Cancer treatment and the risk of cancer death among Aboriginal and non-Aboriginal South Australians: analysis of a matched cohort study

Abstract

BackgroundAboriginal and Torres Strait Islander Australians have poorer cancer outcomes than other Australians. Comparatively little is known of the type and amount of cancer treatment provided to Aboriginal and Torres Strait Islander people and the consequences for cancer survival. This study quantifies the influence of surgical, systemic and radiotherapy treatment on risk of cancer death among matched cohorts of cancer cases and, the comparative exposure of cohorts to these treatments.MethodsCancers registered among Aboriginal South Australians in 1990–2010 (N = 777) were matched with randomly selected non-Indigenous cases by sex, birth and diagnostic year, and primary site, then linked to administrative cancer treatment for the period from 2 months before to 13 months after diagnosis. Competing risk regression summarised associations of Indigenous status, geographic remoteness, comorbidities, cancer stage and treatment exposure with risk of cancer death.ResultsFewer Aboriginal cases had localised disease at diagnosis (37.2% versus 50.2%) and they were less likely to: experience hospitalisation with cancer diagnosis, unadjusted odds ratio (UOR) = 0.76; 95%CI = 0.59–0.98; have surgery UOR = 0.65; 95%CI = 0.53–0.80; systemic therapies UOR = 0.64; 95%CI = 0.52–0.78; or radiotherapy, UOR = 0.76; 95%CI = 0.63–0.94. Localised disease carried lower risk of cancer death compared to advanced cases receiving surgery or systemic therapies, SHR = 0.34; 95%CI = 0.25–0.47 and SHR = 0.35; 95%CI = 0.25–0.48. Advanced disease and no treatment carried higher risk of cancer death, SHR = 1.82; 95%CI = 1.26–2.63.ConclusionThe effects of treatment did not differ between Aboriginal and non-Indigenous cohorts. However, comparatively less exposure to surgical and systemic treatments among Aboriginal cancer cases further complicated the disadvantages associated with geographic remoteness, advanced stage of disease and co-morbid conditions at diagnosis and add to disparities in cancer death. System level responses to improving access, utilisation and quality of effective treatments are needed to improve survival after cancer diagnosis.

Population-based utility scores for HPV infection and oropharyngeal squamous cell carcinoma among Indigenous Australians

“…It is interesting that Indigenous women in our study had higher utility scores for the ‘early stage invasive throat cancer’ health state at both 12-months and lifetime duration than Indigenous men. This finding is consistent with research by Banham and colleagues on Indigenous South Australians’ cancer treatment [ 34 ], who reported that Indigenous females received more treatment, such as surgeries, systemic therapy and radiotherapy than males, on average. The authors concluded that this was consistent with health-related gender differences observed in the wider Australian population [ 32 ].…”

Young-Onset Gastrointestinal Adenocarcinoma Incidence and Survival Trends in the Northern Territory, Australia, with Emphasis on Indigenous Peoples

“…These outcomes concur in part with research by Condon et al [ 17 ], who also demonstrated poorer cancer survival amongst Indigenous peoples in the NT, with diagnoses at an advanced stage of the cancer being a contributing factor. Additionally, a previous study from South Australia has flagged issues around availability and access to surgical and systemic treatments amongst Aboriginal cancer patients compared to non-Aboriginal South Australian patients, which further complicated the disadvantages associated with geographic remoteness and advanced stage of disease at diagnosis, compounded by the presence of associated comorbid conditions [ 49 ]. In the present study, owing to the lack of stage-specific data, we are unable to comment on whether a delayed diagnosis was responsible for the poorer survival observed.…”

Indigenous Australians’ Experiences of Cancer Care: A Narrative Literature Review

“…Research evidence notes a range of barriers to delivering the best possible quality cancer care to Indigenous people. Barriers include navigating complex cancer treatment and management pathways (often associated with late diagnosis and multiple comorbidities) [ 8 , 9 ], inadequate provision of long-term and continuous care to survivors [ 10 ], and patients’ distrust of the healthcare system [ 11 ]. Delivery of health services in rural/remote areas is another barrier due to the lack of access to services (such as specialist care) and the workforce shortage compared to services available in urban or larger regional cities [ 12 ].…”