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Clinical Paper Volume 17 Issue 4
Prevalence and manifestations of HER2-low breast cancer in patients with unresectable and/or metastatic disease progressing on anticancer therapy: a retrospective study in the GCC region
Shereef Elsamany, Salha BJ Al Bader, Abdullah Altwairgi, Abdulwahab Altourah, Aref Chehal, Aydah AlAwadhi, Diaeddine Trad, Fathi Azribi, Mishari Alzahrani, Syed Hammad Tirmazy, Sharif Kullab, Syed Hammad Tirmazy, Mai Behairy, Amgad Kamal
National Center for Cancer Care and Research, Doha, Qatar.
AstraZeneca Gulf Cooperation Council, Dubai, UAE
King Abdullah Medical City, Makkah, KSA
King Fahad Medical City, Riyadh, KSA
Kuwait Cancer Control Center, Kuwait
Sheikh Shakhbout Medical City, Abu Dhabi, UAE
Tawam Hospital, Al Ain, UAE
American Hospital, Dubai, UAE
King Faisal Specialist Hospital and Research Center, Riyadh, KSA
Dubai Hospital, Dubai, UAE
King Khaled University Hospital, Riyadh, KSA
Received: June 24, 2026 | Published: August 11, 2026
Citation: Bader SBJA, Altwairgi A, Altourah A, et al. Prevalence and manifestations of HER2-low breast cancer in patients with unresectable and/or metastatic disease progressing on anticancer therapy: a retrospective study in the GCC region. J Cancer Prev Curr Res. 2026;17(4):128‒137 DOI: 10.15406/jcpcr.2026.17.00620
Abstract
Background: The traditional binary classification of human epidermal growth factor receptor 2 (HER2) status in breast cancer (BC) has been challenged by recognition of the HER2-low subtype and the clinical benefits of novel HER2-targeted agents, such as trastuzumab deruxtecan. This study aimed to describe the prevalence, clinical features, treatment patterns, and outcomes of HER2-low BC in the Gulf Cooperation Council (GCC) region to identify the current unmet need for more effective treatment for this disease subgroup. Methods: A retrospective, observational study included 500 patients diagnosed with HER2- negative, unresectable, and/or metastatic BC (mBC) from January 1, 2018, to December 31, 2022. We analyzed data from medical records across the United Arab Emirates, the Kingdom of Saudi Arabia, Qatar, and Kuwait. Results: Among the 500 patients enrolled, 332 (66.4%, 95% CI: 62.3%-70.5%) were identified as HER2-low BC patients. The mean age at diagnosis was 53.4 years. Most patients were postmenopausal (57.8%), had invasive ductal carcinoma (86.4%), and were estrogen receptor-positive (93.7%). A majority (73.3%) were diagnosed at stage IV , with bone (72.3%) and lung (41.9%) being the most common metastatic sites. Nearly all patients received first-line (1L) therapy, most commonly CDK4/6 inhibitors with hormonal therapies (51.4%) or chemotherapy (17.4%). Combination therapies were primarily used in the first, second, and third lines before switching to single-agent therapy. Treatment discontinuation due to progression ranged from 28.3% to 38.6% across lines; adverse events accounted for up to 13% of the cases. Nearly 47.7% of patients experienced disease progression, and 7.6% relapsed after 1L therapy. The median real-world progression-free survival (rwPFS) was 16.4 months for 1L and 6.8 months for second-line therapies. Conclusion: HER2-low subtype constitutes a significant proportion of mBC cases in the GCC region. Despite the available therapies, rwPFS results highlighted the need for more effective treatment approaches to improve patient outcomes.
Keywords: breast neoplasms, neoplasm metastasis, receptor, erbB-2, trastuzumab deruxtecan
©2026 Bader, et al. This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and build upon your work non-commercially.