Adjuvant trastuzumab without chemotherapy for treating early HER2-positive breast cancer in older patients: A propensity score-adjusted analysis of a prospective cohort study

Masataka Sawaki; Naruto Taira; Yukari Uemura; Tsuyoshi Saito; Shinichi Baba; Kokoro Kobayashi; Hiroaki Kawashima; Michiko Tsuneizumi; Noriko Sagawa; Hiroko Bando; Masato Takahashi; Miki Yamaguchi; Tsutomu Takashima; Takahiro Nakayama; Masahiro Kashiwaba; Toshiro Mizuno; Yutaka Yamamoto; Hiroji Iwata; Tatsuya Toyama; Koichiro Tsugawa; Takuya Kawahara; Hirofumi Mukai; RESPECT study group

doi:10.1016/j.breast.2022.10.017

Adjuvant trastuzumab without chemotherapy for treating early HER2-positive breast cancer in older patients: A propensity score-adjusted analysis of a prospective cohort study

Breast. 2022 Dec:66:245-254. doi: 10.1016/j.breast.2022.10.017. Epub 2022 Nov 7.

Authors

Masataka Sawaki¹, Naruto Taira², Yukari Uemura³, Tsuyoshi Saito⁴, Shinichi Baba⁵, Kokoro Kobayashi⁶, Hiroaki Kawashima⁷, Michiko Tsuneizumi⁸, Noriko Sagawa⁹, Hiroko Bando¹⁰, Masato Takahashi¹¹, Miki Yamaguchi¹², Tsutomu Takashima¹³, Takahiro Nakayama¹⁴, Masahiro Kashiwaba¹⁵, Toshiro Mizuno¹⁶, Yutaka Yamamoto¹⁷, Hiroji Iwata¹⁸, Tatsuya Toyama¹⁹, Koichiro Tsugawa²⁰, Takuya Kawahara²¹, Hirofumi Mukai²²; RESPECT study group

Affiliations

¹ Department of Breast Oncology, Aichi Cancer Center Hospital, Nagoya, Japan. Electronic address: m-sawaki@aichi-cc.jp.
² Department of Breast and Thyroid Surgery, Kawasaki Medical School, Okayama, Japan.
³ Biostatistics Section, Department of Data Science, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan.
⁴ Department of Surgery, Japanese Red Cross Saitama Hospital, Saitama, Japan.
⁵ Department of Surgery, Sagara Hospital, Kagoshima, Japan.
⁶ Department of Medical Oncology, The Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Tokyo, Japan.
⁷ Department of Surgery, Aomori City Hospital, Aomori, Japan.
⁸ Department of Breast Surgery, Shizuoka General Hospital, Shizuoka, Japan.
⁹ Department of Breast Surgery, Kyoundo Hospital, Tokyo, Japan.
¹⁰ Department of Breast and Endocrine Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
¹¹ Department of Breast Surgery, Hokkaido University Hospital, Sapporo, Japan.
¹² Department of Breast Surgery, JCHO Kurume General Hospital, Kurume, Japan.
¹³ Department of Breast and Endocrine Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
¹⁴ Department of Breast and Endocrine Surgery, Osaka International Cancer Institute, Osaka, Japan.
¹⁵ Department of Breast Surgery, Adachi Breast Clinic, Kyoto, Japan.
¹⁶ Department of Medical Oncology, Mie University Hospital, Tsu, Japan.
¹⁷ Department of Breast and Endocrine Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
¹⁸ Department of Breast Oncology, Aichi Cancer Center Hospital, Nagoya, Japan.
¹⁹ Department of Breast Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
²⁰ Department of Breast and Endocrine Surgery, St. Marianna University School of Medicine, Kawasaki, Japan.
²¹ Clinical Research Promotion Center, The University of Tokyo Hospital, Tokyo, Japan.
²² Department of Breast and Medical Oncology, National Cancer Center Hospital East, Kashiwa, Japan.

Abstract

Purpose: To gauge the effects of treatment practices on prognosis for older patients with HER2-positive early breast cancer, particularly to determine whether adjuvant trastuzumab alone can offer benefit over no adjuvant therapy. This is a prospective cohort study which accompanies the RESPECT that is a randomized-controlled trial (RCT).

Methods: Patients who declined the RCT were treated based on the physician's discretion. We studied the 1) trastuzumab-plus-chemotherapy group, 2) trastuzumab-monotherapy group, and 3) non-trastuzumab group (no therapy or anticancer therapy without trastuzumab). The primary endpoint was disease-free survival (DFS), which was compared using the propensity-score method. Relapse-free survival (RFS) and health-related quality of life (HRQoL) were assessed.

Results: We enrolled 123 patients aged over 70 years (median: 74.5). Treatment categories were: trastuzumab-plus-chemotherapy group (n = 36, 30%), trastuzumab-monotherapy group (n = 52, 43%), and non-trastuzumab group (n = 32, 27%). The 3-year DFS was 96.7% in trastuzumab-plus-chemotherapy group, 89.2% in trastuzumab-monotherapy group, and 82.5% in non-trastuzumab group. DFS in non-trastuzumab group was lower than in trastuzumab-plus-chemotherapy and trastuzumab-monotherapy groups (propensity-adjusted hazard ratio; HR: 3.29; 95% CI: 1.15-9.39; P = 0.026). The RFS in non-trastuzumab group was lower than in trastuzumab-plus-chemotherapy and trastuzumab-monotherapy groups (propensity-adjusted HR = 7.80; 95% CI: 2.32-26.2, P < 0.0001). There were no significant intergroup differences in the proportions of patients showing HRQoL deterioration at 36 months (P = 0.717).

Conclusion: Trastuzumab-treated patients had better prognoses than patients not treated with trastuzumab without deterioration of HRQoL. Trastuzumab monotherapy could be considered for older patients who reject chemotherapy.

Keywords: Breast cancer; HER2; Older; Trastuzumab; Without chemotherapy.

Publication types

Randomized Controlled Trial

MeSH terms

Aged
Aged, 80 and over
Antineoplastic Combined Chemotherapy Protocols
Breast Neoplasms*
Chemotherapy, Adjuvant
Cohort Studies
Disease-Free Survival
Female
Humans
Neoplasm Recurrence, Local / etiology
Propensity Score
Receptor, ErbB-2
Trastuzumab / therapeutic use
Treatment Outcome

Substances

Trastuzumab
Receptor, ErbB-2