Abstract
This study is a retrospective study using real-world data to compare treatment patterns with the guidelines for drug administration of the National List of Essential Medicine (NLEM) category E(2), and to compare effectiveness with the efficacy of clinical studies. This study focused on the treatment pattern and effectiveness of trastuzumab for early breast cancer (ICD-10 C50). Data were retrieved from the reimbursement database of the NLEM category E(2) during fiscal year 2015-2018. Time to follow-up was truncated at the end of fiscal year 2018. The data were analyzed by using descriptive statistics and non-parametric with Kaplan-Meier method. As a result, there were a total of 2,492 early-stage breast cancer patients, mostly between the ages of 50-59 years (37%), with a median follow-up of 34.98 months (interquartile range 16.75 months). The majority of patients received trastuzumab in accordance with the NLEM category E(2) guideline, 1,996 cases (80%) received drug less than 18 treatment cycles and 2,217 cases (89%) received drug less than 14 months. Subgroup analysis of the less than 14 months found 942 patients (38%) received the drug less than 12 months. Analyses of real-world effectiveness by using survival analysis in all trastuzumab patients found a 4-year survival rate of 80.02% (95% CI: 77.69-81.62); 78.74 % (95% CI: 76.36-80.90) for less than 18 treatment cycles, and 85.07 % (95% CI: 82.24-87.48) for the 12-14 months. These rates were lower than the efficacy reported from randomized controlled trials. Therefore, the present study of real-life data analysis concludes that most of patients received the trastuzumab in line with the NLEM E(2) guideline. Non-adherence may result in reducing the effectiveness of treatment lower than the efficacy from the RCT. However, this study did not explain the reason of non-adherence due to lack of important data, such as responses to treatment, recurrence and occurrence of side effects from drug use.
