INTRODUCTION
CRC, cancer, NCIC, Colorectal cancer, Cancer
CANCER, COLORECTAL CANCER, CANCER
Colorectal cancer (CRC) is the third most commonly diagnosed cancer, and the third deadliest cancer worldwide.The QoL questionnaire designed by the European Organization for Research and Treatment of Cancer (EORTC‐QLQ‐C30) is frequently used in a variety of cancer patient populations.The majority of studies on the relationship between health‐related QoL and survival of CRC patients evaluated QoL at a single time‐point, such as trial entry, or time of diagnosis; there is a lack of studies assessing the association between longitudinal QoL and survival.We are working on a randomized clinical trial CO.20. This trial was conducted by the National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) and the Australasian Gastrointestinal Trials Group (AGITG). The CO.20 Phase III trial randomized 750 chemotherapy‐refractory metastatic CRC patients to receive Brivanib+Cetuximab (To study QoL trajectories, a longitudinal method of evaluating QoL of clustered patients was necessary. A longitudinal study has the advantage over single time‐point data for studying the change patterns of measurements over time. Growth mixture models (GMM) can deal effectively with such time‐related longitudinal data.