ESTRO 2022 - Abstract Book

S1039

Abstract book

ESTRO 2022

Conclusion High locoregional control could be achieved with multidisciplinary management of non-metastatic IBC, suggesting the anti- tumor efficacy of radiotherapy in this rare but pejorative clinicopathological presentation. While comparing favorably with historical cohorts, OS and DFS could be potentially improved in the future with the use of new systemic treatments, such as PARP-inhibitors or immunotherapy.

PO-1230 Delay in postoperative radiation in pts with breast cancer in Brazil: a sub-analysis of AMAZONA III

J. Prestes 1 , D. Rosa 2 , C. Barrios 3 , J. Bines 4 , G. Werutsky 3 , E. Cronemberger 5 , G. Queiroz 6 , S. Simon 7 , T. Rebelatto 8 , R. de Jesus 3 , M. da Silva 9 , G. Marta 10 1 Hospital Sírio Libanês , Clinical Oncology, São Paulo, Brazil; 2 Hospital Moinhos de Vento (HMV)/ Latin American Cooperative Oncology Group, Clinical Oncology, Porto Alegre, Brazil; 3 Latin American Cooperative Oncology Group, Clinical Oncology, Porto Alegre, Brazil; 4 Latin American Cooperative Oncology Group/ Instituto Nacional de Câncer (INCA), Clinical Oncology, Rio de Janeiro, Brazil; 5 Latin American Cooperative Oncology Group/ Centro Regional Integrado de Oncologia, Clinical Oncology, Porto Alegre/ Fortaleza, Brazil; 6 Latin American Cooperative Oncology Group/ Hospital Araújo Jorge, Clinical Oncology, Porto Alegre/ Goiânia, Brazil; 7 Latin American Cooperative Oncology Group/ Centro Paulista de Oncologia, Clinical Oncology, Porto Alegre/ São Paulo, Brazil; 8 Latin American Oncology Group, Clinical Oncology, Porto Alegre, Brazil; 9 Latin American Cooperative Oncology Group/ Hospital Universitário de Santa Maria, Clinical Oncology, Porto Alegre/ Santa Maria, Brazil; 10 Hospital Sírio Libanês/ Latin American Cooperative Oncology Group, Radiation Oncology, São Paulo/ Porto Alegre, Brazil Purpose or Objective The delay to start postoperative radiation therapy (PORT) after neoadjuvant chemotherapy and surgery may be associated with poorer clinical outcomes, increasing tumor recurrence and reduced overall survival rates. This analysis aimed to assess the factors influencing the delay to start PORT. Materials and Methods The AMAZONA III is an observational multicentric prospective Brazilian cohort study conducted from January 2016 to March 2018. BC patients submitted to neoadjuvant chemotherapy followed by surgery and PORT were classified into two groups regarding time to initiation of PORT: ≤ 8 weeks and > 8 weeks (delay group). The association between delayed PORT and the following factors was evaluated: age, race, parity, employment status, marriage status, education level, type of health insurance, monthly household income, clinical stage (CS), and surgery type. Univariable and multivariable regressions were performed. Backward selection was used to determine the final multivariable model. Results In 582 patients evaluated, median age was 49 years. Most patients (58.9%) had CS III, were treated in the public health system (74.1%) and had monthly household income of 1-3 minimum wages (45.9%). 43.1% of patients had low educational level (primary school or less). 29 patients had missing data and were not included in the timelines analysis. PORT was started ≤ 8 weeks in 446 (80.7%) patients and > 8 weeks in 107 (19.3%). Patients with low educational level (1.55; 95%CI 1.08 - 2.22; p=0.0173), public health insurance (3.26; 95%CI 1.75 - 6.08; p ≤ 0.0001), and Luminal A/LuminalB-HER- 2negative subtype (1.87; 95%CI 1.11 - 3.17; p=0.0245) were at high risk of delaying PORT; while those who did not receive adjuvant endocrine therapy (0.67; 95%CI 0.45 - 0.98; p=0.0312) were at low risk of delaying PORT. Public health insurance was the only independent factor associated with delay in PORT (2.96; 95%CI 1.59 - 5.50; p=<0.0001) – Table 1.

Table 1 – Uni and multivariable analysis for PORT delay.

Conclusion