(ChemotherapyAdvisor) – Relapsed breast cancer following lumpectomy and reexcision may be related to residual tumor burden, according to a team of US-based researchers. This conclusion is based on a study entitled “Triple negative breast cancer is associated with an increased risk of residual invasive carcinoma after lumpectomy,” which will be published in an upcoming issue of Cancer

In this study, the investigators aimed to determine the factors that lead to the development of residual carcinoma following lumpectomy in patients with triple negative (TN) breast cancer. To meet this aim, an analysis was performed to assess the risk of treatment failure as well to determine the pathologic factors that correlate with this risk.

Pathologic specimens were collected from women with invasive breast cancer who had been previously treated with lumpectomy followed by reexcision. These specimens were analyzed for several pathologic characteristics including tumor size, grade, and nodal stage; status of estrogen receptor, progesterone receptor, and human endothelial growth factor receptor 2 (Her2); lymphovascular invasion; post-reexcision findings; and more.

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The characteristics recorded for the patient population (N=369) included median age, 57 years; median tumor size, 1.5 cm; positive margins, 36%; positive lymph nodes, 32%; Her2-positive, 4.5%; and 12.5% TN. “Overall, 32% of patients had invasive cancer in their reexcision specimens, and 51% of those with the TN subtype had residual invasive disease on reexcision compared with 30% to 31% 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).

The investigators suggested that the increased risk of local treatment failure in TN patients may be related to increased residual tumor burden.