Triple-negative breast cancer (TNBC) is distinct from other breast cancers, because the tumor cells lack estrogen and progesterone receptors (hormone receptors) and are also negative for human epidermal growth factor receptor 2 (HER2).
Relapsed breast cancer following lumpectomy and re-excision may be related to residual tumor burden, according to a team of US-based researchers in their study entitled "Triple negative breast cancer is associated with an increased risk of residual invasive carcinoma after lumpectomy," which has been published in the newest issue of Cancer.
In this study, the investigators wished to determine the factors that lead to the development of residual carcinoma following lumpectomy in patients with triple negative breast cancer (TNBC). Pathologic specimens were collected from women with invasive breast cancer who had been previously treated with lumpectomy followed by re-excision. These specimens were analyzed for several pathologic characteristics, including tumor size, grade, and nodal stage, status of estrogen receptor, progesterone receptor, human endothelial growth factor receptor 2 (Her2), and lymphovascular invasion.
The characteristics recorded for the patient population (N=369) included:
- median age, 57 years
- median tumor size, 1.5 cm
- positive margins, 36 percent
- positive lymph nodes, 32 percent
- Her 2-positive, 4.5 percent
- triple negative, 12.5 percent
"Overall, 32 percent of patients had invasive cancer in their re-excision specimens, and 51 percent of those with the TN subtype had residual invasive disease on re-excision compared with 30 percent to 31 percent for other subtypes," the investigators reported.
Age, tumor size, margin status, lymphovascular invasion, nodal status, and TN subtype were associated with elevated risk of residual invasive cancer. TN subtype maintained significance, with an odds ratio of 3.28 (P=.002).
Triple receptor-negative cancer is most commonly an irregular, noncalcified mass with ill-defined or spiculated margins on mammography and a hypoechoic or complex mass with an irregular shape and noncircumscribed margins on ultrasound. Most triple receptor-negative cancers are discovered on physical examination, and when compared with non-triple receptor-negative cancers, triple receptor-negative cancers were found in younger women and were a higher pathologic grade. TNBC had more aggressive pathologic characteristics and is associated with poorer survival in patients with stage I breast cancer.
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The investigators suggested that the increased risk of local treatment failure in TNBC patients may be related to increased residual tumor burden. More intensive adjuvant chemotherapy or a different therapeutic strategy targeting this population is necessary. Clinical trials with various targeted approaches alone or in combination with different chemotherapeutic agents are currently underway.
Has anyone noted similarities in their patient populations? What protocols, if any, have been established in your practices for TNBC?
- Sioshansi S, Ehdaivand S, Cramer C, Lomme MM, Price LL, Wazer DE. Triple negative breast cancer is associated with an increased risk of residual invasive carcinoma after lumpectomy,Ē Cancer. 2012 Aug 15;118(16):3893-8.
- Kim JE, Ahn HJ, Ahn JH, Yoon J Breast Cancer. 2012 Jun;15(2):197-202. Impact of triple-negative breast cancer phenotype on prognosis in patients with stage I breast cancer.
- Krizmanich-Conniff KM, Paramagul C, Patterson SK, Helvie MA, Roubidoux MA, Myles JD, Jiang K, Sabel M. Triple receptor-negative breast cancer: imaging and clinical characteristics. AJR Am J Roentgenol. 2012 Aug;199(2):458-64.
- Bilici A, Arslan C, Altundag K.Promising therapeutic options in triple-negative breast cancer. BUON. 2012 Apr-Jun;17(2):209-22.