Cath Lab Digest

Anaheim—Although there are a few targeted therapies available to treat patients with triple-negative breast cancer (TNBC), they are not effective. However, researchers are working on new therapies that can be used alone or in combination with chemotherapy. Several experts provided an overview of TNBC and discussed past, current, and future trends associated with the disease during a symposium at the ASHP meeting titled Understanding Triple-Negative Breast Cancer and Emerging Targeted Therapies.

Jacquelyn Lauria, RN, MS, APN-C, AOCNP, director of oncology nursing services at the Cancer Institute of New Jersey, New Brunswick, said there were 192,000 breast cancer cases and 40,000 breast cancer–related deaths in the United States in 2009. The severity and pathology depends on several factors, such as age, tumor size, axillary node involvement, lymphovascular invasion, histologic grade, hormone receptor status, and human epidermal growth factor receptor 2 (HER2)/neu amplification.

There are 5 subtypes of breast cancer: luminal A, luminal B, basal-like triple negative, HER2 positive, and unclassified. A study that Ms. Lauria discussed found that 84% of patients with luminal A breast cancer survived, with a mean survival of 7.6 years; 87% of patients with luminal B breast cancer survived, with a mean survival of 7.7 years; 75% of patients with basal-like breast cancer survived, with a mean survival of 4.9 years; and 52% of patients with HER2- or estrogen receptor (ER)-negative breast cancer survived, with a mean survival of 6.7 years.

Ms. Lauria mentioned approximately 10% to 20% of breast cancer patients have TNBC, which is characterized by earlier relapses, distinct patterns of metastases, and a lack of specific targets for treatment selection. Patients with TNBC are typically younger when diagnosed compared with other cancer patients, and the incidence is higher in African American women. She emphasized that TNBC is not one disease but rather a type of breast cancer.

Risk factors for TNBC include a BRCA1 mutation, while other factors are under investigation, such as body mass index, breastfeeding, alcohol use, and elevated waist-to-hip ratio. Ms. Lauria said that neoadjuvant studies have shown that TNBC is sensitive to chemotherapy and has a higher pathologic complete response rate than luminal breast cancers.

She also cited studies showing TNBC is associated with poorer outcomes and a higher risk of relapse than other invasive breast cancers. She said the correlation between TNBC and basal-like breast cancer is high, but they are not the same, although people frequently use the terms interchangeably: ≤10% of TNBC cases are not basal-like, while 15% to 40% of basal-like breast cancer cases are not TNBC.

Chemotherapy is currently the only effective treatment for TNBC. However, to better understand TNBC, several researchers are studying the BRCA1 pathway that plays an important role in homologous recombination. Currently, studies have indicated that BRCA1 cells are sensitive to DNA damage and develop chromosomal aberrations when exposed to DNAdamaging drugs. Ms. Lauria said that TNBC and BRCA1-deficient tumors share common characteristics. Thus, treatment options available for BRCA1-deficient cancers could possibly work well for TNBC.

Next, Chad M. Barnett, PharmD, BCOP, clinical pharmacy specialist at the University of Texas, Houston, spoke about the 2 options available to treat patients with TNBC: chemotherapy and antiangiogenic therapy. Chemotherapy is the standard, although patients with tumors ≤0.5 cm and negative lymph nodes do not require chemotherapy. Endocrine therapy and anti-HER2–directed therapy is not appropriate for patients with TNBC, according to Dr.