The CoxPH function is named for the Cox proportional hazards model, a statistical survival model. The function estimates coefficients by learning a set of explanatory variables. The output of the CoxPH function is input to the function CoxPredict and CoxSurvFit.
The CoxPH and CoxPredict functions do not support interaction terms (for example, using AGE*AGE as an item in the Cox proportional hazard model.