Background: HER2-positive breast cancer is an aggressive subtype associated with poor outcomes, particularly in low- and middle-income countries where access to targeted therapy is limited. Despite the growing burden of breast cancer in Kenya, comprehensive data on the clinical characteristics of HER2-positive patients remain scarce. Objectives: This study aimed to describe the clinical characteristics of HER2-positive breast cancer patients treated at Moi Teaching and Referral Hospital (MTRH) in Kenya between January 2018 and December 2023. Methods: This retrospective cohort study employed a census approach, enrolling 300 histologically confirmed HER2-positive breast cancer patients. Data were extracted from medical records using a standardized abstraction tool. Descriptive statistics were used to summarize demographic characteristics, reproductive history, comorbidities, presenting symptoms, and duration of symptoms before diagnosis. Results: The majority of patients (56.0%) were under 50 years, with 32.3% under 40 years. Most patients were married (78.3%) and came from the western region of Kenya, with Uasin Gishu County contributing 18.0% of patients. Housewives (28.0%) and farmers (16.0%) were the predominant occupational groups. Menopausal status was nearly equally distributed between pre-menopausal (45.0%) and post-menopausal (52.7%) patients. A positive family history of breast cancer was reported by only 5.7% of patients. Hypertension (18.7%) and diabetes mellitus (8.3%) were the most common comorbidities. Breast lump was the predominant presenting symptom (97.0%), followed by pain (27.7%), skin changes (18.3%), and nipple discharge (16.7%). The majority of patients (69.3%) presented with symptoms lasting 3 months or longer, with 19.0% having symptoms for more than one year before diagnosis. Conclusion: HER2-positive breast cancer at MTRH predominantly affects young women with significant diagnostic delays. The high prevalence of advanced-stage presentation and comorbidities underscores the need for enhanced early detection strategies, improved breast cancer awareness, and comprehensive multidisciplinary management approaches in Kenya.
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