A new graphic for quality adjusted life years (Q-TWiST) survival analysis: the Q-TWiST plot.
One of the challenges of interpreting a Quality-adjusted time without symptoms of disease and toxicity (Q-TWiST) analysis is examining the sensitivity of conclusions that may be drawn to varying values of the utility coefficients for days with toxicity and days after disease progression. We present a graphic that parsimoniously displays the impact on median Q-TWiST survival across treatment groups of varying values of the utility coefficients. The goal of the graphic is to present a concise Q-TWiST analysis. We use Zhao and Tsiatis (Biometrika 1997; 84(2): 339-348) to adjust for the bias in Kaplan-Meier (K-M) estimates. The graphic contains bounds that approximate points for which statistical significance would be achieved by comparing the median Q-TWiST survival between treatment alternatives for each value of the utility coefficients. The plot may be generalized to compare Q-TWiST means, medians or percentiles across treatment groups. We demonstrate the application of the Q-TWiST plot through a re-analysis of a randomized phase III North Central Cancer Treatment Group (NCCTG) clinical trial of recombinant Interferon-2alpha in patients with malignant melanoma. We explore alternative options to customize the graphic representation for other data sets drawn from several NCCTG clinical trials.
Sloan
Jeff A
JA
Mayo Clinic and Mayo Foundation, Rochester, MN 55905, USA. jsloan@mayo.edu
Sargent
Daniel J
DJ
Lindman
Jed
J
Allmer
Cristine
C
Vargas-Chanes
Delfino
D
Creagan
Edward T
ET
Bonner
James A
JA
O'Connell
Michael J
MJ
Dalton
Robert J
RJ
Rowland
Kendrith M
KM
Brooks
Burke J
BJ
Laurie
John A
JA
D003196:Computer Graphics; D006801:Humans; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000627:therapeutic use; D008545:Melanoma / Q000188:drug therapy* / Q000401:mortality; D019057:Quality-Adjusted Life Years; D011994:Recombinant Proteins; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000401:mortality; D016019:Survival Analysis
D000077190:Interferon alpha-2; D016898:Interferon-alpha; D011994:Recombinant Proteins