Comparing colorectal cancer treatment and survival for Aboriginal and non-Aboriginal people in New South Wales.

Objectives: Our aim was to compare surgical treatment rates and survival rates for Aboriginal and non-Aboriginal people in New South Wales with colorectal cancer, and to describe the medical treatment received by a sample of Aboriginal people with colorectal cancer.

Design, Setting And Participants: All people diagnosed with colorectal cancer in NSW during 2001-2007 were identified and their cancer registry records linked to hospital admissions data and death records. A medical records audit of a sample of Aboriginal people diagnosed with colorectal cancer during 2000-2011 was also conducted.

Main Outcome Measures: Cause-specific survival, odds of surgical treatment, and the proportions of people receiving adjuvant treatments.

Results: Of 29 777 eligible colorectal cancer cases, 278 (0.9%) involved Aboriginal people. Similar proportions of Aboriginal (76%) and non-Aboriginal (79%) people had undergone surgical treatment. Colorectal cancer-specific survival was similar for Aboriginal and non-Aboriginal people up to 18 months after diagnosis, but 5 years post-diagnosis the risk of death for Aboriginal people who had had surgical treatment was 68% higher than for non-Aboriginal people (adjusted hazards ratio, 1.68; 95% CI, 1.32-2.09). Of 145 Aboriginal people with colorectal cancer identified by the medical records audit, 117 (81%) had undergone surgery, and 56 (48%) had also received adjuvant chemotherapy and/or radiotherapy.

Conclusions: Aboriginal people with colorectal cancer had poorer survival rates than non-Aboriginal people, although rates of surgical treatment, complications and follow-up colonoscopy were similar. More work is needed to identify and understand why outcomes for Aboriginal people with colorectal cancer are different from those of other New South Wales residents.