Cohort Study of Secondary Endocrine Therapy in Metastatic Breast Cancer with a Poor Response to Initial Endocrine Therapy
|Naruto Taira1*, Tomomi Fujisawa2, Kazuhiro Araki3, Takayuki Iwamoto1, Kentaro Sakamaki4, Masato Takahashi5, Tomohiko Aihara6 and Hirofumi Mukai7|
|1Department of Breast and Endocrine Surgery, Okayama University Hospital, 2-5-1 Shikatacho, Okayama Kita-ku, Okayama, 700-8558, Japan|
|2Department of Breast Oncology, Gunma Prefectural Cancer Center, 617-1 Takahayashinishicho, Ota, Gunma, 373-8550, Japan|
|3Department of Breast Medical Oncology, The Cancer Institute Hospital, Japanese Foundation for Cancer Research, 3-8-1 Ariake, Koto-ku, Tokyo 135-8550, Japan|
|4Department of Biostatistics and Epidemiology, Yokohama City University Graduate School of Medicine, 4-57 Urafune, Minami-ku, Yokohama, Kanagawa, 232-0024, Japan|
|5Department of Breast Surgery, National Hospital Organization Hokkaido Cancer Center, 2-3-54 Kikusui 4-jo, Shiroishi-ku Sapporo-shi Hokkaido, 003-0804, Japan|
|6Breast Center, Aihara Hospital, 3-4-30, Makiochi, Minoh, Osaka, 562-0004, Japan|
|7Division of Breast and Medical Oncology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan|
|*Corresponding Author :||Naruto Taira
Department of Breast and Endocrine Surgery
Okayama University Hospital, 2-5-1 Shikatacho
Okayama Kita-ku, Okayama, 700-8558 Japan
E-mail: [email protected]
|Received date: March 04, 2016; Accepted date: April 08, 2016; Published date: April 15, 2016|
|Citation: Taira N, Fujisawa T, Araki K, Iwamoto T, Sakamaki K, et al. (2016) Cohort Study of Secondary Endocrine Therapy in Metastatic Breast Cancer with a Poor Response to Initial Endocrine Therapy. J Clin Trials 6:260. doi:10.4172/2167-0870.1000260|
|Copyright: © 2016 Taira N, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.|
Background: Several classification models of sensitivity and resistance to endocrine therapies have been proposed for the clinical course of initial endocrine therapy for metastatic breast cancer. However, the efficacy and safety of secondary endocrine therapy in cases with a poor response to the initial endocrine therapy have not been examined.
Methods: A multicenter prospective observational study is planned with the objectives of demonstrating the efficacy and safety of secondary endocrine therapy in estrogen receptor (ER)-positive, human epidermal growth factor receptor type2 (HER2)-negative postmenopausal metastatic breast cancer for which initial endocrine therapy did not have a favorable clinical effect (i.e., low sensitivity to initial endocrine therapy). The subjects are patients with breast cancer with low sensitivity to initial endocrine therapy, and are defined as cases with recurrence during 5 years of adjuvant therapy or those with metastatic breast cancer that showed progression within 9 months after initial endocrine therapy. The efficacy and safety of current endocrine therapeutic agents selected by physicians and patients will be examined using outcomes including clinical benefit, progression-free survival, overall survival, time to treatment failure, time to chemotherapy, response, health-related quality of life, and adverse events.
Conclusion: Evaluation of the efficacy and safety of secondary endocrine therapy for breast cancer with low sensitivity to initial endocrine therapy will provide information for evidence-based selection of appropriate secondary endocrine therapy. The results will also clarify the remaining clinical issues to be resolved and provide a foundation for planning of future clinical research.