Why is pval.size ignored by ggsurvplot_facet?

Question

Why is pval.size ignored by ggsurvplot_facet()?

I am trying to change the size of the p-value text in my survival plot using ggsurvplot_facet(), but the call to pval.size appears to be ignored. If anyone can help me change p-value size in my survival plot it would be very much appreciated.

Reproducible example:

library(survival); library(survminer)

fit <- survfit( Surv(time, status) ~ sex, data = colon)

ggsurvplot_facet(fit, colon, facet.by = "rx", palette = "jco", pval = TRUE, pval.size = 20)

ggsurvplot_facet(fit, colon, facet.by = "rx", palette = "jco", pval = TRUE, pval.size = 1)

Answer 1

The simple answer is that pval.size is not a named parameter in this function, and the function doesn't do anything with it when you pass it in.

You would have to change the body of the function to achieve a change in the size of the pval label. Here's how to create a modified function that takes the p value size parameter:

ggsurvplot_facet2 <- function(pval.size = 5, ...)
{
  newcall <- bquote(
    p <- p + geom_text(data = pvals.df, aes(x = pval.x, y = pval.y, 
    label = pval.txt), size = .(pval.size), hjust = 0)
    )

    body(ggsurvplot_facet)[[20]][[3]][[8]] <- newcall
    ggsurvplot_facet(...)
}

So now you can do:

ggsurvplot_facet2(fit, colon, facet.by = "rx", palette = "jco", pval = TRUE, pval.size = 1)

Which gives this:

Then you can do

ggsurvplot_facet2(fit, colon, facet.by = "rx", palette = "jco", pval = TRUE, pval.size = 10)

Which gives this: