Factors associated with disease progression among hormone receptor-positive breast cancer patients treated with endocrine therapy: A 5-year cross-sectional, retrospective follow-up study

Abstract

Endocrine therapy (ET) has shown clinical benefts for hormone receptor (HR)-positive breast cancer (BCa) patients. However, it is important to monitor patients’ response to ET. The present study aims to identify the factors associated with disease progression 1 year after ET initiation in a sample of HR-positive BCa patients at Hospital Sultanah Nur Zahirah, a Malaysian public hospital. Patients were identifed from the Cancer Registry of the Terengganu State Health Department. Female patients aged ≥18 years, diagnosed with HR-positive BCa during the period from 2011 to 2014, and who were prescribed with at least one type of ET were included and retrospectively followed-up for 5 years. Disease progression that occurred after 1 year of ET was recorded. Adherence was measured using the medication possession ratio (MPR). Of all 103 BCa patients included in the study, 31.1% had disease progression after 1 year of ET initiation. Late-stage BCa, distant metastasis at diagnosis, MPR value of <0.8 in the frst year of treatment, high comorbidity, and a history of complementary and alternative medicine use were associated with disease progression. Adherence to ET should be emphasized in BCa patients. There is a need to encourage women to seek early treatment for BCa.