Outcomes of patients with inflammatory breast cancer by hormone receptor- and HER2-defined molecular subtypes: A population-based study from the SEER program

Abstract

BackgroundThe aim of this study was to evaluate the outcomes of patients with inflammatory breast cancer (IBC), with emphasis on the role of molecular subtypes and radiotherapy.MethodsA retrospective cohort study to investigate overall survival (OS) and breast cancer-specific mortality (BCSM) in patients with IBC was conducted using data obtained by the Surveillance, Epidemiology, and End Results (SEER) program from 2010–2013. Cox multivariate regression was used to calculate the adjusted Hazard Ratios (aHR).Results403 patients were eligible for this study. Patients in the group with hormone receptors (HR)+/HER2- subtype had an OS of 79.6% compared with 89.0 % in the group with (HR)+/HER2+ subtype and 76.8% in the HR-/HER2+ group and 62.9% in the triple-negative (TN) group. BCSM was 16.3% for the HR+/HER2- group, 9.8% for the HR+/HER2+ group, 21.7% for the HR-/HER2+ group, and 30.5% for the TN group. For distant metastases, the results showed that there was a high probability of bone metastasis in HR-positive groups, brain and liver metastasis in HER2-positive groups, and lung metastasis in the TN group. Multivariate analysis demonstrated that estrogen receptor and HER2 positivity were associated with better survival and that the TN subtype had a poorer OS and BCSM compared with other subtypes (P<0.05). Furthermore, patients who received radiotherapy were more likely to have improved survival (P< 0.05).ConclusionInflammatory breast cancer appears to alter the prognosis in association with the receptor status and molecular subtypes. Radiotherapy was still considered to be a crucial treatment for patients with IBC.

Pathologic Complete Response (pCR) and Survival of Women with Inflammatory Breast Cancer (IBC): An Analysis Based on Biologic Subtypes and Demographic Characteristics

“…Our results differ from a recent analysis of patients with IBC in the SEER database, which reported the best survival outcome for HR + /HER2 + . [20] Approximately 20% of patients in the SEER analysis had HR + /HER2 + tumors compared with 36% in our study. This may be explained by different inclusion criteria and disease definition in the latter study.…”

“…To aid in decision-making, IBC is increasingly being classified into biologic subtypes based on their phenotypic expression of HR and HER2 receptors. [20,21] While phenotypic subtypes are important for predicting outcomes among women with non-IBC stage groups, this is not well established for IBC.…”

Development of CNS metastases and survival in patients with inflammatory breast cancer

“…It is our belief that the underlying, unfavorable biology of IBC overcomes the contribution of molecular breast cancer subtype, a finding our group has reported previously. 4,22 Furthermore, if we consider CNS metastasis a negative prognostic feature, this observation seems to go against data recently published by Li et al, 23 who showed that breast cancer molecular subtype did, in fact, strongly influence OS and breast cancer-specific mortality. It should be noted, however, that the patient population used in that study came from SEER data from 2010-2013, which was a much different era of therapy, especially for HER21 disease.…”

Does nonmetastatic inflammatory breast cancer have a worse prognosis than other nonmetastatic T4 cancers?

“…Inflammatory breast cancer (IFLBC) is rare and constitutes 1% to 5% of all breast cancers. [1][2][3] Both patients with IFLBC and patients with noninflammatory T4 breast cancer (non-IFLBC) have a heavy disease burden in the breast; however, IFLBC is characterized clinically by a rapid onset of symptoms, including skin edema and erythema encompassing at least one-third of the breast, and pathologically by the presence of tumor emboli in the dermal and parenchymal lymphatic vessels of the breast. 1,4 Although the presence of tumor emboli in the dermal lymphatics is a hallmark of IFLBC, it is histologically identified in fewer than 75% of patients and is, therefore, not a requirement for diagnosis.…”