Is there any health and geographical disparity in indigenous and non-indigenous women of Western Australia (WA)? A retrospective review with respect to de novo metastasis.

Abstract

115 Background: Indigenous women with breast cancer have substantially higher mortality then non-Indigenous women. They are more likely to live in more remote communities with potential delays to presentation, investigation and diagnosis as well as slower access to cancer treatment facilities, potentially impacting survival. Here we explore by evaluating the diagnosis of de-novo metastasis and any association of remoteness, highlighting the geographic and possibly early access to treatment. Methods: A cohort of patients was retrospectively selected comprising age- and remoteness matched Indigenous and non-Indigenous women in a 1:1 ratio from the Western Australian Cancer Registry. Further data were collected from medical records and results systems. Remoteness was defined by the ARIA system. In addition, the distance from the nearest treatment center was calculated. The survival analysis was performed by Indigenous status and remoteness. Results: The final cohort comprised 250 Indigenous and 261 non–Indigenous women. Of the total, 7.6% (19/250) and 7.7% (20/261) were identified to have de-novo metastasis. At 10 years of follow up, most de-novo metastatic patients in both groups were from remote communities, distributed as 10.1, 9.1, 7.8, 8.7 and 5.0 % in metropolitan, inner regional, outer regional, remote and very remote areas respectively. In Indigenous group with de-novo metastasis the average distance of patient from treatment center was 1720km for vs 1018 km in Non-Indigenous patient with a p-value of 0.03. In non-metastasis cohort, Indigenous patient has 1065 km v 1241 km in non-indigenous group. Considering outcomes for those developing metastatic disease, median survivals after metastatic diagnosis were shorter for Indigenous patients, 21 v 33 months, p = 0.03. Conclusions: Indigenous women in WA with metastatic breast cancer have inferior survival outcomes from diagnosis of metastases relative to non-Indigenous peers. Most de-novo metastatic patients were from remote locations in both cohorts but no relation between remoteness and de-novo metastasis, identified to be impacting survival. Future studies are needed to better elucidate if any geographical, health care disparities and improve on treatment related outcomes. It is suggested to derive targeted policies to improve survival outcome of all Indigenous cancer patients, particularly those residing in remote areas.