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Poster display session

3594 - Durable Complete Response in HER2-Positive Breast Cancer: A Multicenter Retrospective Analysis


11 Sep 2017


Poster display session


Breast Cancer


Akihiko Shimomura


Annals of Oncology (2017) 28 (suppl_5): v74-v108. 10.1093/annonc/mdx365


A. Shimomura1, N. Niikura2, Y. Fukatsu3, M. Sawaki4, R. Ogiya2, H. Yasojima5, T. Fujisawa6, M. Yamamoto7, M. Tsuneizumi8, A. Kitani9, J. Watanabe10, A. Matsui11, Y. Takahashi12, S. Takashima13, T. Shien12, K. Tamura1, S. Saji14, N. Masuda15, Y. Tokuda2, H. Iwata4

Author affiliations

  • 1 Department Of Breast And Medical Oncology, National Cancer Center Hospital, 104-0045 - Tokyo/JP
  • 2 Department Of Breast And Endocrine Surgery, Tokai University School of Medicine Isehara Campus, 259-1193 - Isehara/JP
  • 3 Department Of Breast Surgical Oncology, St. Luke’s International Hospital, Tokyo/JP
  • 4 Department Of Breast Oncology, Aichi Cancer Center Hospital, Nagoya/JP
  • 5 Department Of Surgery, Breast Oncology, National Hospital Organization Osaka National Hospital, Osaka/JP
  • 6 Department Of Breast Oncology, Gunma Prefectural Cancer Center, 373-8550 - Gunma/JP
  • 7 Department Of Breast Surgery, National Hospital Organization Hokkaido Cancer Center, Sapporo/JP
  • 8 Department Of Breast Surgery, Shizuoka General Hospital, Shizuoka/JP
  • 9 Department Of Breast Surgery, Sagara Hospital, Kagoshima/JP
  • 10 Department Of Breast Oncology, Shizuoka Cancer Center, 411-8777 - Shizuoka/JP
  • 11 Department Of Surgery, National Hospital Organization Tokyo Medical Center, 152-8902 - Tokyo/JP
  • 12 Department Of Breast And Endocrine Surgery, Okayama University Hospital, Okayama/JP
  • 13 Department Of Breast Oncology, National Hospital Organization Shikoku Cancer Center, 791-0280 - Matsuyama/JP
  • 14 Department Of Medical Oncology, Fukushima Medical University, School of Medicine, Fukushima/JP
  • 15 Department Of Surgery, Breast Oncology, National Hospital Organization Osaka National Hospital, 540-0006 - Osaka/JP


Abstract 3594


Though advanced and metastatic epidermal growth factor receptor 2 (HER2)-positive disease is not curable, a small proportion of patients with HER2-positive metastatic breast cancer remain in prolonged complete remission with anti-HER2 treatment. We hypothesized that some cases of human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer may be curable by trastuzumab. In this large, multicenter retrospective study, we aimed to assess the long-term outcomes for patients with a durable response to trastuzumab.


We retrospectively evaluated the data of patients diagnosed with HER2-positive metastatic breast cancer who received trastuzumab for more than 2 years as the first-line treatment. Patients diagnosed between April 1, 2001 and December 31, 2014 at 19 institutions in Japan were included in the analysis.


A total of 108 patients were evaluated. Sixteen were met to exclusion criteria. The median follow-up length was 7.7 years. Disease progression occurred in 44/108 (40.7%) patients and 13/108 (12%) patients died. The median progression-free survival was 11.2 years, and as more than 80% of patients were alive 10 years after metastatic breast cancer diagnosis. Of the 108 patients, 57 achieved a clinical complete response. Trastuzumab therapy was interrupted for 27 (47.4%) of these patients (based on the doctor’s recommendation for 19 patients, owing to adverse events for 4 patients, owing to unknown reasons for 3 patients, and at the request of 1 patient). Disease progression occurred in 4 of the 27 patients after the interruption of trastuzumab treatment. The median duration of trastuzumab therapy for all 27 patients was 5.1 years (0.9-9.3 years).


In conclusion, we found that some patients showed no evidence of disease after the interruption of trastuzumab therapy. Discontinuation of maintenance trastuzumab in this patient population after a limited time should be explored cautiously while awaiting a global collaborative effort for a randomized trial.

Clinical trial identification

Legal entity responsible for the study





A. Shimomura: Research funds from AstraZeneca. J. Watanabe: Honoraria from AstraZeneca Japan, Chugai Pharmaceuticals, Eisai, Novartis Pharma Japan, Taiho pharmaceutical. Advisory board member of AstraZeneca Japan, Eisai. A. Matsui: Lecture Fee: Chugai, Daiichi Sankyo, Eisai, AstraZeneca, Kyowa Kirin Pharmaceutical. Research Funds: Chugai, Daiichi Sankyo, Eisai, Takeda Pharmaceutical, Taiho Pharmaceutical. T. Shien: Lecture fee from AstraZeneca, Novartis, Eizai, Chugai. K. Tamura: Research funds from AstraZeneca, Daiichi Sankyo, Pfizer, MSD. S. Saji: Honoraria from AstraZeneca, Chugai Pharmaceutical, Eisai, Novartis Pharma. Research funds from AstraZeneca and Chugai Pharmaceutical. N. Masuda: Research funds from Chugai and Eisai. Honorarium from Chugai and AstraZeneca. Y. Tokuda: Lecture fee: Pfizer, AstraZeneca, Novartis, Galderma, Kyowa Hakko Kirin. Manuscript fee: Kyowa Hakko Kirin, Daiichi Sankyo. Research funds: Taiho, Eisai, Nippon Kayaku, Chugai, Kyowa Hakko Kirin, Takeda, Novartis, CSPOR. Consulting fee: Meiji. All other authors have declared no conflicts of interest.

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