Relationship between intrinsic subtypes and tumor responses to neoadjuvant chemotherapy in patients with locally advanced breast cancer

Article type: Research Article

Authors: Ooe, Asako^{a; *} | Takahara, Sachiko^b | Sumiyoshi, Kazuhiro^a | Yamamoto, Hitoshi^a | Kawai, Jun^c | Shiba, Eiichi^a

Affiliations: [a] Osaka Breast Clinic, Osaka, Japan | [b] Department of Breast Surgery, Kitano Hospital, Osaka, Japan | [c] Department of Pathology, Kansai Denryoku Hospital, Osaka, Japan

Correspondence: [*] Corresponding author: Asako Ooe, Osaka Breast Clinic, 1-3-4 Fukushima, Fukushima-ku, Osaka 553-0003, Japan. Tel.: +81 6 6450 4108; Fax: +81 6 6454 0041; E-mail: obc@osaka-breast-clinic.com

Abstract: Background:For locally advanced breast cancer, neoadjuvant chemotherapy (NAC) is the standard of care for downstaging the tumor prior to surgery, and improved prognoses that are associated with pathological complete responses (pCR) have been noted, particularly in patients with human epidermal growth factor receptor 2 (HER2)-positive and triple negative (TN) tumors. Objective:The aim of this study was to assess the differences in pathological responses among intrinsic subtypes of local lesions and status of axillary lymph nodes (Ax LN). Methods:A consecutive series of 134 patients with locally advanced breast cancer who were treated with NAC was analyzed. Tumors were classified into the following 5 subtypes according to immunohistochemical staining results: Luminal A type, Luminal B type (HER2-negative and HER2-positive), HER2 type, and TN type. Results:In Luminal A, Luminal B (HER2-negative), Luminal B (HER2-positive), HER2, and TN tumors, the pCR rates were 10% (4 of 40), 19% (8 of 42), 42% (8 of 19), 59% (10 of 17), and 38% (6 of 16), respectively. HER2-positive tumors showed good therapeutic effects, while Luminal A tumors showed less therapeutic effects. Conclusions:Strategies that are determined according to intrinsic subtypes are becoming very important in the treatment of locally advanced breast cancer.

Keywords: Intrinsic subtypes of breast cancer, neoadjuvant chemotherapy, therapeutic response

DOI: 10.3233/BD-130345

Journal: Breast Disease, vol. 34, no. 1, pp. 9-17, 2013