Pathologic Response and Survival Outcomes on HER2-Low vs. HER2-Zero in Breast Cancer Receiving Neoadjuvant Chemotherapy
<i>Background and Objectives</i>: The clinical value of HER2-low breast cancer (BC), defined by immunohistochemistry (IHC) scores of 1+ or 2+/ISH-negative without HER2 amplification, remains unclear in the neoadjuvant setting. This study aimed to determine whether HER2-low and HER2-zero...
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MDPI AG
2025-06-01
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| author | Rumeysa Colak Caner Kapar Ezgi Degerli Seher Yildiz Tacar Aysegul Akdogan Gemici Nursadan Gergerlioglu Serdar Altinay Mesut Yilmaz |
| author_facet | Rumeysa Colak Caner Kapar Ezgi Degerli Seher Yildiz Tacar Aysegul Akdogan Gemici Nursadan Gergerlioglu Serdar Altinay Mesut Yilmaz |
| author_sort | Rumeysa Colak |
| collection | DOAJ |
| description | <i>Background and Objectives</i>: The clinical value of HER2-low breast cancer (BC), defined by immunohistochemistry (IHC) scores of 1+ or 2+/ISH-negative without HER2 amplification, remains unclear in the neoadjuvant setting. This study aimed to determine whether HER2-low and HER2-zero tumors differ in pathological complete response (pCR) rates and disease-free survival (DFS) among early-stage breast cancer patients undergoing neoadjuvant chemotherapy (NAC). <i>Materials and Methods</i>: We retrospectively analyzed 134 early BC patients treated with NAC between 2017 and 2023. Patients were categorized as HER2-zero (IHC 0) or HER2-low (IHC 1+ or 2+/ISH–). The primary endpoint was total pCR (tpCR); secondary endpoints included breast (bpCR), nodal (npCR), and radiologic complete response (rCR), alongside DFS analysis stratified by hormone receptor (HR) status. <i>Results</i>: Of the cohort, 91 patients (67.9%) were HER2-zero and 43 (32.1%) were HER2-low. There was no statistically significant difference in tpCR (26.4% vs. 27.9%, <i>p</i> = 0.852), bpCR (28.6% vs. 30.2%, <i>p</i> = 0.843), npCR (37.4% vs. 32.6%, <i>p</i> = 0.588), and rCR (23.1% vs. 30.2%, <i>p</i> = 0.374) between HER2-zero and HER2-low groups. DFS did not significantly differ between HER2-zero and HER2-low groups overall (<i>p</i> = 0.714), nor within HR-positive (<i>p</i> = 0.540) or TNBC (<i>p</i> = 0.523) subgroups. <i>Conclusions</i>: HER2-low tumors demonstrated similar pathological responses and survival outcomes compared to HER2-zero tumors. While a HER2-low status does not appear to define a distinct biological subtype in early BC, it remains a relevant classification for emerging HER2-targeted therapies, needing further investigation in prospective studies. |
| format | Article |
| id | doaj-art-48af0af062d647dba279c54f045225d2 |
| institution | Kabale University |
| issn | 1010-660X 1648-9144 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | MDPI AG |
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| series | Medicina |
| spelling | doaj-art-48af0af062d647dba279c54f045225d22025-08-20T03:35:38ZengMDPI AGMedicina1010-660X1648-91442025-06-01617116810.3390/medicina61071168Pathologic Response and Survival Outcomes on HER2-Low vs. HER2-Zero in Breast Cancer Receiving Neoadjuvant ChemotherapyRumeysa Colak0Caner Kapar1Ezgi Degerli2Seher Yildiz Tacar3Aysegul Akdogan Gemici4Nursadan Gergerlioglu5Serdar Altinay6Mesut Yilmaz7Department of Medical Oncology, Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul 34147, TurkeyDepartment of Medical Oncology, Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul 34147, TurkeyDepartment of Medical Oncology, Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul 34147, TurkeyDepartment of Medical Oncology, Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul 34147, TurkeyDepartment of