Functional Assessment of Cancer Therapy (FACT-G)

1. Abstract

The Functional Assessment of Cancer Therapy – General (FACT-G) is one of the most widely utilized and rigorously validated patient-reported outcome measures (PROMs) in contemporary clinical oncology and psycho-oncology. Developed in 1993 by Dr. David F. Cella and colleagues, the instrument was engineered to quantify multidimensional health-related quality of life (HRQoL) among individuals undergoing oncological therapy across diverse primary tumor sites and clinical disease stages. Historically structured across progressive iterations, the scale evaluates patient well-being across foundational core dimensions: Physical Well-Being (PWB), Social/Family Well-Being (SWB), Emotional Well-Being (EWB), Functional Well-Being (FWB), and in earlier iterations such as Version 3, the Relationship with Doctor (RWD), supplemented by unweighted domain-specific quality-of-life impact appraisal items. In its core operational design, the instrument employs a 5-point Likert response scale ranging from 0 (“Not at all”) to 4 (“Very much”), capturing patient perceptions over a 7-day recall window. Psychometric evaluations across heterogeneous adult oncology cohorts demonstrate high reliability, with Cronbach’s alpha coefficients typically ranging from 0.65 to 0.82 for Physical Well-Being, 0.55 to 0.75 for Social Well-Being, 0.66 to 0.84 for Emotional Well-Being, 0.75 to 0.84 for Functional Well-Being, and 0.82 to 0.90 for the comprehensive FACT-G Total Score. The scale possesses confirmed multi-trait construct validity, robust convergent associations with traditional clinical performance metrics such as the Eastern Cooperative Oncology Group (ECOG) Performance Status and the Karnofsky Performance Scale (KPS), established known-groups discriminant capacity, and demonstrated longitudinal sensitivity to therapeutic response and disease trajectory.

2. Keywords

Functional Assessment of Cancer Therapy, FACT-G, health-related quality of life, psycho-oncology, psychometrics, patient-reported outcome measures, cancer clinical trials, physical well-being, emotional well-being, functional well-being, oncology assessment

3. Authors

The primary architect of the Functional Assessment of Cancer Therapy measurement system is David F. Cella, Ph.D., Ralph Seal Paffenbarger Professor and founding Chair of the Department of Medical Social Sciences at the Northwestern University Feinberg School of Medicine, and Director of the Center for Patient-Centered Outcomes within the Institute for Public Health and Medicine. Dr. Cella developed the initial instrument alongside key investigators including David S. Tulsky, Ph.D., Gerald Gray, Ph.D., Amy E. Bonomi, Ph.D., M.P.H., Elizabeth A. Hahn, M.A., and Kathleen Dineen, M.S., within the Division of Psychosocial Oncology at Rush-Presbyterian-St. Luke’s Medical Center in Chicago, Illinois. Dr. Cella served as the founding executive behind the Functional Assessment of Chronic Illness Therapy (FACIT) Measurement System. Inquiries regarding instrument licensing, scoring algorithms, and international translations may be directed to FACIT.org or via academic correspondence at [email protected].

4. Purpose

The principal purpose of the Functional Assessment of Cancer Therapy – General (FACT-G) is to deliver a concise, psychometrically sound, patient-centered instrument capable of measuring the multidimensional impact of malignant disease and its multimodal therapeutic regimens (including surgical resection, cytotoxic chemotherapy, ionizing radiation therapy, immunotherapy, and endocrine treatments) on patient daily life and subjective health perceptions. For decades, biomedical cancer research prioritized objective physiological endpoints, notably overall survival (OS), progression-free survival (PFS), radiological objective response rate (ORR), and laboratory biomarker alterations. While these parameters remain paramount to clinical prognosis, they fail to illuminate the profound physical toxicity, functional limitation, psychological distress, and social disruption experienced by patients throughout their disease trajectory.

The FACT-G was explicitly constructed to bridge this clinical-experiential divide. In therapeutic research, the scale serves as a primary or secondary endpoint in Phase II, III, and IV clinical trials, facilitating formal cost-effectiveness, comparative effectiveness, and therapeutic toxicity trade-off evaluations. Regulatory bodies such as the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) increasingly rely on validated patient-reported outcomes to balance overall survival data against the subjective symptomatic burden of investigational regimens. In routine ambulatory and inpatient clinical oncology, the FACT-G functions as a systematic screening and monitoring mechanism, identifying concealed symptomatic toxicities, escalating psychological morbidity, or catastrophic functional decrements that might otherwise escape detection during rapid clinical consultations. Furthermore, because the FACT-G forms the universal core of the broader FACIT framework, it can be seamlessly merged with tumor-specific subscales (such as FACT-B for breast cancer, FACT-L for lung cancer, and FACT-C for colorectal cancer) or symptom-specific modules (such as FACT-An for anemia and fatigue), providing unprecedented flexibility across experimental and clinical applications.

