CSS within each stage, stratified by sex and age. Within each stage, females age <45 had superior CSS to same age group males and both females and males of other (older) age strata. (A) Stage II: Within age strata, female CSS was superior to males, but it reached statistical significance only for patients age <45 (p < 0.0001). (B) Stage III: Within age strata, the female CSS superiority was statistically significant for patients age <45 (p = 0.01) and ≥60 years (p = 0.004). (C) Stage IV: Within age strata, female CSS was superior to males, but it did not achieve statistical significance in subgroup analysis within age strata. CSS, cancer-specific survival.