The Paradoxical Protective Effect of Immigration on Colorectal Cancer Survivals

It is unknown whether the place of birth would affect colon cancer survival.

An observational study of colon cancer patient data using the SEER database from 1973 to 2010 was performed. Patients with more than one primary cancer in their lifetime or patients who were under age 18 were excluded. The primary outcome was cancer-specific survival. Cox proportional hazards analyses were performed, adjusting for patient demographics and oncological characteristics.

A total of 262,618 colon cancer patients were analyzed, with the majority (86.0%) born in the US. The overall 5-year cancer-specific survival rate was 51.4% and was significantly lower for US-born than non-US born patients (50.4% vs 58.1%). This difference persisted in local/regional disease and in cases with distant metastasis, and across racial groups. On adjusted analysis, US-born patients had worse disease-specific survivals (HR 1.28, 95% CI 1.24-1.33), and this effect persisted in all racial groups except in Asians.

US-born patients have worse survivals than non-US born patients. This is paradoxical given known disparities in quality of care delivered to immigrant populations. It may be useful to consider including geographical histories in patient interviews.