Patient characteristics
A total of 6107 COCA patients were obtained from the SEER database. Of these, 4276 were classified into the training cohort and 1831 in the validation group. Of the patients in the training cohort, 488 patients (11.4%) in the training cohort were < 50 years old, the majority (75.9%) were white, while the rest were black or other races, and 2154 (50.3%) were males. For the validation cohort, 916 patients (50%) were males, and 192 patients (48.0%) were < 50 years of age (Table The demographics and pathological characteristics of patients included in the present study