Radiology, Istanbul Medipol Mega University Hospital, Istanbul 34214, TurkeyDepartment of Pathology, Faculty of Medicine, Arel University, Istanbul 34010, TurkeyDepartment of Pathology, Hamidiye Faculty of Medicine, University of Health Sciences, Istanbul 34371, TurkeyDepartment of Medical Oncology, Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul 34147, Turkey<i>Background and Objectives</i>: The clinical value of HER2-low breast cancer (BC), defined by immunohistochemistry (IHC) scores of 1+ or 2+/ISH-negative without HER2 amplification, remains unclear in the neoadjuvant setting. This study aimed to determine whether HER2-low and HER2-zero tumors differ in pathological complete response (pCR) rates and disease-free survival (DFS) among early-stage breast cancer patients undergoing neoadjuvant chemotherapy (NAC). <i>Materials and Methods</i>: We retrospectively analyzed 134 early BC patients treated with NAC between 2017 and 2023. Patients were categorized as HER2-zero (IHC 0) or HER2-low (IHC 1+ or 2+/ISH–). The primary endpoint was total pCR (tpCR); secondary endpoints included breast (bpCR), nodal (npCR), and radiologic complete response (rCR), alongside DFS analysis stratified by hormone receptor (HR) status. <i>Results</i>: Of the cohort, 91 patients (67.9%) were HER2-zero and 43 (32.1%) were HER2-low. There was no statistically significant difference in tpCR (26.4% vs. 27.9%, <i>p</i> = 0.852), bpCR (28.6% vs. 30.2%, <i>p</i> = 0.843), npCR (37.4% vs. 32.6%, <i>p</i> = 0.588), and rCR (23.1% vs. 30.2%, <i>p</i> = 0.374) between HER2-zero and HER2-low groups. DFS did not significantly differ between HER2-zero and HER2-low groups overall (<i>p</i> = 0.714), nor within HR-positive (<i>p</i> = 0.540) or TNBC (<i>p</i> = 0.523) subgroups. <i>Conclusions</i>: HER2-low tumors demonstrated similar pathological responses and survival outcomes compared to HER2-zero tumors. While a HER2-low status does not appear to define a distinct biological subtype in early BC, it remains a relevant classification for emerging HER2-targeted therapies, needing further investigation in prospective studies.https://www.mdpi.com/1648-9144/61/7/1168HER2-lowbreast cancerneoadjuvant chemotherapypathologic complete responsedisease-free survivalhormone receptor status |
| spellingShingle | Rumeysa Colak Caner Kapar Ezgi Degerli Seher Yildiz Tacar Aysegul Akdogan Gemici Nursadan Gergerlioglu Serdar Altinay Mesut Yilmaz Pathologic Response and Survival Outcomes on HER2-Low vs. HER2-Zero in Breast Cancer Receiving Neoadjuvant Chemotherapy Medicina HER2-low breast cancer neoadjuvant chemotherapy pathologic complete response disease-free survival hormone receptor status |
| title | Pathologic Response and Survival Outcomes on HER2-Low vs. HER2-Zero in Breast Cancer Receiving Neoadjuvant Chemotherapy |
| title_full | Pathologic Response and Survival Outcomes on HER2-Low vs. HER2-Zero in Breast Cancer Receiving Neoadjuvant Chemotherapy |
| title_fullStr | Pathologic Response and Survival Outcomes on HER2-Low vs. HER2-Zero in Breast Cancer Receiving Neoadjuvant Chemotherapy |
| title_full_unstemmed | Pathologic Response and Survival Outcomes on HER2-Low vs. HER2-Zero in Breast Cancer Receiving Neoadjuvant Chemotherapy |
| title_short | Pathologic Response and Survival Outcomes on HER2-Low vs. HER2-Zero in Breast Cancer Receiving Neoadjuvant Chemotherapy |
| title_sort | pathologic response and survival outcomes on her2 low vs her2 zero in breast cancer receiving neoadjuvant chemotherapy |
| topic | HER2-low breast cancer neoadjuvant chemotherapy pathologic complete response disease-free survival hormone receptor status |
| url | https://www.mdpi.com/1648-9144/61/7/1168 |
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