• INTERNATIONAL JOURNAL OF PHARMACEUTICAL MEDICINE 2000, 14:78-81 78

ORIGINAL ARTICLE

Assessment methods for quality oflife in cancer patients: the FACITmeasurement system

David Cella

Center on Outcomes Research and Education, Evanston Northwestern Healthcare, 1000 Central Street, Suite 101, Evanston, IL 60201, USA

Received 4 February 2000; accepted 9 February 2000

SummaryThe Functional Assessment of Chronic Illness Therapy (FACIT) measurement system is acollection of 27 quality of life (QOL) scales, with several more in development, targeted atthe management of chronic illnesses including cancer (FACT), human immunodeficiencyvirus (HIV) infection (FAHI), and multiple sclerosis (FAMS). The core FACIT scale(FACT-G) consists of a general questionnaire with 27 items related to four dimensions ofhealth: physical, functional, social, and emotional well-being. There are also symptom- andtreatment-specific scales as well as assessments for other areas of concern (e.g. spiritualityand palliative care). Many of the questionnaires are available in over 30 languages. Thevalidity, reliability, and the sensitivity to change in health status over time of the FACITquestionnaires have been well documented. Currently, the FACIT scales have beenimplemented in Phase II and III clinical trials and other cancer-related treatmentevaluations. Future efforts in improving the FACIT measurement system includeidentification of items that are sensitive to specific patient populations, collection of datato establish national normative and bench mark scores, construction of a QOL item bank,and development of computerized adaptive testing programmes (CAT) to measureprecisely a given concept based on ongoing responses.

Keywords: cancer, quality of life, FACIT, assessment, questionnaire development.

Introduction

When evaluating outcomes of chronic disease therapy in clinicaltrials or in clinical practice, clinicians are concerned with threekey issues: quantity of life (i.e. duration of survival), quality oflife (i.e. patient well-being), and the cost of therapy. All threeparameters are measurable; however, quality of life (QOL) maybe measured using one of several non-equivalent metrics. Thequality of life (QOL) questionnaire developed by the EuropeanOrganization for Research and Treatment of Cancer (EORTC)and the Functional Assessment of Chronic Illness Therapy(FACIT) measurement system are currently the two most widelyused QOL measuring tools in cancer clinical trials. The previousarticle in this issue by Theresa Young discusses the developmentprocess and guidelines for the EORTC questionnaires. Thisarticle focuses on the development of the Functional Assessmentof Chronic Illness Therapy (FACIT) measurement system. The

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FACIT is a collection of 27 QOL questionnaires, with others indevelopment, targeted at the management of chronic illnessesincluding cancer, human immunodeficiency virus (HIV) infec­tion, and multiple sclerosis. The term FACIT was recentlyintroduced to replace the familiar FACT-General (FACT-G)measurement system because its scope now encompasseschronic illnesses other than cancer.

QOL dimensions

Measurement of QOL requires a multidimensional approach toquantification of subjective variables. The FACIT measurementsystem assesses four QOL dimensions: physical, functional,social, and emotional well-being (Figure 1). Physical well-beingincludes disease symptoms and treatment side effects, whilefunctional well-being refers to the ability of the patient toperform activities of daily living and role performance. Social or

2000 <> VOL 14, NO 2

Figure 1 Quality of life dimensions.

QUALITY OF LIFE IN CANCER PATIENTS 79

FACIT

Emotionalwell-being-coping- distress

*-enjoyment

Physical well-being- disease symptoms- treatment side effects

Functional well-being-ADLs- role performance

The FACIT measurement system, an expansion of the FACTsystem to cover other chronic diseases, consists of 27 multi­dimensional self-reported QOL questionnaires, with severalothers in development, comprising over 300 questions. Thequestionnaires are available in many languages (over 30 forsome scales). Currently, the FACIT includes questionnairesspecific to cancer (FACT), multiple sclerosis (FAMS) and HIVinfection (FAHI). There are also symptom- and treatment­specific scales as well as assessments for other areas of concern(e.g. spirituality and palliative care).

