[Health-related quality of life in phase III cancer clinical trials: from questionnaire administration to statistical analysis]

Endpoints refer to clinical and biological measurements that assess efficacy of therapeutic strategies. As the American Society of Clinical Oncology states, active treatment in cancer is generally undertaken with the goal of providing improved quantity and/or quality of patient survival. Health-related quality of life (HRQoL) reflects the patient-perceived evaluation of one's health, including physical, emotional, and social dimensions as well as symptoms due to disease or treatment. HRQoL is recognized as a component endpoint for cancer therapy approvals by the American Society of Clinical Oncology and the FDA. Many self-completion HRQoL questionnaires have been developed and validated. Two main statistical methods have been developed to longitudinally analyze HRQoL. The first is the linear mixed model for repeated measure (LMM). The second is a survival approach, which estimates the time to HRQoL deterioration. However, there is no guideline for methods of analyzing and reporting longitudinal changes in HRQoL scores. Moreover, HRQoL could also be combined with other endpoints like progression-free survival as co-primary endpoint, but the use of co-primary endpoints in cancer clinical trials is a new approach and methodological researches must be pursued to promote such designs.