5. Psychological Construct

The latent construct quantified by the FACT-G is Health-Related Quality of Life (HRQoL) in the context of neoplastic illness. Grounded in contemporary psychometric theory, HRQoL is conceptualized not as a monolithic state, but as a hierarchical, multidimensional constellation of subjective appraisals spanning biological, behavioral, affective, and interpersonal domains of functioning. The instrument operationalizes this construct across discrete, clinically correlated dimensions:

Physical Well-Being (PWB)

The Physical Well-Being dimension measures somatic distress, bodily integrity, and physical symptoms directly attributable to malignancy or the adverse sequelae of antineoplastic therapies. This subscale evaluates severe systemic fatigue (“I have a lack of energy”), gastrointestinal distress (“I have nausea”), somatic pain (“I have pain”), treatment-related side-effect bother (“I am bothered by side effects of treatment”), generalized malaise (“In general, I feel sick” or “I feel ill”), and profound physical restriction forcing confinement to bed (“I am forced to spend time in bed”). Crucially, the physical dimension does not assess pathophysiology in an abstract medical sense, but rather the intrusive subjective distress and functional impediment imposed by these physical manifestations on the individual’s lived reality.

Social/Family Well-Being (SWB)

The Social/Family Well-Being dimension captures interpersonal connectivity, perceived emotional and instrumental support systems, familial coping cohesion, and relational intimacy. Recognizing that cancer constitutes an existential crisis that disrupts social equilibrium, this domain examines social closeness (“I feel distant from my friends” / “I feel close to my friends”), availability of emotional sustenance (“I get emotional support from my family”), broader community assistance (“I get support from my friends and neighbors”), familial acceptance of the oncological diagnosis (“My family has accepted my illness”), and the transparency of domestic dialogue (“Family communication about my illness is poor” / “I am satisfied with family communication about my illness”). It additionally encompasses vital components of human intimacy, specifically relational closeness to one’s primary support partner and sexual satisfaction (“I am satisfied with my sex life”), providing respondents with conditional skip patterns to respect privacy and individual partnership status.

Relationship with Doctor (RWD)

Present in Version 3 and foundational to the structural evolution of the FACIT measurement paradigm, the Relationship with Doctor dimension assesses the therapeutic alliance, physician-patient communication efficacy, trust, and perceived clinical accessibility. Cancer patients navigate high-stakes, terrifying medical decisions under conditions of extreme informational vulnerability. Items in this domain evaluate the patient’s intrinsic trust in medical expertise (“I have confidence in my doctor(s)”) and the availability of the physician to address urgent clinical questions and existential concerns (“My doctor is available to answer my questions”).

Emotional Well-Being (EWB)

The Emotional Well-Being dimension quantifies psychological adjustment, affective distress, existential demoralization, and cognitive anxiety evoked by the cancer diagnosis and prognosis. This subscale measures depressive symptoms (“I feel sad”), subjective pride and coping efficacy (“I am proud of how I’m coping with my illness” / “I am satisfied with how I am coping with my illness”), loss of morale and despair (“I am losing hope in the fight against my illness”), somatic and psychological apprehension (“I feel nervous”), and profound existential dread centered on mortality (“I worry about dying”) or progressive physiological deterioration (“I worry that my condition will get worse”).

Functional Well-Being (FWB)

The Functional Well-Being dimension represents the patient’s capacity to execute vital daily occupational, domestic, and recreational roles, alongside their ability to derive hedonic enjoyment and existential meaning from ongoing experience. Unlike pure physical capability, functional well-being reflects the operational synthesis of physical stamina, cognitive drive, and psychological willingness. Items probe occupational and household productivity (“I am able to work”, “My work is fulfilling”), hedonic capacity and mindfulness (“I am able to enjoy life ‘in the moment'” / “I am able to enjoy life”), cognitive-existential reconciliation (“I have accepted my illness”), restorative rest (“I am sleeping well”), sustained engagement in leisure pursuits (“I am enjoying my usual leisure pursuits”), and overarching hedonic satisfaction with present existence (“I am content with the quality of my life right now”).

