Compliance with Oral Hormonal Therapy for Breast Cancer at Oman National Oncology Center; Descriptive Study.

Introduction: Breast cancer is the commonest cancer amongst females. The incidence of breast cancer is estimated to be around 260K yearly. Oral hormonal medication is an essential part of the management of breast cancer for hormone receptor-positive patients. Adjuvant hormonal medication is recommended to be taken daily for 5-10 years. Adjuvant hormonal medication reduces mortality by 30% and the recurrence rate in receptor-positive patients.

Patients and methods: This study's primary goal is to evaluate the rate of nonadherence to Endocrine Therapy for hormone receptor-positive breast cancer patients at Oman National Oncology Center. This study included patients taking hormonal therapy (either with Tamoxifen or Aromatase inhibitor) and presented for regular followup between June 2019 and February 2020 at the National oncology center, Oman. Data was collected using a written questionnaire. Descriptive analysis was done by using SPSS. A cross-sectional descriptive study for patients taking oral hormonal therapy. 131 patients were included.

Results: One hundred thirty-one patients were included, Tamoxifen was used by 73 (55.73%). 71 (54%) of breast surgery was "WLE" The majority of patients 95 (72.5%) did not identify a specific reason for non-compliance. The most commonly reported adverse effects were musculoskeletal symptoms by 75 patients (57.3%), with other reported side effects included hot flashes (33.6%), anxiety (30.5%), gynecological toxicity (29.8%), decreased concentration (19.1%), neurological symptoms (16%), and depression (9.9%).

Discussion: We reported that patients with hormone receptor-positive breast cancer have a high adherence rate to the medication than developing countries; selfreported non-compliance to oral hormonal medication is 41.22% below the average of non-compliance to chronic disease therapy of developing countries as WHO report. Medical insurance, unemployment, or drug cost is not a cause for non-compliance to medication.

Conclusion: The self-reported nonadherence to oral hormonal medication is (41,22%). Most of the patients (72.5%) did not report a specific cause for non-adherent to medication. Close follow-up is recommended increasing compliance to medication.