Quality-of-Life Assessment in Pediatric Brain Tumor Patients and Survivors: Lessons Learned and Challenges to Face

Much has been written about the health-related quality of life (HRQOL) of adults with cancer based on a number of generic and cancer-specific instruments that have been applied with increasing sophistication in clinical studies and practice. Unfortunately, such work in pediatric cancer has lagged far behind. There are good reasons why the volume and quality of reporting of HRQOL outcomes in pediatrics has been slower to progress. Aside from the difficult conceptual and methodologic issues of determining the capacity of children to provide valid and reliable self-report based on age and threats to cognitive functioning, researchers in this area face additional struggles with regards to data collection, given small sample sizes and heterogeneity relative to tumor types, location, and treatment alternatives. In this issue, Bhat et al make an important foray into this area of research by providing us with a report on the use of the PedsQL 4.0 generic scale and cancer module in the pediatric brain tumor population at their center. Their experience raises for discussion many of the difficulties and challenges faced in this field. Although the focus of the article and this editorial is on the evaluation of HRQOL in the pediatric brain tumor population, the principles hold true for other pediatric populations. Researchers and clinicians alike must recognize that this is a time-consuming and iterative process. Articles such as that by Bhat et al represent important first steps but not the final answer. When selecting an HRQOL instrument for a study, a number of factors are considered, including relevancy to the target population, study outcome(s) of interest (eg, overall functioning, symptom relief, cognitive functioning, and so on), and practicality of instrument (eg, length of instrument; availability of language and age-appropriate versions; ease of administration, particularly in a busy, clinical setting). In addition, the instrument ideally should possess some demonstration of validity and reliability in the target population. The latter is often overlooked or insufficiently addressed. The use of the PedsQL in the pediatric brain tumor population has been limited, with previous studies including only a handful of children and adolescents on or off treatment for a brain tumor. This is despite years of psychometric testing in healthy children, children with various chronic medical conditions, and pediatric cancer survivors (which was one of the original populations in which earlier versions of this instrument was tested). Specifically, the original validation article on an earlier version of the PedsQL (PCQL-32) included nine pediatric brain tumor patients off treatment, and the most recent validation report of the current PedsQL generic core scales, fatigue scale, and cancer module included only 24 brain tumor patients on or off treatment. Another study using this instrument in pediatric cancer survivors reports an additional 23 pediatric brain tumor patients off treatment. Therefore, we applaud the efforts of Bhat et al in recruiting their study sample of 134 children and their parents. This is an important first step in the process of robustly characterizing HRQOL in this complex population. Specific demonstration of reliability and validity in this target population is particularly germane given the higher risk of cognitive impairment and developmental delay in this population, making self-report potentially more challenging. It is important to note that Bhat et al examined JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 23 NUMBER 24 AUGUST 2