Abstract P6-11-14: Poor overall survival in women with de novo metastatic breast cancer: Does this reflect a lack of access to healthcare?
Authors: Soares Leonardo Ribeiro , Freitas-Junior Ruffo , Martins Edesio , Oliveira Jose C , Curado Maria P 
Published: March 2020

Introduction: Due to its epidemiological and therapeutic aspects, metastatic breast cancer (MBC) is a highly relevant clinical condition. Currently, most of the data on MBC originate from retrospective, hospital-based studies or controlled trials involving specific populations and treatments. On the other hand, population-based studies have the advantage of enabling an epidemiological analysis to be made of different populations, which may help in the development of specific public policies. This study aimed to estimate overall survival in women diagnosed with de novo MBC in the city of Goiânia, Brazil.

Methods: Cases were identified at the Goiânia population-based cancer registry between 1995 and 2011. All women with metastatic disease at diagnosis were included in the study. The clinical and demographic characteristics of the sample and data related to the diagnosis and treatment of the disease were collected. Variables not recorded systematically in the cancer registry were collected directly from medical records. The distribution of survival was calculated using the Kaplan-Meier estimator and compared between the groups using the log-rank test, with 95% confidence intervals. Cox regression analysis was used for the multivariate analysis, with the variables being adjusted according to hormone receptor expression. P-values &lt; 0.05 were considered statistically significant.

Results: Over the 16-year period covered by the study, 5,289 cases of breast cancer occurred in residents of Goiânia, Brazil. Of these, 277 women (5.2%) had MBC. Mean age at diagnosis was 54.7 (±14.5) years. Overall survival at 60 and 120 months was 19.9% and 7.7%, respectively. In the group of patients with hormone receptor-positive cancer, endocrine therapy was prescribed in 14.0% of cases (6/43) as first-line treatment for MBC and in 48.5% (17/35) as second-line treatment. Of the 23 women with HER2-positive breast cancer for whom data were available on the treatment received, three had received trastuzumab as first-line treatment and two as second-line treatment. In the univariate analysis of 5-year overall survival, the following factors were found to be statistically significant: staging (T) (p=0.01); histological type (p=0.02), histological grade (p=0.03), estrogen receptor status (p=0.02), progesterone receptor status (p&lt;0.001), tumor phenotype (p=0.02), type of healthcare (p=0.04), whether breast surgery had been performed (p&lt;0.001) and the initial site of metastases (p=0.02). In the group of patients with hormone receptor-positive tumors, there was no difference in survival as a function of the type of first-line treatment received (chemotherapy versus endocrine therapy). In the 5-year multivariate analysis adjusted for hormone receptor status, the type of healthcare (p=0.01) and whether breast surgery was performed (p=0.03) remained statistically significant.

Conclusion: This is the first population-based study dealing with MBC in Brazil. Overall survival was low in this population, and lower than rates found in specialist centers in Brazil and in developed countries. Increasing access to diagnosis and treatment could increase the likelihood of survival in patients with MBC treated in the public healthcare system.

Table 1. Overall survival in women with de novo metastatic breast cancer in the city of Goiânia, Brazil, by the type of healthcare (1995-2011).Health carePublicPrivateTotal*5-year survival (%)6.922.4128*Survival (months)19.727.221.9Events81 (90.0)28 (73.3)109 (85.2)

Citation Format: Leonardo Ribeiro Soares, Ruffo Freitas-Junior, Edesio Martins, Jose C Oliveira, Maria P Curado. Poor overall survival in women with de novo metastatic breast cancer: Does this reflect a lack of access to healthcare? [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-11-14.