Table 4. Factors Associated With Increased or Decreased RT Use by Age Group.

RT Use	Age 18-39 y (n = 1280)	Age 40-64 y (n = 3937)	Age ≥65 y (n = 3736)
Increased	Private insurance; deep depth of invasion; larger tumor	Private insurance; deep depth of invasion; larger tumor; urban living location; transition of care; stage II; positive surgical margins	Private insurance; deep depth of invasion; larger tumors; urban living location; transition of care; undifferentiated grade; clinical stage II tumor; positive surgical margins
Decreased	White Hispanic race/ethnicity; distance to reporting facility	White Hispanic race/ethnicity; distance to reporting facility	1 Comorbidity; lower limb tumor; distance to reporting facility

Abbreviation: RT, radiation therapy.