I have censored survival data. I have been using a log rank test to get a p-value for overall survival. For example in R I have been using the survdiff function from the survival package and the below chisq test to find a survival pvalue. However this gives you the 2 tail test p value. I am only interested in one direction, For example do the patients with some mutation have better survival. My hypothesis is such that I am not interested in the other direction. Chisq being a goodness of fit measure captures both directions. What would be the equivalent code or reasoning to capture the one way or one tail logrank p value?
input<-as.formula(paste0("Surv(survival_time,censoring_status) ~ ",gene_name)) gene.survival <-survdiff(input,data=data) p.val <- 1 - pchisq(gene.survival$chisq, length(gene.survival$n) - 1)
one-way one way one-tailed one tail log-rank