International Region of Birth and Long-Term Outcomes for Patients Undergoing Colorectal Cancer Resection in an Australian Population.

Background: Overseas birth is associated with a survival advantage in colorectal cancer in Australia. We wished to analyse this survival based on global region of birth, controlling for cancer-specific and other causes of death.

Methods: A database of resected colorectal cancers from 2010 to 2016 (n = 1596) was grouped according to patient global region of birth. Chi-squared testing was used to compare factors including patient demographics and AJCC stage. Kaplan-Meier and competing-risk analysis were used to compare 5-year survival outcomes between patients born in different regions, and regression analysis was used to control for age.

Results: 751 (47.1%) patients were born overseas. 385 (24.1%) originated from Europe, 124 (7.8%) from East and SE Asia, 92 (5.8%) from the Middle East, and the remainder from other global regions. Immigrants from East or SE Asia were more likely to present with node-positive disease (p = 0.048) than those born in Australia. Immigrants from East and SE Asia and the Middle East had significantly better all-cause 5-year survival than patients born in Australia (73.4% and 80.4% vs. 60.4%, p < 0.0001). Immigrants from the Middle East retained their cancer-specific survival advantage after competing risk analysis (HR 0.76, p = 0.027). Immigrants from Europe displayed no significant difference in all-cause or disease-specific survival compared to individuals born in Australia.

Conclusion: Patients born in the Middle East appear to have a colorectal cancer-specific survival advantage compared to those born in Australia, unrelated to stage at presentation. This has significant implications for prognosis and future research directions.