HER2-Low Expression Predicts Improved Pathologic Response but not Disease-Free Survival in HR-Positive/HER2-Negative Breast Cancer Patients Receiving Neoadjuvant Chemotherapy HER2-Düşük Ekspresyonunun, Neoadjuvan Kemoterapi Alan HR-Pozitif / HER2-Negatif Meme Kanseri Hastalarında Patolojik Yanıta ve Sağkalıma Etkisi
Journal of Uludag University Medical Faculty, cilt.51, sa.3, ss.569-575, 2025 (Scopus, TRDizin)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 51 Sayı: 3
- Basım Tarihi: 2025
- Doi Numarası: 10.32708/uutfd.1813271
- Dergi Adı: Journal of Uludag University Medical Faculty
- Derginin Tarandığı İndeksler: Scopus, TR DİZİN (ULAKBİM)
- Sayfa Sayıları: ss.569-575
- Anahtar Kelimeler: Disease-free survival, HER2-low breast cancer, Hormone receptor-positive breast cancer, Neoadjuvant chemotherapy, Pathologic complete response
- Sağlık Bilimleri Üniversitesi Adresli: Evet
Özet
This retrospective single-center study aims to evaluate the predictive and prognostic significance of HER2-low (IHC 1+/2+ ISH–) compared with HER2-0 status in hormone receptor (HR)-positive / HER2-negative breast cancer patients treated with neoadjuvant chemotherapy (NACT). A cohort of 404 HR-positive / HER2-negative breast cancer patients treated with NACT between January 2008 and December 2019 at Bursa Uludag University was analyzed. Clinicopathologic variables, pathologic complete response (pCR), and long-term survival were assessed. Logistic regression identified independent predictors of pCR, and Cox proportional hazards modelling was used for disease-free survival (DFS). Of 404 patients, 117 (29.0%) were HER2-low and 287 (71.0%) were HER2-0. The pCR rate was significantly higher in the HER2-low group than in the HER2-0 group (9.4% vs 4.2%; p = 0.040). Multivariable logistic regression analysis revealed that HER2-low status (OR=2.88; 95% CI, 1.17–7.12; p=0.022) and a higher Ki-67 index (OR =1.03 per 1% increase; 95% CI, 1.01–1.05; p=0.003) were independent predictors of pathological complete response (pCR). The median follow-up time was 110.2 months (range, 10.5–248.9 months). The 5-and 10-year DFS rates were 85.1% and 73.7%, respectively; OS rates were 86.4% and 75.3%. In multivariable Cox regression, only pathological stage remained an independent predictor of DFS (HR=2.02; 95% CI 1.55–2.61; p<0.001), while HER2 status was not significant (HR=0.97; 95% CI 0.66–1.43; p=0.861). In conclusion, HER2-low status was associated with improved pCR but not with long-term survival. Pathologic stage remained the strongest determinant of DFS, and HER2-low appears to represent a biologic continuum within HER2-negative disease rather than a distinct prognostic subtype.