How can I add specific value on x-axis in ggsurvpl

Question

I want 56 to show on the x-axis, but I can't figure it out.

I have the following script. I have tried to add the following to the script xlim = c(seq(0,100, by=10),56) but that does not seem to work.

I have tried to google it and I have read on R-documentation. I hope you can help.

library(survival)
library(survminer)
library(ggplot2)
fit <- survfit(Surv(p$time.recur.months, p$recurrence) ~ p$simpson.grade, 
               conf.type="log", data=p)

j <- ggsurvplot(
  fit,                     
  data = p, 
  fun="cumhaz",
  risk.table = TRUE,       
  pval = TRUE,      
  pval.coord = c(0, 0.25),
  conf.int = F,         
  legend.labs=c("Simpson Grade 1" ,"Simpson Grade 2", "Simpson Grade 3", 
                "Simpson Grade 4"),
  size=c(0.7,0.7,0.7,0.7),                    
  xlim = c(0,100),
  alpha=c(0.7),
  break.time.by = 10,    
  xlab="Time in months",
  #ylab="Survival probability",
  ggtheme = theme_gray(),             
  risk.table.y.text.col = T,
  risk.table.y.text = TRUE,           
  ylim=c(0,0.5),
  cumevents=T,
  palette="Set1"       
)

# My Data
p <- structure(list(recurrence = c(0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 
0L, 0L, 1L, 0L, 0L, 0L, 1L, 1L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 
0L, 0L, 1L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 
0L, 0L, 0L, 0L, 1L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 
1L, 1L, 0L, 0L, 1L, 1L, 0L, 0L, 0L, 0L, NA, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 1L, 0L, 1L, 0L, 0L, 0L, 1L, 1L, 1L, 1L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 1L, 0L, 0L, 
0L, 0L, 0L, 1L, 0L, 1L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 1L, 
0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L), time.recur.months = c(NA, NA, 
NA, NA, NA, NA, 92L, NA, NA, NA, 74L, NA, NA, NA, 2L, 8L, NA, 
NA, NA, NA, 58L, NA, NA, NA, NA, NA, 3L, NA, 4L, NA, NA, NA, 
NA, NA, NA, NA, NA, NA, NA, 39L, NA, NA, NA, NA, 15L, NA, NA, 
NA, NA, NA, NA, NA, NA, NA, NA, 12L, 56L, 57L, NA, NA, 49L, 17L, 
NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 5L, 
NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 9L, NA, 
89L, NA, NA, NA, 8L, 6L, 8L, 4L, NA, NA, NA, NA, NA, NA, NA, 
NA, NA, NA, NA, NA, 60L, NA, NA, 38L, NA, NA, NA, NA, NA, 90L, 
NA, 58L, 54L, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 
NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 
NA, NA, NA, NA, NA, NA, NA, NA, NA, 53L, NA, NA, 124L, NA, NA, 
NA, NA, NA, NA, 7L, NA), simpson.grade = c(3L, 1L, 1L, 2L, 4L, 
1L, 1L, 1L, 2L, 1L, 4L, 1L, 1L, 2L, 1L, 2L, 1L, 4L, 2L, 3L, 2L, 
1L, 1L, 1L, 1L, 1L, 3L, 1L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 1L, 
1L, 2L, 1L, 1L, 3L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 1L, 
1L, 1L, 4L, 3L, 1L, 1L, 4L, 1L, 3L, 1L, 1L, 1L, 1L, 1L, 3L, 1L, 
3L, 4L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 4L, 1L, 1L, 1L, 4L, 1L, 1L, 
1L, 2L, 1L, 2L, 4L, 4L, 1L, 4L, 4L, 1L, 2L, 1L, 1L, 4L, 4L, 4L, 
4L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 4L, 1L, 2L, 1L, 4L, 1L, 1L, 4L, 
4L, 1L, 3L, 1L, 1L, 1L, 3L, 2L, 4L, 4L, 1L, 4L, 4L, 4L, 4L, 1L, 
1L, 1L, 1L, 4L, 1L, 4L, 4L, 1L, 4L, 4L, 1L, 4L, 4L, 3L, 1L, 1L, 
1L, 4L, 1L, 1L, 1L, 1L, 3L, 1L, 1L, 2L, 2L, 2L, 4L, 1L, 4L, 2L, 
1L, 1L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 3L, 1L)), .Names = c("recurrence", 
"time.recur.months", "simpson.grade"), class = "data.frame", row.names 
= c(NA, 
-176L))

Answer 1

j is a ggsurvplot object, which is in turn a list of other objects. You can change the ggplot object at j$plot. The following will add 56 to the x-axis labels:

j$plot <- j$plot + 
  scale_x_continuous(breaks = sort(c(seq(0, 100, 10), 56)))

j

Personally I don't think it's a good look, as I expect evenly spaced breaks along the x-axis to match the tables below. If you want to draw attention to the position 56, I would suggest a vertical line and/or annotated label instead:

j$plot <- j$plot +
  geom_vline(xintercept = 56, linetype = "dashed") +
  annotate("text", x = 56, y = 0, label = "56", hjust = -0.5)

j