3.1 Introduction
A diagnosis of cancer is usually associated with debilitating treatment and premature death. However, due to medical advancements, increasing numbers of patients are surviving treatment and many remain free from cancer for the rest of their lives. Consideration of quality-of-life issues for these patients is a fundamental part of helping people through their experience of diagnosis, treatment and surviving cancer or living as well as they possibly can until the moment they die. This chapter reviews the concept of quality of life from an individual and health related perspective and as a measure of outcome in cancer studies. Issues related to assessing and measuring quality of life are discussed in terms of how effective questionnaires and visual analogue scales are at providing balanced and meaningful data.
3.2 Quality of Life
The concept of quality of life is complex, dynamic and subjective, therefore, it is difficult to attribute a single definition. Studies generally describe it as multidimensional, comprising individuals’ perceived physical, psychosocial and emotional functioning (Dunn et al. 2003, Dunn et al. 2006). People tend to describe a good quality of life in terms of happiness, contentment or fulfilment. Aristotle suggested that mankind holds various views on what happiness is and “often the same person actually changes his opinion. When he falls ill, he says that it is his health, and when he is hard up he says that it is money” (cited in Mollassiotis 1997, p573). When considering the concept of quality of life in terms of cancer diagnosis, treatment and research, Caplan (1987) provides a framework that identifies three key aspects. The first is the physical aspect, which includes physical symptoms, response to treatment, body image and mobility. The second is the psycho-social aspect and this includes psychological responses to cancer diagnosis and treatment, interpersonal relationships,
happiness, and spiritual and financial issues. The third aspect refers to a person’s individual perception of quality of life. This is influenced by their culture, philosophy, politics and the particular context or time in which it occurs. These three aspects of quality of life are considered as separate but interrelated constructs of quality of life.
In research studies related to cancer treatment and diagnosis, quality of life is generally classified as either health-related quality of life (HRQoL) or individual quality of life (IQoL). HRQoL is described as the extent to which a person’s usual expected physical, emotional and social well-being are affected by an illness and/or treatment (Cella 1998). IQoL is a much broader term that encompasses all aspects of a person’s life that they perceive influences their quality of life (Bowling 2005). The beliefs held by researchers concerned with assessing and measuring quality of life have clearly influenced how questionnaires have been developed and are being used either as a screening instrument or to measure effect in intervention studies. However the quality of the information produced by these instruments needs to be considered in order to be able to determine their ability to provide useful information.
Over the past 15 years, HRQoL has become recognised as an important outcome in the assessment and treatment of patients undergoing treatment for many different types of cancer. This is because the incidence and burden due to morbidity and mortality of cancer grows worldwide each year. The majority of cancer patients experience physical, psychosocial and emotional symptoms at one or more stages throughout their illness. Brorsson et al. (1993) describe HRQoL as a patient’s self-assessment of their ability to conduct normal daily activities and a personal evaluation of individual health and personal situation. However, some of the instruments used to assess HRQoL have been criticised because they do not take into account the subjective and dynamic nature of perceived quality of life by individuals and tend to focus on limitations and impediments, rather than on the positive and varied factors that contribute to
quality of life (Moons et al. 2004). Individual quality of life (IQoL) instruments are based on the belief that the patient is the only person who can identify domains that determine their personal quality of life and how these domains are affected by illness or disability (Hickey et al. 1996). Some researchers believe that an individualised approach to assessment of quality of life is preferable to the use of standard questionnaires (Hickey et al. 1996, Montgomery et al. 2002).
