Racial/ethnic disparities in the adjuvant chemotherapy of locally advanced colon cancer patients.

BACKGROUND

Most race/ethnicity-oriented investigations focus on Caucasian Americans (whites) and African Americans (blacks), leaving Asians, Hispanic white (Hispanics), and other minorities less well studied. Adjuvant chemotherapy (CT) after curative resection is critical to patients with locally advanced colon cancer (LACC). We studied the racial disparities in the adjuvant CT of LACC to aid in selecting optimal treatments for people from different races/ethnicities in this era of precision medicine.

METHODS

Patients with American Joint Committee on Cancer (AJCC) stage II or III colon cancer (CC) (together termed as LACC) were included based on Surveillance, Epidemiology, and End Results cancer registry-Medicare linked databases. The log-rank test and Cox multivariate regression analysis were performed to investigate the racial/ethnic disparities in cohorts divided according to the regimen of adjuvant CT.

RESULTS

In the LACC patients who did not receive adjuvant CT, Asian patients had better survival than other groups (all, P <0.05). For the fluoropyrimidine cohort, the survival of Asian patients was better than that of whites, blacks, and other minorities (all, P <0.05). For the fluoropyrimidine with oxaliplatin cohort, other minorities had superior survival to other groups (all, P <0.05). Similar findings were demonstrated for patients with AJCC stage II and III CC, and the observed better survival persisted after adjustments in the Cox models.

CONCLUSIONS

Among LACC patients not receiving adjuvant CT, Asians achieved better survival than other races/ethnicities. Superior survival was also observed for Asians in the fluoropyrimidine cohort and for other minorities in the fluoropyrimidine with oxaliplatin cohort for AJCC stage III CC.