6. Theoretical Framework

The architectural design of the FACT-G is anchored in modern biopsychosocial oncology and clinical psychometrics, drawing heavily upon the World Health Organization (WHO) constitution (1948), which formally defines health as a state of complete physical, mental, and social well-being, rather than merely the absence of disease or infirmity. In developing the scale, Cella (1992, 1993) synthesized contemporary psychological theory with empirical oncology to construct an operational paradigm of health-related quality of life governed by three non-negotiable theoretical postulates:

1. Multidimensionality: Quality of life cannot be reduced to a unidimensional somatic index or psychological mood score; it requires the concurrent, balanced measurement of at least four cardinal domains: physical, social/family, emotional, and functional functioning.
2. Subjectivity: True quality of life can only be authoritatively evaluated from the patient’s self-reported perspective. External clinician ratings (e.g., observer-rated toxicities or functional indices) systematically diverge from, and underestimate, the patient’s subjective symptom severity and psychological burden.
3. Temporal Dynamic and State-Trait Sensitivity: Quality of life in chronic and life-limiting illness is a dynamic state subject to fluctuations driven by therapeutic intervention, biological tumor progression, psychological adaptation, and supportive interventions, mandating a bounded, standardized recall interval (operationalized in the FACT-G as “During the past 7 days”).

The theoretical framework also integrates the Transactional Model of Stress and Coping articulated by Richard Lazarus and Susan Folkman. The onset of cancer represents a severe environmental stressor that challenges the patient’s physiological and psychological equilibrium. The individual executes continuous primary cognitive appraisals (evaluating the threat of symptoms, prognosis, and bodily change) and secondary cognitive appraisals (evaluating available personal, social, and medical resources). The items comprising the FACT-G capture both the immediate threat impact (e.g., pain, anxiety, fear of dying) and the patient’s cognitive and social coping resources (e.g., coping pride, family acceptance, physician trust, emotional support). Furthermore, the scale reflects the conceptual health-outcomes hierarchy later formalized by Wilson and Cleary (1995), linking biological and physiological variables directly to symptom status, which subsequently dictates functional status, general health perceptions, and ultimate overall quality of life.

7. Validity

The Functional Assessment of Cancer Therapy – General has been subjected to extensive empirical psychometric validation across thousands of international oncology patients spanning multiple tumor types, treatment modalities, and cultural demographics.

Content and Face Validity

The initial generation of the FACT-G item pool was achieved through an exhaustive, dual-phase qualitative and quantitative development process. Cella and colleagues (1993) conducted extensive qualitative semi-structured interviews with 15 experienced oncology healthcare providers (oncologists, oncology clinical nurse specialists, social workers, and clinical psychologists) alongside 40 active adult cancer patients representing diverse primary disease sites (breast, lung, colorectal, gynecological, head and neck, and hematological malignancies). Candidate items were iteratively drafted, evaluated for clinical relevance, cognitive clarity, and emotional sensitivity, and refined using structured patient focus groups to confirm that the domains accurately mirrored the patient experience.

Construct and Convergent Validity

Multi-trait scaling analysis and correlation matrices have repeatedly affirmed robust convergent validity. Subscales of the FACT-G demonstrate statistically significant, theoretically coherent correlations with established standardized psychological and functional instruments:

• The Physical Well-Being (PWB) and Functional Well-Being (FWB) subscales correlate strongly with clinician-rated performance measures, demonstrating Pearson correlations of r = -0.50 to -0.68 with the Eastern Cooperative Oncology Group (ECOG) Performance Status scale (where lower ECOG scores indicate superior physical functioning) and positive correlations of r = 0.52 to 0.71 with the Karnofsky Performance Scale (KPS).
• The Emotional Well-Being (EWB) subscale exhibits marked convergent validity with validated psychiatric distress instruments, demonstrating robust positive correlations with the Profile of Mood States (POMS) Total Mood Disturbance score (r = 0.60 to 0.74), the Hospital Anxiety and Depression Scale (HADS), and the Beck Depression Inventory (BDI).
• The total score and respective subscales correlate highly with concurrent cancer-specific HRQoL metrics, including the Functional Living Index – Cancer (FLIC; r = 0.75 to 0.82) and the European Organisation for Research and Treatment of Cancer core questionnaire (EORTC QLQ-C30; correlations between analogous domains ranging between r = 0.65 and 0.81).

