ESTRO 2022

Session Item

Breast

Session Code: 6006

Session Type: Poster (digital)

Track: Clinical

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

Gustavo Marta , Brazil

Presentation Number: PO-1230

Abstract

Abstract Title:

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

Authors:

Julio Prestes¹, Daniela Rosa², Carlos Barrios³, José Bines⁴, Gustavo Werutsky³, Eduardo Cronemberger⁵, Geraldo Queiroz⁶, Sérgio Simon⁷, Taiane Rebelatto⁸, Rafaela de Jesus³, Maurício da Silva⁹, Gustavo Marta¹⁰

¹Hospital Sírio Libanês , Clinical Oncology, São Paulo, Brazil; ²Hospital Moinhos de Vento (HMV)/ Latin American Cooperative Oncology Group, Clinical Oncology, Porto Alegre, Brazil; ³Latin American Cooperative Oncology Group, Clinical Oncology, Porto Alegre, Brazil; ⁴Latin American Cooperative Oncology Group/ Instituto Nacional de Câncer (INCA), Clinical Oncology, Rio de Janeiro, Brazil; ⁵Latin American Cooperative Oncology Group/ Centro Regional Integrado de Oncologia, Clinical Oncology, Porto Alegre/ Fortaleza, Brazil; ⁶Latin American Cooperative Oncology Group/ Hospital Araújo Jorge, Clinical Oncology, Porto Alegre/ Goiânia, Brazil; ⁷Latin American Cooperative Oncology Group/ Centro Paulista de Oncologia, Clinical Oncology, Porto Alegre/ São Paulo, Brazil; ⁸Latin American Oncology Group, Clinical Oncology, Porto Alegre, Brazil; ⁹Latin American Cooperative Oncology Group/ Hospital Universitário de Santa Maria, Clinical Oncology, Porto Alegre/ Santa Maria, Brazil; ¹⁰Hospital Sírio Libanês/ Latin American Cooperative Oncology Group, Radiation Oncology, São Paulo/ Porto Alegre, Brazil

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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.

Material 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

The majority of BC patients in Brazil initiate PORT at adequate timeline. However, patients from the public health system have a significantly higher risk of delayed PORT and thus strategies to facilitate and streamline the access to PORT must be implemented.