Use of tnm as continuous variable in univariate or multivariate analysis


I hope I put this post in the correct group.

May I use TNM stage (1,2,3....), N stage (0,1,2,3.....) or grade (1,2,3,4....) as continuous variable when performing logistic regression or cox regression for survival?

For example can I say that T stage (It was not trasformed it in a categorical variable (HR 3.2 CI 95% 2.3-10.1, p=0.001) is a predictor of poor survival?

If it is allowed do I have any advantages/disadvantages in doing that?

Thank you very much for your help in advance.
Yes, you can. But you can be better off by using dummy variables for all categories of TNM except for the reference category. Ultimately, a model selection criterion (like cross-validation or AIC) will tell you which model is better.
Thank you very much.

I do not understand why most people in their paper convert T or N to categorical variables.....

I will study those modell then.