Background

Metastatic breast cancer (MBC) is an incurable disease in which latest therapies have evolving and improving patients survival. Inequities in the access to optimal treatment and shorter survival of BC by type of health care coverage were previously reported in an observational study in Brazil. In Brazil patients with private health coverage have access to the most recent therapies, however the public health system does not provide several therapies approved for the treatment of MBC such as everolimus, trastuzuman, eribulin, TDM-1, pertuzumab among others. The present analysis aims to analyze the impact of the type of health care coverage on survival outcomes of patients with MBC.

Methods

LACOG-0312 is a retrospective cohort study that enrolled patients with metastatic or locally advanced/recurrent unresectable BC diagnosed during 2012 in Brazil. Overall survival was defined as the time from the diagnosis of MBC and death from any cause. Comparisons were made using the Kaplan-Meier method based on the type of health care coverage (public vs. private). Cox regression analysis was performed for identification of independent prognostic factors associated with overall survival.

Results

A total of 634 patients with MBC were included in the study. Baseline characteristics by type of health care coverage was similar for visceral disease (43% in public and 44% in private, p=0.78), age at MBC diagnosis (median 62 years in public and 64 years in private, p=0.25), BC subtype (p=0.89), however more patients public insured were metastatic at diagnosis (42% vs. 33%) and had performance status >= 2 (12% vs. 3%).

The proportion of patients that received any first-line systemic therapy was similar in both groups (95.2% in public and 95.5% in private, p=1.0), however more patients with private insurance received second (82% vs. 71.6%, p=0.013) and third line (56% vs. 45%, p=0.024) therapy compared to public health covered patients.

OS from the date of MBC diagnosis in whole population was 36 months. There was no difference in terms of OS between private (42 months) and public (35 months) health insured patients (p=0.65). OS by BC subtype was 15 months for triple negative, 23 months in HER2 positive, 44 and 42 months for Luminal A and B respectively. There was no difference in OS by type of health insurance coverage in any BC subtypes.

In a multivariate analysis type of health care coverage did not associate with survival, only triple negative (HR (95% CI) – 3.495 (2.448 - 4.989); p <0.001), HER2 positive (HR (95% CI) - 2.287 (1.394 - 3.572); p = 0.001) BC subtypes and visceral metastases (HR (95% CI) – 1.413 (1.075 - 1.858); p <0.013) were correlated with a worse survival.

Conclusion

Our study suggestes that health care coverage is not associated with survival outcomes in patients with MBC. Potential differences in the access to optimal systemic treatments may not play a significant role in the survival of these patients. Real-world studies addressing the impact of new cancer therapies for different BC subtypes in MBC are needed.

Citation Format: Werutsky G, Zaffaroni F, Uema D, Cronenberger E, Cordeiro de Lima VC, de Sant'ana RO, Bines J, Santi PX, Goés RS, Liedke P, Batista MLM, Dybal V, Nerón YV, Beato CA, Borges G, Giacomazzi J, dos Santos LV, Ismael G, Rosa DD, Azambuja A, Andrade D, Martinez-Mesa J, Debiasi M, Barrios CH. Survival outcomes related to health care coverage in metastatic breast cancer in Brazil: A sub-analysis from the LACOG-0312 study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-10-17.