Ethnic disparities in adverse events of radiotherapy for breast cancer: A scoping review.

Abstract

e18502 Background: Ethnic disparities have been well-documented in the US as a contributor to poor outcomes following radiotherapy in ethnic minorities. The objective was to examine the intra-group and inter-group ethnic differences in adverse effects experienced by Asian breast cancer patients undergoing radiotherapy. Methods: A scoping review involving the Pubmed database was conducted. The search strategy included a combination of keywords and index terms related to Asians, breast cancer, CTCAE and treatment. Title, abstract and then full-text screening was performed by two reviewers. Primary research studies and systematic review articles involving female adults in peer-reviewed articles or grey literature records, of any design or date and published in English, were included. Descriptive statistics and charting was used to summarize the results. Results: Of 1765 abstracts retrieved and screened, 37 articles were ultimately included for analysis. The majority of the studies involved Japanese patients (40.5%) followed by Chinese patients (24.3%) with an average of 468 patients being studied per study (ranging from 1-4,869 patients). Only a single study was conducted in the US. 35.1% of studies reported ethnicity and 64.8% of studies reported Asian ethnic subgroups. Most patients underwent whole-breast irradiation (62.1%). 37.5% of studies involved patients with TNM stages I-III breast cancer. Most patients were postoperatively enrolled after BCS (59.4%).ER/PR status was reported in most studies (54.1%) with an average of 553 patients being positive for either hormone receptor and averages of 210 and 905 patients each in studies where numbers were reported individually. HER-2 status was reported in 48.7% of studies with an average of 28 positive HER-2 patients in each study. Most studies reported skin toxicity following radiotherapy (81.1%), commonly grade 1 or 2 (40.5% each) affecting an average of 46% of patients in each study. These dermatological adverse events were radiation dermatitis, hyperpigmentation, fibrosis, hypertrophic scarring or erythema. Conclusions: Ethnicity was under-reported in the studied literature involving breast cancer treatment. Strategies to improve reporting of ethnic subgroups in literature and to reduce psychosocial barriers to access and treatment with a specific focus on mitigating dermatological adverse events of radiotherapy in Asian breast cancer patients may improve overall outcomes in this group.