Trastuzumab Emtansine (T-DM1) and Survival Outcomes in HER2-Positive Metastatic Breast Cancer: A Single-Center Experience

Abstract

Purpose: To describe real-world outcomes of trastuzumab emtansine (T-DM1) in patients with HER2-positive metastatic breast cancer and to explore clinical factors associated with survival. Methods: This retrospective single-center cohort included women with HER2-positive metastatic breast cancer who received at least one cycle of T-DM1 between March 2020 and January 2025 at Adana City Training and Research Hospital. Demographic, clinicopathologic and treatment-related data were collected from electronic health records. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan–Meier method, and prespecified subgroups were compared using two-sided log-rank tests. Results: Sixty-one patients were included; median age at T-DM1 initiation was 52 years (range, 34–82). All had received prior trastuzumab-based therapy, most had been treated with taxanes and pertuzumab, and T-DM1 was used predominantly as second-line treatment. Median PFS was 8.1 months (95% CI, 6.9–9.2) and median OS was 24.5 months (95% CI, 22.7–26.3). The objective response rate was 55.7%, with stable disease in 8.2%. ECOG performance status was the strongest prognostic factor. Patients with ECOG 0–1 had longer PFS (10.9 vs 5.9 months) and OS (30.3 vs 10.5 months) than those with ECOG 2. Median OS was shorter in patients with brain/CNS metastases than in those without (8.9 vs 25.1 months), while PFS did not differ meaningfully between these groups. Conclusion: In this real-world cohort, T-DM1 provided PFS, OS and response rates comparable to those reported in clinical trials, in a population previously treated with trastuzumab- and pertuzumab-based first-line therapy and receiving T-DM1 predominantly as second-line treatment. Performance status and brain/CNS involvement were key determinants of outcome. These findings emphasize the prognostic role of performance status and the continuing need for more effective approaches in patients with brain/CNS metastases.

Keywords

• T-DM1
• HER2-positive breast cancer
• metastatic breast cancer

HER2-pozitif metastatik meme kanserinde trastuzumab emtansine (T-DM1) ve sağkalım sonuçları: tek merkez deneyimi

Abstract

Amaç: HER2-pozitif metastatik meme kanserli hastalarda trastuzumab emtansinin (T-DM1) gerçek yaşam sonuçlarının ortaya konulması ve sağkalımla ilişkili klinik faktörlerin değerlendirilmesi amaçlandı. Gereç ve Yöntem: Bu retrospektif tek merkezli kohorta, 2020 Mart ile 2025 Ocak tarihleri arasında Adana Şehir Eğitim ve Araştırma Hastanesi’nde en az bir kür T-DM1 alan HER2-pozitif metastatik meme kanserli kadın hastalar dahil edildi. Demografik, klinik-patolojik ve tedaviye ilişkin veriler elektronik dosyalardan elde edildi. Progresyonsuz sağkalım (PFS) ve genel sağkalım (OS) Kaplan–Meier yöntemi ile hesaplandı; önceden belirlenmiş alt gruplar iki yönlü log-rank testleri ile karşılaştırıldı. Bulgular: Çalışmaya 61 hasta dahil edildi; T-DM1 başlangıcında ortanca yaş 52 idi (34–82). Tüm hastalar daha önce trastuzumab temelli tedavi almıştı; hastaların çoğu taksan ve pertuzumab da kullanmıştı ve T-DM1 büyük ölçüde ikinci basamakta uygulanmıştı. Ortanca PFS 8,1 ay (GA %95, 6,9–9,2) ve ortanca OS 24,5 ay (GA %95, 22,7–26,3) olarak bulundu. Objektif yanıt oranı %55,7, stabil hastalık oranı %8,2 idi. ECOG performansı en güçlü prognostik faktör olarak saptandı. ECOG 0–1 olan hastalarda PFS (10,9’a karşı 5,9 ay) ve OS (30,3’e karşı 10,5 ay) ECOG 2 olan hastalara göre daha uzundu. Beyin/MSS metastazı olan hastalarda ortanca OS daha kısaydı (8,9’a karşı 25,1 ay); buna karşın PFS bakımından anlamlı bir fark yoktu. Sonuç: Bu gerçek yaşam kohortunda, daha önce trastuzumab temelli ve çoğunlukla pertuzumab içeren birinci basamak tedavi almış ve T-DM1’i ağırlıklı olarak ikinci basamakta kullanmış bir hasta grubunda, klinik çalışmalardakine benzer PFS, OS ve yanıt oranları saptanmıştır. Performans durumu ve beyin/MSS tutulumu sağkalım açısından temel belirleyiciler olarak öne çıkmıştır. Bu bulgular, performans durumunun prognostik önemini ve beyin/MSS metastazı olan hastalarda daha etkili tedavi yaklaşımlarına duyulan gereksinimi vurgulamaktadır.

Keywords

• T-DM1
• HER2-pozitif meme kanseri
• metastatik meme kanseri

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