Self-reported adherence to regorafenib for metastatic colorectal cancer: A retrospective cohort study.

Abstract

783 Background: Regorafenib is an oral multikinase inhibitor for metastatic colorectal cancer (mCRC) and it is frequently involved in various adverse events. The clinical factors affecting adherence to regorafenib remain unclear. The aim of this study is to evaluate adherence to regorafenib in patients with mCRC and to identify candidate factors which might have influence on adherence to regorafenib. Methods: We evaluated 106 consecutively enrolled patients with mCRC who received regorafenib between May 18, 2013 and March 2, 2015 at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research. Adherence to regorafenib was checked by pharmacists using a self-reported treatment diary for patients at a pharmaceutical outpatient clinic. The adherence rate was defined as the number of actual intakes per 21 intakes scheduled in each cycle. We retrospectively surveyed median relative dose intensities of regorafenib and the factors deteriorating adherence across three cycles. Univariate analyses were then performed using patient socio-demographic factors and clinical factor. Multivariate analysis was performed using logistic regression. Significance levels for uni- and multivariate analyses were p < 0.2 and p< 0.05, respectively. Results: A total of 81 patients were evaluated in the study analysis. Adherence rates were 64.4% in the first cycle of regorafenib treatment, 77.4% in the second cycle, and 83.8% in the third cycle. The median relative dose intensity was 57.6%. The most common reasons for non-adherence were hand-foot skin reaction (34.3%, 331 instances), and liver dysfunction (15.3%, 148 instances). In multivariate analysis, increased non-adherence to regorafenib was significantly associated with gender (female) [odds ratio (OR) = 0.20; 95% confidence interval (CI): 0.06-0.68, p = 0.01] and adverse events ( ≥ Grade 3) [OR = 3.16; 95% CI: 1.00-9.97, p= 0.04) in the first cycle.] Conclusions: The high frequency of treatment-related hand-foot skin reaction and liver dysfunction is the main factor affecting adherence to regorafenib. Intensive supportive care in the management of these symptoms could assist adequate adherence to regorafenib.