Optimal adjuvant chemotherapy in breast cancer: selection of agents

Abstract

Historically, the selection of the most effective adjuvant regimen for breast cancer patients was based on tumor size and nodal status but this approach took into account the stage only, without considering that the biology of the tumor matters as well, as breast cancer is a heterogeneous disease at the molecular level. In the present manuscript we will attempt to address the issue of selecting the most appropriate cytotoxic agents for adjuvant programs in the clinically and biologically distinct subgroups of endocrine responsive (luminal A and luminal B), HER2 positive and triple negative breast cancer patients.

Keywords::

• breast cancer
• chemotherapy
• chemotherapy
• predictive factor
• subtype

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Adjuvant systemic therapy has improved survival of patients with breast cancer.

• Clinical and laboratory evidences strongly support the concept that breast cancer is a heterogeneous disease in terms of clinical behavior and tumor biology.

• The selection of the most appropriate cytotoxic agents for adjuvant programs in distinct subgroups of endocrine responsive (luminal A and luminal B), HER2 positive and triple-negative breast cancer patients is a issue of great interest.

• The majority of luminal A tumors have an excellent prognosis with endocrine therapy alone, and the use of chemotherapy is much debated especially in disease with large tumor burden.

• Luminal B tumors are characterized by poorer outcomes and increased risk of relapse; chemotherapy in addition to endocrine treatment is indicated for the majority of these patients.

• Anti-HER2 adjuvant therapy with trastuzumab combined with chemotherapy is the standard for patients with HER2-positive disease.

• Chemotherapy with standard cytotoxic agents is the only systemic treatment option for triple-negative breast cancers.

• Multiple parameters can influence the response to chemotherapy, but none have been endorsed into clinical use because of their inability to predict response to treatment.