TY - JOUR

T1 - Reconsideration of sample size and power calculation for overall survival in cancer clinical trials

AU - Jung, Inkyung

AU - Ko, Hee Jung

AU - Rha, Sun Young

AU - Nam, Chung Mo

N1 - Publisher Copyright:
© 2018 The Authors

PY - 2018/12

Y1 - 2018/12

N2 - When designing a cancer clinical trial, it is usual to assume an exponential distribution for a time-to-event outcome such as overall survival (OS). OS is often expressed as the sum of progression-free survival (PFS) and survival post-progression (SPP), each of which is assumed to be exponentially distributed. Then, OS does not follow an exponential distribution any more but a gamma or hypo-exponential distribution. In this study, we derived a sample size calculation formula for comparing OS between two treatment arms using the log-rank test for OS following a gamma or hypo-exponential distribution. We conducted a simulation study to evaluate the sample size and power calculation based on the gamma or hypo-exponential distribution. We found that we could reduce the sample sizes considerably compared to when assuming an exponential distribution for OS.

AB - When designing a cancer clinical trial, it is usual to assume an exponential distribution for a time-to-event outcome such as overall survival (OS). OS is often expressed as the sum of progression-free survival (PFS) and survival post-progression (SPP), each of which is assumed to be exponentially distributed. Then, OS does not follow an exponential distribution any more but a gamma or hypo-exponential distribution. In this study, we derived a sample size calculation formula for comparing OS between two treatment arms using the log-rank test for OS following a gamma or hypo-exponential distribution. We conducted a simulation study to evaluate the sample size and power calculation based on the gamma or hypo-exponential distribution. We found that we could reduce the sample sizes considerably compared to when assuming an exponential distribution for OS.

UR - http://www.scopus.com/inward/record.url?scp=85054253723&partnerID=8YFLogxK

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U2 - 10.1016/j.conctc.2018.09.007

DO - 10.1016/j.conctc.2018.09.007

M3 - Article

AN - SCOPUS:85054253723

SN - 2451-8654

VL - 12

SP - 90

EP - 91

JO - Contemporary Clinical Trials Communications

JF - Contemporary Clinical Trials Communications

ER -