Impact Of Breast Cancer Subtypes Research Articles

Breast Cancer Subtype and Distant Recurrence after Ipsilateral Breast Tumor Recurrence

There is little information about the impact of breast cancer subtype on prognosis after ipsilateral breast tumor recurrence (IBTR). One hundred eighty-five patients were classified according to breast cancer subtype, as approximated by estrogen receptor, human epidermal growth factor receptor 2 (HER2), and Ki-67, of IBTR, and we evaluated whether breast cancer subtype was associated with distant recurrence after IBTR. There was a significant difference in distant disease-free survival (DDFS) after IBTR according to breast cancer subtype defined by a cutoff of the Ki-67 index of 20% (p=0.0074, log-rank test). The 5-year DDFS rates for patients with luminal A, luminal B, triple-negative, and HER2 types were 86.3, 57.1, 56.6, and 65.9%, respectively. In addition, breast cancer subtype was significantly associated with distant recurrence after IBTR on adjustment for various clinicopathologic factors (p=0.0027, Cox proportional hazards model). Our study suggests that breast cancer subtype based on immunohistochemical staining predicts the outcomes of patients with IBTR. Further analyses are needed (UMIN-CTR number UMIN000008136).

Abstract P6-07-32: Prognosis of metastatic breast cancer subtypes: the hormone receptor/HER2 positive subtype is associated with the most favorable outcome

Abstract Background: In early breast cancer the different subtypes and their prognostic relevance are well known, contrary to the knowledge on prognostic relevance of subtypes in metastatic breast cancer. This study presents survival estimates after diagnosis of distant metastases of breast cancer subtypes in a recent cohort in which the treatment is representative of current clinical practice. Patients and methods: All patients diagnosed with metastatic breast cancer in one of eight participating hospitals in the South-East part of the Netherlands between 2007–2009 were included and all medical charts were reviewed. Patients were categorized in 4 subtypes based on the hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status of the primary tumor; HR positive/HER2 negative, HR positive/HER2 positive, HR negative/HER2 positive and triple negative (TN). Metastatic survival was estimated using the Kaplan-Meier product-limit method. Cox proportional hazards model was used to determine the prognostic impact of breast cancer subtype, adjusted for possible confounders. Results: A total of 815 patients were included; the HR+/HER2− subtype comprising 66%, the HR−/HER2+ subtype 8%, the TN subtype 15% and the HR+/HER2+ subtype 11% of patients. The four subtypes were associated with different metastatic survival times; the HR+/HER2+ subtype was associated with the best metastatic survival (median, 32.9 months), compared to 22.1 months for the HR+/HER2− subtype, 19.5 months for the HR−/HER2+ subtype and 7.7 months for the TN subtype. Aside from subtype, other prognostic factors of metastatic survival were site of metastases and metastatic-free interval. Conclusion: Of the four subtypes, the HR+/HER2+ subtype was associated with the most favorable outcome, in terms of metastatic survival. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-07-32.

Impact of Breast Cancer Subtypes and Treatment on Survival: An Analysis Spanning Two Decades

We investigated the impact of breast cancer molecular subtypes and treatment on survival in a cohort of medically insured women followed for more than 20 years. We examined 934 female members of an integrated health care delivery system newly diagnosed with invasive breast cancer between 1988 and 1995 and followed them through 2008. Tumors were classified into four molecular subtypes on the basis of their expression profile: luminal A; luminal B; basal-like; and HER2-enriched. We followed women from the surgery date to death, health plan disenrollment, or study's end. HR and 95% confidence intervals (CI) were fit using Cox proportional hazards models adjusting for cancer treatments and tumor characteristics. A total of 223 (23.9%) women died because of breast cancer during the 21-year study period. Compared with women with luminal A tumors, women with HER2-enriched (HR 2.56, 95% CI 1.53-4.29) and luminal B tumors (HR 1.96, 95% CI: 1.08-3.54) had roughly a two-fold increased adjusted risk of breast cancer mortality. In addition, the survival curves suggest that risk of late mortality persists in women with luminal A tumors. Among women with health care coverage, molecular subtypes were important predictors of breast cancer mortality. Women with HER2-enriched tumors and luminal B subtypes had the poorest survival despite adjusting for important covariates. In a cohort followed for more than 20 years, women with HER2-enriched tumors had worse survival, but interestingly, the survival curve for women with luminal A tumors continued to steadily decline after 10 years of follow-up.

Impact of Breast Cancer Subtypes on Local-Regional Outcomes

The identification of genomic subtypes of breast cancer nearly 10 years ago provided powerful insight into the genetic heterogeneity of the disease. In the decade since, the concept of tumor biology has been shown to be highly relevant for determining survival outcomes and response to therapy, as well as in explaining variations in the disease noted clinically among women of different ages and races. Establishing tumor subtypes has also driven efforts to identify underlying pathways that drive the biologic phenotype and that can potentially be targeted therapeutically. However, far less is known about the impact of biologic subtypes on local regional outcomes and whether the same subtype specific biologic properties identified in the setting of distant disease can be translated to the local-regional context. In this review, we summarize current research in this area.