It is apparent, however, that researchers regard quality of life as a multidimensional concept. This is reflected in the many studies that use a combination of instruments that assess physical, psychological and social well- being as separate and distinct aspects of quality of life (Montgomery et al. 2002, Moons et al. 2004, Lee et al. 2005). However, there is an assumption within this methodology that the subjective or individual dimension to quality of life is captured in the data collected even though many of the instruments used comprise predetermined quality of life indices that are identified by researchers as the relevant outcomes of care. Hayry (1999) also makes this point and suggests that in addition to these assumptions, the findings in relation to particular sample groups are often generalized to the larger population when it is not appropriate to do so. Although this is a valid criticism, studies by Bowling and Windsor (2001) and Bowling et al. (2003) suggest that the issues that people feel have the greatest influence on their quality of life are varied but yet are common to most. These include positive psychological well-being, good physical and mental health, good social and personal relationships, money and independence. These studies were conducted using an older population, therefore, applicability of these findings to other age groups is questionable. However, if one considers that perhaps the individuality lies not necessarily in the dimensions themselves but rather in how a person prioritises their influence on the quality of life in different contexts and situations throughout their lives; then it is possible that these findings are relevant across all age groups. This is evident in studies where people with life threatening illness report positive developments in their quality of life even though they are experiencing high
levels of morbidity or terminal illness (Luoma and Hakamies-Blomqvist 2004). The key factor for researchers is identifying the various constructs of quality of life and ensuring that patients do the prioritizing.
3.3 Quality of Life in Patients Undergoing Stem Cell Transplantation Diagnosis of cancer and its treatment is associated with high levels of distress which is regarded as a reliable risk for adversely affecting a person’s sense of well-being (Zabora et al. 1997, 2001); however, fewer than 10% of oncology patients receive psychosocial therapy (Lee et al. 2005). The National Comprehensive Cancer Network (NCCN) defines psychological distress as ‘an unpleasant experience of an emotional, psychological, social or spiritual nature that interferes with the ability to cope with cancer treatment’ (NCCN 2003, p.5). Distress includes feelings such as powerlessness, sadness, fear/panic, depression and anxiety. These feelings can influence sleep patterns and interest in other areas of life and can, therefore, adversely affect quality of life. Interestingly, quality of life assessment does not correlate with physical morbidity in isolation but is also associated with emotional subscales such as anxiety and depression (Zittoun et al. 1999, Frick et al. 2004). This is particularly true of patients with haematological malignancies where studies have found that anxiety and depression are key risk factors of diminished quality of life and represent the most common emotional response (Molassiotis 1996, Sellick and Crooks 1999, Kelly et al. 2002, Montgomery et al. 2002).
Diagnosis of a haematological malignancy such as leukaemia usually necessitates immediate admission to a specialist haematology unit for intensive treatments that are aggressive, extremely disabling, result in an increased risk of infection, require prolonged periods in isolation and have a persistent level of uncertainty in terms of patient reaction and overall success (Feigin et al. 2000). Stem cell transplantation (SCT) or bone marrow transplantation (BMT) is one of the main treatments for haematological malignancies and although in the early stages of development as a possible treatment, it has also been used as a treatment for
certain types of solid tumours, for example some breast tumours (Zittoun et al. 1999, Feigin et al. 2000). Transplantations are classified as either autologous (patient’s own stem cells or bone marrow) or allogeneic (stem cells or bone marrow are donated by a related or unrelated person). Generally, autologous transplantations are thought to carry less risk and have less impact on quality of life than allogeneic transplants, but the chances of relapse are greater (Prieto et al. 2005). This is reflected in the many studies that do not mix these patient groups and assess quality of life in patients undergoing autologous SCTs separately (Wettergren et al. 1997, Winer et al. 1999, Feigin et al. 2000, Frick et al. 2004, Sherman et al. 2004) to patients undergoing allogeneic SCT (Johnson Vickberg et al. 2001, Edman et al. 2001, Harder et al. 2002, Kiss et al. 2002). However, many studies do not differentiate between patient groups when recruiting participants but compare the findings between them (Molassiotis et al. 1995, Molassiotis 1999, Zittoun et al. 1999, Lee et al. 2001, Prieto et al. 2005). The findings of these studies agree that, although statistical differences occur between these groups in terms of physical and psychological experiences, over one year these differences evened out in relation to overall quality of life and psychological adjustment. Neitzert (1998) concluded from a review of literature conducted to explore various quality of life issues of patients during recovery from transplantation that these samples should not be mixed due to the substantial differences in treatments and associated distinctive physical and/or emotional side effects. It is clear that inclusion of participants undergoing autologous and allogeneic SCT or BMT does not result in a homogenous sample. Zittoun et al. (1999) warn that unless from large, randomized studies with homogenous groups of patients, findings are questionable and firm conclusions cannot be drawn. This is particularly relevant to randomized controlled trials that are conducted to determine the effectiveness of treatment interventions. If patients have different physical and psychological experiences during the course of their transplant and recovery, then it is likely that they may respond differently to psychological interventions.
