Determinants of adherence to therapies among Malaysian women with breast cancer: MyBCC Cohort

Abstract

Background: Breast cancer therapies have been progressively advancing to improve the breast cancer survival over the last few decades. However, non-adherence to cancer treatments has shown to be associated with reduced treatment effectiveness, increased mortality, and increased health care costs. The aim of the study is to understand the determinants of adherence to therapies among Malaysian breast cancer patients. Methods: This was a secondary analysis of all newly diagnosed Malaysian breast cancer patients recruited into a prospective cohort study in Universiti Malaya Medical Centre, MyBCC cohort, from 1 st February 2012 to 31 st December 2015. The MyBCC cohort study has ethics approval, MEC number 896.150. The treatment options (surgery, chemotherapy, radiotherapy, and overall therapies), surgical options, socio-demographic characteristics, clinical signs and symptoms, traditional and complementary medicine, and psychosocial assessments were measured using Hospital Anxiety and Depression Scale (HADS) and Multidimensional Scale of Perceived Social Support (MSPSS). Results : In total, 467 patients were analysed. The adherence to surgery was 93.8%, chemotherapy 87.7%, radiotherapy 89.1%, and overall therapies 65.8% respectively. Breast conserving surgery was associated with adherence to surgery compared to mastectomy (adjusted OR 5.48 [95% CI 1.00, 30.09], p = 0.034), radiotherapy (adjusted OR 5.44 [95% CI 1.17, 25.16], p = 0.030) and overall therapies (adjusted OR 2.45 [95% CI 1.04, 5.78], p = 0.041). Time from diagnosis to surgery of less than 60 days was associated with adherence to surgery (adjusted OR 49.98 [95% CI 8.47, 289.05], p less than 0.0001) and overall therapies (adjusted OR 9.38 [95% CI 1.26, 69.73], p = 0.029). Adherence to chemotherapy associated with no surgery (adjusted OR 0.15 [95% CI 0.03, 0.70], p = 0.016). Adherence to radiotherapy was associated with financial reimbursement (adjusted OR 4.34 [95% CI 1.03, 18.26], p = 0.045) and adherence to chemotherapy (adjusted OR 0.01 [95% CI 0.00, 0.04], p less than 0.0001). Conclusion : The study demonstrated excellent adherence to breast cancer surgery management. Surgical options and time from diagnosis to surgery affect the adherence to surgery and the systemic treatments. Financial reimbursement and adherence to chemotherapy were predictors of adherence to radiotherapy. Timely surgery and financial resource remain major contributor to treatment adherence. CAM and psychosocial factors did not contribute to treatment adherence in this study. This study was supported by postgraduate research grant from University Malaya. MEC number 896.150.