An analysis of lines of treatment and survival analysis in older Indigenous and Nonindigenous women of Western Australia with breast cancer.

Abstract

e12529 Background: Indigenous women with breast cancer (BrCa) have markedly higher mortality and are more likely to be diagnosed with more advanced disease compared with non-indigenous women. However, it is unknown if Indigenous older adults receive same lines of treatment as non-indigenous older adults with breast cancer. Methods: We retrospectively examined data from WA cancer registry from 2001 to 2016 with BrCa by Indigenous status. Indigenous were considered older adults aged above 55 years and non-indigenous aged above 65 years. Cases with confirmed breast cancer, where chemotherapy was indicated in adjuvant and metastatic setting were included for analysis. Overall survival was compared between treatment arms of indigenous and non-indigenous cohort using log-rank analysis and demonstrated by Kaplan Meier curve. Chi-square was employed as well. Results: At time of writing, results were available for 75 indigenous and non-indigenous older adults identified for analysis from cohort of 315 older adults. 79% Indigenous received treatment in adjuvant setting, 14% was not offered and 7% declined adjuvant treatment compared to 89% non-indigenous patients received adjuvant chemotherapy, 7% were not offered and 4% declined therapy. In first line metastatic setting, only 65% older indigenous group received chemotherapy compared to 76% non-indigenous patients. In second line, only 48% patients received treatment compared to 61% non-indigenous patients. In third line, 23% indigenous women received chemotherapy compared to 51% non-indigenous women with significant p-value 0.012. The rate of decline was higher in indigenous cohort. Kaplan meier curve of 10-year survival analysis favors the Non-Indigenous group. The difference between groups was 55 vs 68%. When comparing groups, the median survival of Indigenous group was 79 months and mean survival of Non-Indigenous cohort was 97 months. Log-rank testing p value 0.0025. Conclusions: In this study, indigenous patients have shown reduced survival outcomes and with drop in lines of treatment in the course of disease, highlighting a potential area to address and improve survival outcomes, along with addressing barriers that lead to treatment disparity in older adults.