3.4 Measuring Levels of Anxiety, Depression and Distress
Questionnaires are used commonly to evaluate HRQoL. Many of these questionnaires comprise a list of predetermined questions relating to various aspects of quality of life, such as the Hospital Anxiety and Depression Scale (HADS) (Zigmond and Snaith 1983), the Beck Depression Inventory (BDI) (Beck et al. 1996), and the European Organisation for Research and Treatment of Cancer, Quality of Life Questionnaire (EORTC-QLQ-C30) (The EuroQoL Group 1990). Although reliable and widely used in this population, these questionnaires have been criticised because the content may not be relevant to a person’s individual life (Hickey et al. 1996). Also, they do not take account of the dynamic nature of quality of life issues and the documented difficulties associated with measuring quality of life. Instruments devised for measuring individual quality of life do not comprise lists of predetermined questions. Instead, the patient is asked to determine the factors that they regard as relevant and influential in maintaining their quality of life; for example, the Schedule for the Evaluation of Individual Quality of Life-Direct Weighting (SEIQoL-DW) (O'Boyle et al. 1995) the Patient Generated Index (PGI) (Ruta et al. 1994) and Spitzer’s Uniscale (Spitzer et al. 1981). Whilst IQoL instruments are more subjective and reflect individual quality of life determinants, there is an underlying assumption, as mentioned earlier in this chapter, that the outcomes of both HRQoL and IQoL questionnaires can be generalized to the relevant wider population (Hayry 1999, Norman 2003). Grann and Grann (2005) go as far as suggesting that quality of life may be a more appropriate primary outcome than survival in studies that include patients with life threatening or terminal disease. The challenge for researchers is to measure and assess quality of life as an outcome in the development of physical and psychological treatments in a way that is individualized and meaningful. Otherwise the effectiveness and appropriateness of such interventions is questionable.
This is particularly relevant in comparative clinical trials in cancer treatment in which quality of life is increasingly being used as a measure of outcome (Morris
and Coyle 1994). Furthermore the U.S. Food and Drug Administration now recognises the benefits to HRQoL as a basis for approval of new anticancer drugs (Bottomley 2002) and this heightens the need for researchers to include quality of life assessment in clinical trials. The difficulty for the researcher is how to achieve this in a way that demonstrates an understanding of the unique determinants of quality of life as identified by individual patients and the meaning they attribute to these as well as identifying generic outcomes related to quality of life. It is possible for researchers to demonstrate this understanding by documenting their beliefs in relation to quality of life and how this influenced their choice of instruments. This is not common practice in most cancer studies that use constructs of quality of life as outcomes, for example anxiety, depression and distress.
Two of the most common formats for assessing health related and individual quality of life are questionnaires consisting of set determinants of quality of life with descriptive choices (mild, moderate or severe) and visual analogue scales consisting of single or multi items. Measurement tools that focus specifically on anxiety and depression as predetermined aspects of quality of life, such as the HADS and the BDI, are frequently used when assessing quality of life in patients and are among the most commonly used instruments for assessing quality of life in patients with haematological malignancies.
3.4.1 Multi-Item Instruments
The HADS is a patient self-assessment questionnaire designed for physically ill patients (Machin and Fayers 1998). It consists of 2 subscales containing 7 items each. Using a one-week timeframe, the patient rates each item on a four-point scale (0-3). This questionnaire is regarded as a valid and reliable measurement tool for both anxiety and depression as separate aspects of psychological well- being. An important requirement of instruments that assess quality of life is the ability to measure changes in quality of life over time. The HADS, which is very
widely used with patients with cancer and haematological malignancies, is known to have this ability (Montgomery et al. 2002, Katz et al. 2003).
