CanSUR is the statistical tools developed by R especially to use in cancer research.
gen2stage (Generalized two-stage designs for phase II single-arm studies)
ss2stagePSO (Sample size determination for phase II single-arm adaptive 2-stage deisgn)
ssLogitNorm (Power and sample size determination on a logit-normal distribution)
If you have any question, please contact via the email: biostatistician dot kim at gmail dot com.