Quality of Life After Radiation Therapy for Base of Tongue Cancer

November 1, 1996

The article by Moore provides an example of much needed research evaluating clinical outcomes in head and neck oncology. Measuring the quality of life (QOL) of patients with head and neck cancer presents some unique challenges. First, head and neck cancer profoundly influences some of the most fundamental functions of life, including breathing, eating, and communication. Second, treatment of head and neck cancer does not always improve these functional deficits, and in many instances, the treatment itself results in further deterioration of these functions. Finally, "traditional" outcome measures (disease-free survival, overall survival, local and regional control, response rates) do not adequately assess the global impact of this disease and/or its treatment on patients' perception of life satisfaction.

The article by Moore provides an example of much needed researchevaluating clinical outcomes in head and neck oncology. Measuringthe quality of life (QOL) of patients with head and neck cancerpresents some unique challenges. First, head and neck cancer profoundlyinfluences some of the most fundamental functions of life, includingbreathing, eating, and communication. Second, treatment of headand neck cancer does not always improve these functional deficits,and in many instances, the treatment itself results in furtherdeterioration of these functions. Finally, "traditional"outcome measures (disease-free survival, overall survival, localand regional control, response rates) do not adequately assessthe global impact of this disease and/or its treatment on patients'perception of life satisfaction.

Sometimes the treatments used for head and neck cancer, whichinclude surgery, radiation, or chemotherapy (used as single modalitiesor in any combination), can result in disabilities that patientsperceive as being worse than the untreated disease.[1,2] Therefore,there is a need for the use of validated instruments to quantifythe impact of head and neck cancer and its treatment on patients'QOL.

Although interest in the incorporation of QOL outcome measuresin head and neck cancer has recently increased, several questionsremain unanswered: Which instrument should be used? Is a general,disease-specific, or site-specific instrument most appropriatein this patient population? Is head and neck cancer a single diseaseor a heterogeneous collection of the same disease at differentsubsites? Are certain instruments more specific to some treatmentmodalities than others? What is the most appropriate frequencyand duration of QOL assessment in head and neck cancer patients?Who should administer the questionnaires? This discussion willexplore some of the controversy surrounding these issues.

Which QOL Instrument to Use?

General vs Disease Specific--Health-related QOL instrumentscan be divided into general and disease-specific instruments.General measures assess the overall impact of patients' healthstatus on their QOL. Examples of such instruments include theSickness Impact Profile (SIP),[3] the Quality of Well-Being Scale,[4]and the Medical Outcome Study (MOS).[5] General instruments employdetailed questionnaires, including numerous items that cover abroad spectrum of functional, physical, psychological, and socialdomains. Their main advantage is that they can be utilized acrossa broad range of patients, and allow for comparison of resultsacross different diseases. The disadvantage of general instrumentsis their lack of responsiveness to the peculiar aspects of a particulardisease process, such as cancer.

Disease-specific instruments are designed to evaluate in moredepth the intricate features of a particular disease process.Examples of cancer-specific instruments include different performancestatus measures (Karnofsky,[6] ECOG,[7] AJCC[8]), the Qualityof Life Index,[9] and the Functional Living Index-Cancer, or FLIC).[10]These instruments are often more responsive to changes in cancerpatients' health status over time than are general measures.

Site-Specific vs Modular Instruments--Although the diagnosisand treatment of cancer result in certain salient and well-recognizedeffects common to all cancer patients, the location of diseaseposes specific problems unique to that particular site. The headand neck region provides a very dramatic example of this concept.The devastating effects of head and neck cancer and/or its treatmenton voice, speech, mastication, deglutition, sense of taste and/orsmell, and facial appearance are peculiar to this patient population.Site-specific instruments are designed to be more responsive thancancer-specific instruments in measuring those difficulties thatare most pronounced at a particular site. Examples of head andneck-specific instruments include the Performance Status Scalefor Head and Neck Cancer Patients (PSS-HN)[11] used in the Moorearticle, the University of Washington Head and Neck Questionnaire(UW QOL),[12] and the Head and Neck Radiation Therapy Questionnaire(HNRQ).[13]

Site-specific instruments may lack some of the broader assessmentof the impact of cancer on patients' QOL. To combine the benefitsof both approaches, some instruments have been designed with ameasurement strategy called the "modular approach."In this approach, a core disease-specific instrument is used forall patients with the diagnosis of cancer, supplemented with asite-specific instrument that varies with the site of origin ormethod of treatment. Examples of such instruments are the FunctionalAssessment of Cancer Therapy (FACT)[reference 14 and personalcommunication, D. F. Cella, md, January 10, 1992] and the EuropeanOrganization for Research and Treatment of Cancer (EORTC) CoreQuality of Life Questionnaire,[15] both of which have supplementaryhead and neck modules. This modular approach may prove to be idealin measuring QOL in patients with head and neck cancer.

Is Head and Neck Cancer a Single Disease?

Patients with head and neck cancer have certain similarities.Most of these patients give a long-standing history of heavy tobaccoand alcohol consumption. These carcinogenic factors also predisposepatients to common comorbidities, including chronic obstructivepulmonary disease, pancreatitis, cirrhosis, delirium tremens,and second malignancies, especially lung cancer. These comorbiditieshave a somewhat uniform impact on the QOL of head and neck cancerpatients regardless of the primary site.