The Beck Depression Inventory (BDI) (Beck et al. 1996) was specifically designed as a tool to measure severity of depression. It is a self-administered instrument consisting of 21 items, each of which is accompanied by four statements about the symptom of depression. The statements are rank ordered and weighted. Numerical values of 0, 1, 2, 3 are assigned to each statement to reflect the degree of severity experienced by the patient. Although used more frequently in mental health populations, this tool is reported to have moderate to high levels of validity and reliability even in cancer patients (Miranda et al. 2002, Katz et al. 2003, Love et al. 2004). The latest version of the BDI is BDI-Fast Screen (for medical patients) which is a 7-item self-report measure of depression. This version is now the recommended beck inventory for cancer patients as it removes many of the somatic type items that overlap with physical illness for example, fatigue and appetite and weight loss (Beck et al. 2000).
An instrument devised specifically for assessing quality of life in cancer patients by the European Organisation for Research and Treatment of Cancer (EORTC) is the EORTC QLQ-C30 (The EuroQoL Group 1990). This is a health-status focused quality of life questionnaire comprising 30 items grouped into nine symptom scales and six functional scales. A number of modules related to specific illness, such as head and neck, lung and breast cancer, have been developed for this tool and are included with the core questionnaire (Wisloff et al. 1996, Zittoun et al. 1999, DeHaes et al. 2000). This instrument is frequently used to assess quality of life either as the sole instrument (Hayden et al. 2004) or in conjunction with tools such as the HADS, BDI and SIEQoL-DW in patients with cancer and haematological malignancies (Wettergren et al. 1997, Keogh et al. 1998, Zittoun et al. 1999, Frick et al. 2004).
Instruments commonly used for measuring IQoL in patients with haematological malignancies include the SEIQoL-DW (O'Boyle et al. 1995) the Patient Generated Index (Ruta et al. 1994) and Spitzer’s Uniscale (Spitzer et al. 1981). The Schedule for the Evaluation of Individual Quality of Life-Direct Weighting (SEIQoL-DW) is based on the belief that the determinants of quality of life can only be identified by individuals (Montgomery et al. 2002). This is a researcher- administered questionnaire that takes approximately 30 minutes to complete and has been used across a range of clinical applications (Hickey et al. 1996, Waldron et al. 1999, Frick et al. 2004). The use of this instrument comprises 3 stages. Firstly, patients are asked to list the main five aspects of their life that influence their overall quality of life. Secondly, they are asked to rate the current level of each of these determinants on the vertical axis of a visual analogue scale with a score range of 0-100. Thirdly, they are asked to weight the importance of each of the five determinants individually out of a total score of 100. This is a useful tool because it acknowledges the subjective and dynamic nature of quality of life issues for patients. The SEIQoL-DW instrument produces a global quality of life score and a current overall score that is rated on a Visual Analogue Scale. It is widely used in assessing quality of life in cancer patients, although it is not commonly used in clinical trials; this may be because it is researcher- administered and is time consuming.
A study by Frick et al. (2004) on individual quality of life of patients undergoing autologous peripheral blood stem cell transplantation found no correlation between the scores for this tool and the EORTC QLQ-C30 scale. They concluded that patient-perceived quality of life in this patient group depended primarily on aspects of life unrelated to health and physical functioning, and identified that family and social interaction were more important. This conclusion is supported by Moons et al. (2004) and Sloan et al. (1998) who found that patients report more of the psychosocial aspects of the quality of life construct whereas physicians focus primarily on variables related to physical functioning. Another possible reason why this instrument is not used in clinical
trials is that, as it is widely known that anxiety and depression are two key factors that adversely affect quality of life in this patient group, tools that focus on measuring these subscales in particular are more relevant and informative in terms of identifying changes in as a result of a treatment or intervention in clinical trials or as a screening tool in providing individualised patient care or developing patient services.
3.4.2 Visual Analogue Scales
Sloan (2002) suggests that in an effort to ensure validity of quality of life measurement tools, clinical trials are becoming increasingly complex and that information needs can alternatively be met by asking single item questions rather than by using multi-item, multidimensional, psychometrically sound, valid and reliable instruments. Bech (1999) describes visual analogue scales as useful in facilitating the quantification of open responses because they facilitate the assessment of single or multiple dimensions of global quality of life.