Yasuaki Sagara1,2, Masahiro Takada3, Yasuyo Ohi4, Shoichiro Ohtani5, Sasagu Kurozumi6, Kenichi Inoue7, Yoshimasa Kosaka8, Masaya Hattori9, Toshinari Yamashita10, Shintaro Takao11, Nobuaki Sato12, Hiroji Iwata9, Masafumi Kurosumi13, Masakazu Toi3. 1. Department of Breast Surgery, Kyoto University Graduate School of Medicine, 54 Kawaracho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan. yasuaki@sagara.or.jp. 2. Department of Breast Surgical Oncology, Social Medical Cooperation Hakuaikai, Kagoshima, Japan. yasuaki@sagara.or.jp. 3. Department of Breast Surgery, Kyoto University Graduate School of Medicine, 54 Kawaracho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan. 4. Department of Pathology, Social Medical Cooperation Hakuaikai, Kagoshima, Japan. 5. Department of Breast Surgery, Hiroshima City Hospital, Hiroshima, Japan. 6. Department of General Surgical Science, Gunma University Graduate School of Medicine, Gunma, Japan. 7. Department of Breast Oncology, Saitama Cancer Center, Saitama, Japan. 8. Department of Breast and Endocrine Surgery, Kitasato University School of Medicine, Sagamihara, Japan. 9. Department of Breast Oncology, Aichi Cancer Center Hospital, Nagoya, Japan. 10. Department of Breast and Endocrine Surgery, Kanagawa Cancer Center, Yokohama, Japan. 11. Department of Breast Surgery, Hyogo Cancer Center, Akashi, Japan. 12. Department of Breast Surgery, Niigata Cancer Center Hospital, Niigata, Japan. 13. Department of Pathology, Saitama Cancer Center, Saitama, Japan.
Abstract
PURPOSE: While human epidermal growth factor receptor 2 (HER2) target therapies have significantly improved the prognosis of patients with HER2-enriched breast cancer, differing clinical benefits and gene expression analyses suggest a divergent HER2 subgroup. We aimed to investigate whether the basal HER2 subtype of breast cancer has distinguished characteristics. METHODS: We performed a substudy by using data from a retrospective multi-institutional cohort of JBCRG-C03. Between 2001 and 2011, we identified 184 eligible patients who received concurrent neo-adjuvant chemotherapy (NAC) with trastuzumab for hormone receptor-negative and HER2-positive breast cancer. We defined basal HER2 subtype breast cancer as HER2-positive, ER/PgR-negative, and basal markers (EGFR, CK14 or CK5/6) positive by immunohistochemistrical evaluation. The pathologic complete response (pCR) and disease-free survival (DFS) rates were compared between the two subtypes. RESULTS: A total of 127 (69.0%) patients achieved pCR after NAC and 29 (15.8%) patients experienced events of DFS within a 42 month median follow-up period (interquartile range 26-58 months). Although the basal HER2 subtype was related with poor DFS (3 year DFS: non-basal HER2, 95.0%; basal HER2, 86.9%; adjusted HR 3.4; 95% CI 1.2-14.5), neither the subtype (pCR: non-basal HER2, 75%; basal HER2, 66.7%; adjusted OR 0.60; 95% CI 0.27-1.28) nor the degree of expression of basal markers was significantly related with the pCR rate. CONCLUSION: Basal HER2 phenotype showed poor DFS, but equivalent pCR rate after concurrent neo-adjuvant chemotherapy with trastuzumab. A different treatment approach to basal-HER2 type is needed even for cases that achieved adequate clinical response after NAC.
PURPOSE: While humanepidermal growth factor receptor 2 (HER2) target therapies have significantly improved the prognosis of patients with HER2-enriched breast cancer, differing clinical benefits and gene expression analyses suggest a divergent HER2 subgroup. We aimed to investigate whether the basal HER2 subtype of breast cancer has distinguished characteristics. METHODS: We performed a substudy by using data from a retrospective multi-institutional cohort of JBCRG-C03. Between 2001 and 2011, we identified 184 eligible patients who received concurrent neo-adjuvant chemotherapy (NAC) with trastuzumab for hormone receptor-negative and HER2-positive breast cancer. We defined basal HER2 subtype breast cancer as HER2-positive, ER/PgR-negative, and basal markers (EGFR, CK14 or CK5/6) positive by immunohistochemistrical evaluation. The pathologic complete response (pCR) and disease-free survival (DFS) rates were compared between the two subtypes. RESULTS: A total of 127 (69.0%) patients achieved pCR after NAC and 29 (15.8%) patients experienced events of DFS within a 42 month median follow-up period (interquartile range 26-58 months). Although the basal HER2 subtype was related with poor DFS (3 year DFS: non-basal HER2, 95.0%; basal HER2, 86.9%; adjusted HR 3.4; 95% CI 1.2-14.5), neither the subtype (pCR: non-basal HER2, 75%; basal HER2, 66.7%; adjusted OR 0.60; 95% CI 0.27-1.28) nor the degree of expression of basal markers was significantly related with the pCR rate. CONCLUSION: Basal HER2 phenotype showed poor DFS, but equivalent pCR rate after concurrent neo-adjuvant chemotherapy with trastuzumab. A different treatment approach to basal-HER2 type is needed even for cases that achieved adequate clinical response after NAC.
Authors: Moqing Liu; Rebecca Smith; Tiera Liby; Kami Chiotti; Claudia S López; James E Korkola Journal: Breast Cancer Res Date: 2022-03-05 Impact factor: 6.466