Conversely, the biologic behavior, and hence, outcome of headand neck cancer depend largely on the site of disease (eg, larynx,oral cavity, nasopharynx, and so on). Also, the disabilities thatresult from head and neck cancer or its treatment vary widelyaccording to the site of involvement. The article by Moore presentsan excellent example of measuring QOL in a specific subsite ofa relatively homogeneous patient population with base of tonguecancer.

Treatment-Specific QOL Measures

Some QOL instruments are better suited to measuring the morbidityof surgical extirpation of head and neck cancer, while othersare more sensitive to the morbidity associated with radiationand/or chemotherapy. For instance, the UW QOL[12] includes domainsthat assess pain, disfigurement, chewing, swallowing, speech,shoulder disability, activity, recreation, and employment--allof which are profoundly affected by surgical ablation of headand neck cancer (eg, laryngectomy, glossectomy, mandibulectomy,neck dissection). On the other hand, the HNRQ[13] contains itemsdetailing the assessment of mucositis, skin reactions, xerostomia,nausea, vomiting, appetite, and energy level, among others. Theseitems are more profoundly influenced by radiation and/or chemotherapythan by surgery.

In the article by Moore, the PSS-HN was chosen to assess the QOLof patients treated primarily with radiation therapy. The threedomains detailed by the PSS-HN[11] (eating in public, understandabilityof speech, and normalcy of diet) are more likely to be influencedby surgical ablation of head and neck cancer than by radiationtherapy. The PSS-HN was initially validated in patients treatedlargely with surgery, and its results were highly responsive tothe extent of surgical resection.[11] This instrument does notspecifically assess radiation-induced morbidity. This probablyleads to underestimation of the effects of radiation on the QOLof these patients. It also makes comparison between the two modalitiesof treatment (surgery vs radiation) less meaningful. An instrumentspecifically designed to assess radiation-induced morbidity (eg,the HNRQ[13] or EORTC[15]) would have been more appropriate ina patient population treated primarily with radiation.

Frequency and Duration of QOL Assessment

Temporal factors greatly influence the results of QOL assessment.When measuring the acute morbidity of a disease process or itstreatment, one should measure QOL frequently. In the case of radiationtherapy or chemotherapy, QOL measurement probably should be donebefore treatment, at weekly or biweekly intervals during treatment,and for several weeks afterward.

Some therapeutic modalities have delayed effects (months or years)on QOL, and thus, require delayed measurement. If such a determinationis not performed, the impact of this delayed morbidity may bemissed. An example of this pitfall is the study by Harrison etal cited in the Moore article. Harrison et al[16] used the PSS-HNin patients with base of tongue cancer treated with surgery and/orradiation. The radiation-therapy group had consistently betterscores, and the authors recommended using radiation as a primarymodality of therapy because the radiation-therapy group had survivalrates equal to those of the surgery group but had better QOL.

Several caveats about these conclusions are worth mentioning.First, the previously mentioned limitation of the PSS-HN beinga more surgery-sensitive than radia-

tion-sensitive instrument applies to the Harrison et al studyas well as to the Moore study. Second, Harrison et al gave noindication of the extent of surgical resection. Finally, and perhapsmost importantly, the Harrison et al[16] study did not reportlong-term QOL scores.

These issues are crucial because before any modality, either surgicalor radiotherapeutic, becomes accepted as the primary treatmentfor any particular type of head and neck cancer, its long-termeffect on QOL should be known. For instance, Larson et al[17]reported on long-term complications in 128 patients who had cancerof the oral cavity and oropharynx treated with radiation therapyalone and who were free of disease for at least 5 years. The studyreported a 56.3% overall incidence of soft-tissue ulceration,osteoradionecrosis, or spontaneous fracture. Osteoradionecrosisoccurred in 44 of 119 patients, and the incidence of this complicationincreased over time (42% within 2 years, 56% within 3 years, and82% within 5 years). Out of these 44 patients, 18 required subsequentpartial mandibulectomy or hemimandibulectomy.

This study illustrates the need for long-term QOL measurementespecially when dealing with a treatment modality that has a relativelyhigh rate of delayed complications.

Who Should Administer QOL Questionnaires?

Questionnaires on QOL can be self-reported (administered by thepatients themselves) or interviewer-reported (administered bya physician, nurse, or other professional).

The PSS-HN used in the article by Moore is an example of an interviewer-administeredquestionnaire. The main advantage of these instruments is thatthey avoid vague or incomplete answers. Their main disadvantageis that the quality of data is highly interviewer-dependent. Possibleareas of interviewer bias include their training and preconceptionsabout patients' demographics (age, sex, race, education, socialclass, and so forth), the disease process, or the treatment utilized.Several studies have demonstrated the poor correlation betweenpatients' self-ratings and interviewer-generated ratings. Currently,patient self-reporting is generally the preferred method of obtainingQOL data.

Summary

The article by Moore describes the use of a well-defined QOL instrumentin a homogeneous group of patients with base of tongue cancertreated with radiotherapy. Future studies in a similar patientpopulation should perhaps consider an instrument that is moresuited to the assessment of radiation-induced morbidity and itseffect on QOL in such patients. Other factors that may enhancethe ability to assess QOL in head and neck cancer include long-termreporting, patient-administered questionnaires, and instrumentsof the "modular" type that involve a core cancer-specificquestionnaire with a head and neck specific module.

References:

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