Hypofractionated Radiotherapy for Breast Cancer: Findings From an International ESTRO-GIRO Survey

Abstract

Hypofractionated radiotherapy (HF) for early breast cancer has been found to be equivalent to conventional fractionation (CF) in several large studies. More recently, accelerated HF regimens and HF in more advanced disease has been evaluated and adopted. Using data from the European Society of Radiation Oncology' (ESTRO) Global Impact of Radiotherapy in Oncology (GIRO) initiative survey on HF, this study aims to identify patterns, facilitators and barriers to uptake of breast cancer HF across World Bank income groups.The ESTRO-GIRO initiative administered an anonymous, electronic survey to radiation oncologists from January 2018 to January 2019. Details on physician demographics, clinical practice, preferred HF regimen for specific breast cancer clinical scenarios (curative and palliative), and justifications for HF practices were collected. Curative scenarios included: node-negative (N0) following breast-conserving surgery (BCS) and mastectomy, and node-positive (N+) following BCS and mastectomy. Palliative scenarios evaluated HF for symptom control. Factors associated with HF were assessed using multivariate logistic regression models.A total of 1,434 physicians responded to the breast survey scenarios, with 1251 (87%) from high-income (HICs) and upper middle-income countries (UMICs) and 183 (13%) from lower middle-income countries (LMICs). The most common HF fraction size was between 2.5 and 2.9 Gy delivered in a total of 15 fractions for curative indications (30%); only 1% of respondents reported using a 5-fraction regimen. For palliative indications, the most common HF fraction size was between 3 Gy and 3.5 Gy in 10 fractions (23%). In N0 disease following BCS, there was no significant difference in use of hypofractionation in LMICs compared to HICs and UMICs. Respondents in Africa were less likely to hypo fractionate compared to Europe (OR = 0.29 (0.12,0.69), P = 0.006) and those using Cobalt-60 were less likely to hypo fractionate (OR = 0.55 (0.37,0.84), P = 0.005). In the other curative scenarios, those in LMICs were more than twice as likely to hypo fractionate compared to those in HICs and UMICs. There were no differences in use of HF across income groups for palliative symptom control. Published evidence was the most cited justification for HF (89%) across income groups. Lack of advanced technology was cited as a barrier by 14% in LMICs, compared to 5% in HICs and UMICs.Patterns of HF for breast cancer varied across income groups for curative indications, with minimal uptake of accelerated regimens. Targeted interventions are needed to address barriers to HF and support evidence-based utilization.