This article was written by Dr Linda Dirven and first published in the 2016/17 edition of Brain Tumour, the IBTA's annual magazine that is distributed globally and free of charge in 113 countries and at international neuro-oncology and cancer conferences around the world. Read the full issue online and find out more here. Linda Dirven, PhD, is a senior researcher at Leiden University Medical Center, Leiden, The Netherlands.
What is health-related quality of life?
Although treatment with surgery, radiotherapy and/or chemotherapy does not yet result in cure, prolonged survival can be achieved in glioma patients. The incurable nature of this disease has resulted in health-related quality of life (HRQoL) becoming an important outcome measure in glioma research. Indeed, for glioma patients, palliation and the maintenance or improvement of HRQoL are considered at least as important as prolonged survival.
HRQoL refers to the impact of an individual’s health on the different dimensions of life, and may be altered by a medical condition or medical treatment. These different dimensions are reflected in HRQoL outcome measures, by including domains covering physical, cognitive, role, emotional and social functioning, as well as symptoms induced by the disease and its treatments.
HRQoL is a patient-reported outcome measure, meaning that it reflects the patient’s perspective, and is typically measured with self-report questionnaires. The most frequently used questionnaires in cancer research are the:
• European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30.
• Functional Assessment of Cancer Therapy (FACT) and the
• MD Anderson Symptom Inventory (MDASI)
These questionnaires cover general problems and symptoms that are related to cancer and its treatment (for example fatigue, nausea and vomiting, depression and bodily pain).
However, because brain tumour patients not only have cancer, but also a neurological disease, they have symptoms and problems that are different from other cancer patients; these include seizures, motor dysfunction, problems with memory and concentration, or changes in personality and behaviour. It is therefore necessary to supplement these generic HRQoL questionnaires with a brain tumour-specific module.
Value of HRQoL assessments in clinical trials and clinical practice
HRQoL assessments are important in both brain tumour clinical trials and in daily clinical practice.
In clinical trials, HRQoL assessments can be used to determine the so-called ‘net clinical benefit’. This means that the benefits of a new treatment strategy (e.g., longer survival duration) have to be carefully weighed against the negative effects of that treatment on the HRQoL.
Based on this information, the physician can decide whether the new treatment strategy is better than the standard treatment. Ideally, a new treatment strategy will result in prolonged survival without a negative impact on HRQoL. However, it is possible that a new treatment strategy results in a longer survival duration, but worse HRQoL. Or the other way around: a new treatment strategy results in a shorter survival duration, but improvement of HRQoL.
In these situations, it is difficult to decide what to opt for. And who should make the decision? A possible solution is if the physician and the patients make the decision together (i.e., ‘shared decision-making’) using the best available evidence, while taking into account the patient’s clinical and other characteristics (such as age, tumour type and location, and health status) as well as the patient’s preferences.
In daily clinical practice, HRQoL assessments can be used to monitor the patient’s functioning during the disease pathway. Regular assessment of HRQoL provides the physician with information on the impact of a specific treatment strategy in an individual patient. Intended and unintended adverse effects of the treatment can be monitored, and if these problems require follow-up, symptom treatment can be initiated or patients can be referred to another relevant health care professional. In addition, regular HRQoL assessments can increase the physician’s awareness of the patient’s functioning and well-being. This may subsequently improve the communication between the patient and the physician during follow-up consultations.
Problems in measuring and interpreting HRQoL
Although information on HRQoL is very valuable in brain tumour research, there may be some problems with the assessment of HRQoL that makes the interpretation of the results difficult.
A first challenge is caused by cognitive problems (problems in memory or concentration) that many brain tumour patients experience during the course of their disease. Patient ratings of their own HRQoL may therefore not always be an accurate reflection of their true functioning and symptom experience. Often patients feel that their HRQoL is good, while their family members disagree. A potential solution for this problem may therefore be to use ‘proxy ratings’, meaning that a family member or relative provides the information on the patients’ HRQoL.
Another problem with HRQoL assessment is missing data. Missing data can occur in two ways: missing a complete HRQoL questionnaire or missing one question within a questionnaire. Complete questionnaires can be missing when a patient misses a follow-up appointment with the physician. This is often due to the poor health status of the patient, progression of the disease, death of the patient, or when a patient no longer wishes to complete HRQoL questionnaires. One question within a questionnaire can be missing when a patient unintentionally misses a question or chooses not to answer a particular question for personal reasons.
A consequence of missing data is that HRQoL results about the effect of a specific treatment strategy may be inaccurate, leading to wrong conclusions.
Despite some difficulties in measuring and interpreting results, HRQoL continues to be an important outcome measure in brain tumour trials and clinical practice. Results of HRQoL assessments, whether measured in clinical trials or in clinical practice, do not only provide the physician with relevant information, but also the patient and his/her relatives.
HRQoL scores may improve the communication between the physician and patients and subsequently facilitate shared decision-making, which may ultimately result in better treatment choices for the patient. It is therefore important for all parties involved that patients continue to complete HRQoL questionnaires.