title: R: KM curves plot in survival package change x axis range
body: <p>I'm using the survival package to generate the KM curves for two populations but when I tried to define the xmax parameter, I am unable to extend the x-axis range from 0-15 to 0 - 50.</p>
  
  <p>Here is my code:</p>
  
  <pre><code> library(sm)
  library(survival)
  comb = read.csv("S:/Novocure/ChemoSKTime2Resp.csv", head = TRUE)
  comb
  survobj = with(comb, Surv(SK.response.time,Censored))
  survobj
  
  # Compare the survival distributions of nonresponders(0) and responders(1)
  
  fitresp = survfit(survobj ~ response, data=comb)
  fitresp
  summary(fitresp)
  
  # plot the survival distributions by response
  
  plot(fitresp, xlab="Tumor Progression Time in Months", 
    ylab="% Progressed", yscale=100, col=c("red","blue"),
    main="Chemo Time to Tumor Progression Distribution", xmax = 50) 
    legend("topright", title="Chi-sq = 5.2, P = 0.0222", 
    c("Non-responders", "Responders"), fill=c("red", "blue"))
  </code></pre>