Changing y axis rotation - changing theme elements of ggsurvplot

Question

I am making a survival curve using R in R studio. I am trying to rotate the title of my y axis to be horizontal, using guidance from previous posts, and I keep receiving an error message. I am using the following code:

my_survplot_c = ggsurvplot(my_survfit_c, data = cohort_comb,                 
           risk.table = TRUE,
           ggtheme = theme_bw(),
           palette = "Dark2",
           conf.int = FALSE,
           pval=FALSE,
           legend.title = "OTC Offered", legend.labs = c("No", "Yes"),
           ylab = "Proportion without POI", xlab = "Time (years)")

my_survplot_c + ylab("Proportion\nwithout POI") + theme(axis.title.y = element_text(angle=0))

my_survplot_c

The error message I am receiving is: Error in my_survplot_c + ylab("Number of\nSolutions") + theme(axis.title.y = element_text(angle = 0)) : non-numeric argument to binary operator

I suspect the solution is simple but I am new to R and would appreciate any advice! Thank you.

Answer 1

You could first transform your plot as a ggplot object and your last argument will work :

my_survplot_c = ggsurvplot(my_survfit_c, data = cohort_comb,                 
           risk.table = TRUE,
           ggtheme = theme_bw(),
           palette = "Dark2",
           conf.int = FALSE,
           pval=FALSE,
           legend.title = "OTC Offered", legend.labs = c("No", "Yes"),
           ylab = "Proportion without POI", xlab = "Time (years)")$plot

my_survplot_c + ylab("Proportion\nwithout POI") + theme(axis.title.y = element_text(angle=0))

my_survplot_c