) and 55 (range [29-79]) in LNI+ and LNI- group (p = 0.23). LNI was associated with larger tumors (p = 0.033), central/internal tumors (33 versus 4, p < 0.01) and more chemotherapy (86% versus 59.4% p < 0.01). The median follow-up was 53.5 months. The rate of first regional relapse (associated or not with distant relapse) was low in both groups. There was no difference in 4-year DFS (82.2% versus 89.9%; p = 0.266), MFS (87.0% versus 91.1%; p = 0.286) and OS (85.8% versus 89.9%; p = 0.322) between LNI+ and LNI- group, respectively. In univariate analysis, only clinical size (T >10 mm versus ≤10 mm), histologic size (pT >10 mm versus ≤10 mm) and grade 3 (versus grade 2) were found to be significantly associated with shorter DFS. Omission of LNI in patients with pN0 TNBC does not seem to result in poorer outcome. Further studies are needed to specifically evaluate LNI in pN0 TNBC with histologic grade 3 and/or (p)T >10 mm.

Triple-negative breast cancer in Peru: 2000 patients and 15 years of experience

“…Previous experiences used different definitions for both OS and EFS. While some authors defined it as the time from diagnosis until the event (death or recurrence) [12,13,26,40], others start the follow-up from the treatment date (medical or surgery) [10,29,41]. This latter approach prevents incurring an immortal time bias in the survival analysis by avoiding the observation time of patients without therapy.…”

Radiotherapy after surgery has significant survival benefits for patients with triple‐negative breast cancer

“…A recent study reported that women with T1‐2N0 TNBC treated with modified radical mastectomy without radiotherapy had a significantly increased risk of locoregional recurrence and poorer survival . On the other hand, another study revealed that omission of radiotherapy in patients with pN0 TNBC did not seem to result in poorer outcome . Those previous reports investigating the survival outcomes of TNBC patients according to local radiotherapy status have produced conflicting results.…”

Effectiveness of hypofractionated and normofractionated radiotherapy in a triple‐negative breast cancer model

“…Radiotherapy (RT) is an important component in the treatment of breast cancer, especially as an adjuvant approach in breast conserving therapy. Postoperative irradiation is also getting continuously important in the management of the TNBC subtype, although the benefit is still debatable, concerning overall survival ( 10 , 11 ). Recent studies revealed no differences in dose fractionation adding an evidence to support the use of moderate hypofractionated whole-breast irradiation in TNBC patients ( 23 , 24 ).…”

“…Radiotherapy for breast cancer can reduce the risk of a local relapse and decrease the risk of cancer-associated mortality in the patient and is therefore a crucial part of therapeutic options for the patient ( 7 – 9 ). While the benefit of radiotherapy concerning overall survival for patients with TNBC is still debatable ( 10 , 11 ), adjuvant radiotherapy is an indispensable part of breast conserving therapy assuring locoregional control. Thus, estimating the role of radiotherapy and the modalities of postoperative irradiation in the TNBC prognosis is continuously important.…”