Survival has been the customary research outcome measured in calculating the effectiveness of cancer treatment. Acute and chronic complications also have been recognized and, to some degree, quantified in order to objectively compare the morbidity and mortality of different treatment modalities, including surgery, chemotherapy, and radiation therapy. With the recent attention to cost-containment in the evaluation process, treatment outcomes have expanded to include the subjective impact of treatments on quality of life (QOL) of the individual with cancer. This has accelerated research aimed at defining and measuring QOL in individuals diagnosed with cancer (and their families). From this research, the theoretical framework of QOL continues to evolve as we consider what should be measured, by whom, and in what time frame, as well as the validity and reliability of measurement tools.
Despite the lack of a specific definition, the literature supports the idea that QOL is a complex construct encompassing multiple domains. The most common domains include socioeconomic status, physical health, relationships with friends and family, and satisfaction with self.[1,2] Included within these domains are measurable parameters, such as symptom distress, functional status, rehabilitation, social dependence, life satisfaction, return to a perceived "normal life," and individual attitudes toward the disease "cancer."
Chronic physiologic effects and late complications that may result from cancer and its treatment may range from those minimally affecting an individual's activities of daily living to major complications that significantly impair organ system health and function. Research has demonstrated that, of all the identified domains, a negative change in physical health has the greatest impact on overall QOL.[3,4] In addition, the overlap between health and functional status is seen whenever individuals define their state of health by what they can or cannot do. This is important in the setting of head and neck cancer, where an individual's ability to perform appropriately in areas of eating and speaking significantly influences a wide range of behaviors, from social and family interactions to more internalized feelings of self-esteem and competence.
Quality-of-life research in the head and neck cancer population has focused primarily on functional status, symptom distress, and rehabilitation. The assessment of QOL as part of clinical practice was initiated over 40 years ago, and began with narrative and cross-sectional studies. These were followed by simple quantitative measures of various treatment-related parameters, and later by longitudinal studies of greater complexity.
Most of the early research concentrated on identifying psychosocial problems experienced by individuals with head and neck cancer. In a 1986 systematic analysis of the literature on psychosocial issues in individuals with head and neck cancer, Pruyn et al identified both the physical problems (swallowing, chewing, speech, and physical appearance) and psychosocial problems (anxiety, depression, loss of self-esteem, and uncertainty about the future) that have an impact on overall QOL. They concluded that these problems might precipitate an individual's isolation from friends, difficulties with reemployment, and social and sexual tensions within families.
In a more recent (1992) review of the literature, Gotay and Moore analyzed the methodology employed in current research on QOL after treatment for head and neck cancer in order to facilitate future studies. This analysis suggested that most studies did not assess QOL in a comprehensive or uniform fashion, with large variations among studies in the inclusion of particular domains and parameters. An individual's physical status, both directly and as it influenced functioning, was the most frequent domain assessed, whereas only a minority of studies included psychological status, spirituality, sexuality, social status, and occupational functioning. In addition, site-specific domains received the most emphasis. Most studies assessed concerns particularly important in head and neck cancer, including speech, communication, eating, and swallowing. Measurement within a specific domain was also found to differ from study to study. Some researchers selected a single tool or method to measure or evaluate a parameter, whereas others chose multiple data-collection methods. Finally, the impact of surgical treatment was given much more consideration than was the effect of radiation or chemotherapy.
Quality-of-life studies in individuals treated with radiation therapy for head and neck cancer were developed in response to the comparison of complications associated with radiation and surgery. These studies attempted to further define which QOL domains were most affected by radiation to the head and neck, as well as to validate new measurement tools.
In 1991, Rathmell et al published the results of a pilot study undertaken to determine which QOL measures would be most useful in the follow-up of patients participating in clinical trials of treatments for head and neck cancer. They found that questions relating to quality of speech, ability to eat, levels of energy and activity, and aspects of psychological well-being detected the largest effects on QOL. In addition, the level of impairment in QOL was consistently higher in patients treated with surgery plus radiotherapy than in those treated with radiotherapy alone.
QOL Assessment Instruments
During this same time period, the European Organization for Research and Treatment of Cancer (EORTC) adopted a modular approach to QOL assessment in cancer clinical trials. A core instrument, the QLQ-C30, was designed to cover a range of QOL issues relevant to a broad spectrum of cancer patients. This core instrument was designed to be supplemented by more specific subscales or modules to assess aspects of QOL of particular importance to specific subgroups of patients.
In 1992, Bjordal and Kaasa published the psychometric validation of the EORTC Core Quality of Life Questionnaire with a diagnosis-specific module for head and neck cancer patients. This was a self-reporting questionnaire (multi-item scale) designed to assess physical, cognitive, emotional, social, and role functioning. The questionnaire discriminated among patient subgroups and among acute, subacute, and late toxicities of treatment. Other disease- and treatment-related symptoms, including pain, fatigue, and emesis, were measured by means of single-item scales.
Another QOL measurement tool, the Head and Neck Radiotherapy Questionnaire (HNRQ), emerged to specifically measure acute radiation-related morbidity and QOL from the perspective of patients with head and neck cancer treated with radiotherapy. This instrument was developed by a panel of health-care workers to measure outcomes of acute radiation-induced symptoms for clinical trials of radical radiation therapy in patients with American Joint Committee on Cancer (AJCC) stage III and IV cancers of the oral cavity, oropharynx, hypopharynx, or larynx. The questionnaire was validated in a randomized double-blind trial of concomitant fluorouracil(Drug information on fluorouracil) infusional therapy or saline placebo administered intermittently during a course of radiation therapy. Three a priori constructs were identified.
The HNRQ and its domain scores all showed a change from baseline to reflect a decline in QOL with an increase in morbidity during radiotherapy and in the recovery period after treatment. In addition, the HNRQ correlated with existing toxicity indices, including the World Health Organization (WHO) stomatitis scale, Byfield stomatitis scale, and WHO skin toxicity index, as well as the Eastern Cooperative Oncology Group (ECOG) and Karnofsky (KPS) performance status scales. Finally, there was a significant difference in HNRQ scores during radiotherapy between the group that received fluorouracil and the placebo group (P = .0007).
The HNRQ differed from other existing site- and symptom-specific toxicity indices in that it provided a comprehensive assessment of several symptomatic domains to produce a summary score. In addition, it touched on issues related to psychosocial function, such as social and family interactions, outlook on the future, and depression.
From this literature review, it is apparent that valid methods of measuring certain aspects of QOL in the head and neck cancer population exist and continue to evolve. It is widely accepted that QOL research remains in its infancy in terms of definition of the domains, as well as measurement. However, for this research to influence clinical care, these tools must be used appropriately when comparing morbidity, mortality, and cost-effectiveness of different treatment options. This cannot be accomplished if the focus is strictly on developing new tools used in a few studies. Despite the limitations of many of the present tools, repetitive use and growth of these tools will provide more convincing and sound data for validating clinical practice. An example of this process is evident in a series of recently published studies addressing the issue of functional outcome as a domain of QOL in a specific population: patients with cancer of the base of tongue treated with different modalities.