Prospect of Immunotherapy in Neoadjuvant/Adjuvant Treatment for Early Breast Cancer

Minoru Miyashita; Takanori Ishida

Disclosures

Chin Clin Oncol. 2020;9(3):28 

In This Article

Abstract and Introduction

Abstract

Immunotherapy is revolutionary and changing the cancer therapy of multiple solid tumors. Immunotherapy began with discovering the proteins of immune checkpoints such as programmed death-1 (PD-1), programmed death ligand-1 (PD-L1) and cytotoxic T-lymphocyte associated antigen-4 (CTLA-4). Breast cancer, unlike cancers with high tumor mutation burden, is generally considered to be of intermediate immunogenicity; therefore, the efficacy of checkpoint monotherapy is limited. Among breast cancer subtypes, triple negative breast cancer (TNBC) is considered to be the most immunogenic and is mainly evaluated in clinical trials. Some trials have demonstrated that checkpoint inhibitors when combined with chemotherapy improve the survival of TNBC patients. When investigating new drugs, a neoadjuvant setting is preferred because drug efficacy can be evaluated earlier using pathological complete response (pCR) as an alternative endpoint for survival. The strategy is based on the accumulated results that pCR after neoadjuvant therapy significantly correlates with both progression free survival (PFS) and overall survival (OS). We aimed to review relevant articles, and discuss the current position of immunotherapy and future prospects of immunotherapy as neoadjuvant/adjuvant therapy in breast cancer based on our conclusions from the findings in the current literature.

Introduction

Breast cancer is the most common cancer diagnosed in women and has become one of the main global public health problems. In the recent decade, breast cancer is treated using a multidisciplinary approach that includes surgery, chemotherapy, endocrine therapy, molecular targeted therapy and radiotherapy, which have been beneficial to reduce breast cancer mortality.[1] However, numerous unresolved issues surrounding breast cancer still remain. Recently, development of immunotherapies that successfully inhibited immune-check point proteins resulted in a durable effect in some cancers such as malignant melanoma, non-small cell lung cancer, and urothelial cancer. In the other side, breast cancer is generally thought to be a low immunogenic tumor because of the low mutation burden compared with that in the so-called hot immunogenic tumors.[2] Nevertheless, immunotherapy is expected to be used as a new treatment modality especially for triple negative breast cancer (TNBC), which has a higher immunogenicity among subtypes of breast cancer. Here, we review the articles and discuss the current position of immunotherapy and future prospects of immunotherapy as neoadjuvant/adjuvant therapy in breast cancer based on our conclusions from the findings in the current literature.

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