Translation of questionnairesTo ensure consistency in the type of information solicited bydifferent language versions of the same questionnaire, it isimportant to have a rigorous and thorough translation proce­dure. It is critical that the questions be culturally relevant to

FACT scalesFACT, one of the FACIT scales, consists of a generalquestionnaire (FACT-G) with 27 items related to four dimen­sions of health (physical, functional, social, and emotional well­being), plus disease-specific subscales that address issues relatedto a specific disease and its treatment (Table 1). For example,the prostate cancer subscale includes questions related to painand urinary, sexual and bowel function. Responses to questionsare recorded on a 5-point Likert scale (i.e. O=not at all; l=alittle bit; 2=somewhat; 3= quite a bit; 4=very much). Therefore,the scores for the physical well-being scale consisting of 7 itemscan range from 0 to 28. Other FACIT scales that are currentlyunder development include ones for endometrial cancer,melanoma, lymphoma, radiation therapy, and treatment satis­faction.

Social well-being- social activity/support- relationship quality- family well-being

family well-being refers to the quality of relationship andcommunication with family members; and emotional well-beingcomprises a wide range of psychological effects of the disease,from coping with the illness and distress to enjoying life despiteones illness.

QOL assessment in clinical trials

There are several reasons why QOL is assessed in clinical trials.QOL is usually not measured in phase I clinical trials; however,use of QOL measurements in phase II clinical trials hasincreased in recent years. This has allowed clinicians to ascertainpatient assessments of a new therapy earlier in clinical testingthan before. This has included information on the frequency,severity, and burden of side effects. It has also become possibleto identify discrepancies between physician- and patient­reported side effects. Assessment of QOL measures in phaseII clinical trials may also aid in establishing a definition ofresponse in diseases where response may be difficult to quantify,such as prostate cancer, or where benefits to patients may occurin the absence of measurable tumour shrinkage [1]. QOL datafrom phase II trials can also be valuable in designing QOLendpoints and timing in subsequent phase III trials. QOLassessments are usually made in phase III clinical oncology trialsto broaden the evaluation beyond the two classic endpoints ofresponse rate and survival. QOL data from these trials allowclinicians to assess the impact of treatment on the multipledimensions of daily living, and to examine those aspects of QOLthat are relevant to clinical decision-making when treatingcancer patients.

Interested clinicians must select an appropriate QOL mea­surement tool from a wide variety of generic and disease-specificquestionnaires. An instrument should have acceptable reliabilityand validity, and be sensitive to clinically significant changes inphysical function and ability to perform activities of daily living.It is also important that the questionnaire be brief (e.g. 10-15minutes in a multicentre trial) and require minimal effort fromthe patient and staff to complete. The questionnaire should havenon-offensive wording, addressing the most important generichealth concepts and specific issues that are relevant to thedisease and therapy being studied [2].

Table 1. FACIT Subscales

Cancer-specific

BreastBladderBrainCentral nervous systemCervicalColon

Symptom-specific

Anorexia/cachexiaAnaemiaDiarrhoeaEndocrine symptoms

Treatment-specific

Bone marrow transplantationBiological response modifiersNeurotoxicityTaxaneToxicity

Non-cancer-specific

HIV infectionMultiple sclerosisSpiritual well-beingNon-life-threatening conditions

OesophagealHead and neckHepatobiliaryLungOvarianProstate

FatigueFaecal incontinenceUrinary incontinence

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80 CELLA

Conclusions

In summary, different approaches to measurement of consis­tency among various QOL instruments may offer complemen­tary results. Concurrent application of both classical ('true

Figure 2 Graphical representation of item response theory model. For awell-defined concept, the item response theory model can develop ahierarchy for the items measuring that concept. The fewer patientsresponding they have a problem with an item the 'easier' the item. When asufficient number of items covering a broad

Figure 3 Precision testing. The CARES, EORTC, FACT, Quality of LifeIndex (QLI), and RAND-36 instruments were administered to a singlegroup of patients. Using the Rasch measurement these instruments werethen given a total score. The lower the logit standard error (SE) the moreaccurate a particular scale is. Adapted with

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has enough questions covering enough of the 'difficulty'spectrum of a well-defined concept (such as physical well-beingor health), then one can use the item response theory model tolocate any person along that dimension based upon thecombination of responses to the questions. Patients with anoverall good quality of life will tend to have answers at one endof the scale, patients with poor quality of life at the other (Figure2).

Comparison of precision, using the Rasch measurementmodel, between QOL instruments revealed that certain ques­tionnaires were more precise at specific areas of the responsecurve (Figure 3) [4]. For instance, the FACT and the CancerRehabilitation Evaluation System (CARES) systems were moreprecise (i.e. had a lower standard error) at intermediate QOLvalues, whereas the RAND-36 was more precise at high and lowQOL scores, and the EORTC QLQ-C30 was more precise atlow QOL scores [4].Evaluating measurement properties

There are a number of ways to evaluate measurement propertiesof questionnaires such as the FACIT system. Reliability andvalidity, including responsiveness to change, can be evaluatedusing classical (true score) test theory or item response theory.FACIT questionnaires have been subjected to both approachesin evaluating its measurement properties. For example, regard­ing reliability, classical approaches to evaluating the internalconsistency of the questions in various subscales, or the stability(test-retest reliability) of the scores produced, have consistentlyyielded positive results. Comparable results have also resultedfrom using an item response theory-based measurement modelto measure internal consistency. Furthermore, using itemresponse theory, we can compare instruments such as theFACT-G and the EORTC QLQ-C30 directly to one another byplacing all of the questions to a common metric. Structuralequation modelling with confirmatory factor analysis can also beused to determine if a similar structure of responses is obtainedfrom patients of different cultures. The item response theoryapproach (e.g. Rasch measurement) can be used to create acommon metric across available questionnaires. Therefore, thequestionnaires can be compared to one another and patientswho complete one questionnaire can be compared to those whomay have completed a different questionnaire.

One component of item response theory is the arranging ofitems relative to one another based upon the hierarchy of what isbeing measured. For example, a large number of patients mayanswer that they have difficulty walking while a much smallernumber may respond that they suffer from dizziness. Hence, theprobability of any given patient answering a problem withdizziness is lower than the probability of that patient enduringtrouble walking. Dizziness is then classified to be a more'difficult' (low probability) item than trouble walking [4]. If one

Implementation of FA CITCurrently, the FACIT measurement system has been incorpo­rated into several clinical trials and in related treatmentevaluations. It has also been utilized as an intervention tool inclinical management of both physical and psychological illness,and as an outcomes measure in health practice studies. Otherresearch includes assessment of cross-cultural and cross-instru­ment equivalence, and determination of the clinical significanceof the QOL data obtained using these instruments.

their intended audience while retammg semantic equivalence(i.e. the underlying meaning) with the original. The method ofassessment should be comparable for all language versions of thesame questionnaire so that the responses are interpreted thesame way and the underlying concepts are measured consistentlyacross languages. Some FACIT scales are now available in 33different languages. Unlike the EORTC questionnaires thathave multiple versions for different dialects of a language (e.g.Canadian French and Continental French), single versions ofFrench, Spanish and Portuguese have been harmonized acrossdialects for the FACIT scales. A cross-language validation studyof the FACT-Anaemia (FACT-An) scale in six differentlanguages demonstrated consistent results, across languageswith very little evidence that questions performed differently inone country versus another. This suggests that with propertranslation methodology separate dialect versions of the samelanguage are not necessary [3].

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score') and item response theory may aid in translation andrevalidation of a questionnaire in different populations. Futureefforts in improving the FACIT measurement system includeselection of items that are sensitive to specific patient popula­tions, construction of a QOL item pool (i.e. item banking) incollaboration with RAND, EORTC and other colleagues,collection of data to establish stable item parameters, anddevelopment of computerized adaptive testing (CAT) programsto more precisely measure a given concept based on responses toquestions selected by an item-response theory-driven algorithm.

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QUALITY OF LIFE IN CANCER PATIENTS 81

References

1. Moore MJ, Osoba D,Murphy K,Tannock IF,Armitage A, Findlay B,Coppin C,Neville A, Venner P,Wilson J. Use of palliative end points to evaluate the ef­fects of mitoxantrone and low-dose prednisone in patients with hormonallyresistant prostate cancer. J Clin Onco/1994; 12:689-94.

2. Cella DF.Measuring quality of life in palliative care. Semin Onco/1995; 22(2SuppI3):73-81.

3. Chang C,Bresnahan B,Gagnon D,Lent L, Zagari M, McNulty P,VercammenE,Cella D.Cross-language validation ofthe Functional Assessment of Can­cerTherapy - Anemia (FACT-An) questionnaire. EurJ Cancer1999; 35(SuppI4):S359.

4. Chang C-H, Cella D.Equating health-related quality of life instruments inapplied oncology settings. Physical Medicine and Rehabilitation: State ofthe Art Reviews 1997; 11:397-406.

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