Discriminant and Known-Groups Validity

The FACT-G displays notable known-groups discriminant capacity, consistently differentiating patient groups stratified by objective clinical markers. In foundational validation trials (Cella et al., 1993; Bonomi et al., 1996), the instrument reliably differentiated:

• Inpatient versus ambulatory outpatient cohorts, with hospitalized patients scoring significantly lower across PWB, FWB, and Total Score (p < 0.001).
• Patients classified across divergent ECOG functional status tiers (0 vs. 1 vs. 2 vs. 3+), yielding stepwise, statistically significant score declines mirroring clinical impairment.
• Active progressive disease versus disease remission/stable states, wherein patients undergoing intensive salvage chemotherapy displayed significantly elevated physical and emotional distress profiles relative to disease-free survivors.

Predictive Validity and Longitudinal Responsiveness

The FACT-G possesses demonstrated predictive validity regarding clinical oncology outcomes. Baseline scores on the Physical and Functional Well-Being subscales, as well as the composite FACT-G Total Score, have been identified in multivariable Cox proportional hazards models as independent prognostic predictors of overall survival (OS) across advanced non-small cell lung cancer, metastatic colorectal cancer, and advanced breast cancer, independent of baseline age, histological grade, and performance status. Furthermore, the scale demonstrates exceptional responsiveness to longitudinal clinical change: longitudinal studies indicate that the Minimally Important Difference (MID) representing a clinically meaningful deterioration or improvement ranges between 5 to 7 points for the FACT-G Total Score, and 2 to 3 points for each individual subscale (Cella et al., 2002).

8. Reliability

The psychometric reliability of the FACT-G has been replicated across hundreds of empirical investigations worldwide, encompassing English, Spanish, European, and Asian language translations:

Internal Consistency

Internal consistency reliability, evaluated via Cronbach’s alpha (α), consistently satisfies rigorous psychometric standards for both group-level comparison (α ≥ 0.70) and clinical decision-making (α ≥ 0.80):

• Physical Well-Being (PWB): Cronbach’s α values systematically range from 0.65 to 0.82 across heterogeneous cancer samples, reflecting coherent somatic symptom clustering.
• Social/Family Well-Being (SWB): Cronbach’s α values range from 0.55 to 0.75. The comparatively modest lower bound of this range reflects the diverse, non-redundant nature of interpersonal constructs (e.g., combining family support with sexual satisfaction).
• Relationship with Doctor (RWD; Version 3): Cronbach’s α values span from 0.40 to 0.75. The lower alpha observed in some cohorts contributed to the eventual omission of this standalone subscale from the 27-item Version 4 core instrument.
• Emotional Well-Being (EWB): Cronbach’s α values consistently fall between 0.66 and 0.84, demonstrating high internal consistency in evaluating psychological distress and coping.
• Functional Well-Being (FWB): Cronbach’s α values range reliably from 0.75 to 0.84, confirming strong structural unity among daily occupational, hedonic, and existential functioning items.
• FACT-G Total Score: The composite instrument consistently demonstrates excellent internal consistency, with global Cronbach’s α coefficients between 0.82 and 0.90 across major validation trials.

Test-Retest Reliability and Stability

Temporal stability evaluated using test-retest methodology across stable cancer patients reassessed within 3 to 7 days demonstrates exceptional reproducibility. Intraclass Correlation Coefficients (ICCs) and Pearson correlation coefficients consistently exceed acceptable thresholds:

• Physical Well-Being: r = 0.82 to 0.88
• Social/Family Well-Being: r = 0.78 to 0.84
• Relationship with Doctor: r = 0.72 to 0.81
• Emotional Well-Being: r = 0.80 to 0.85
• Functional Well-Being: r = 0.84 to 0.90
• FACT-G Total Score: r = 0.85 to 0.92

The Standard Error of Measurement (SEM) across published cohorts remains small relative to total score ranges (typically 3.0 to 4.5 points for the total instrument), affirming that the FACT-G provides stable, low-noise measurements suitable for serial monitoring across oncology trajectories.

9. Factor Analysis

The internal dimensionality of the FACT-G has been extensively investigated through both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA).

Exploratory Factor Analysis (EFA)

During original instrument calibration (Cella et al., 1993), principal component analysis and maximum likelihood factor extraction utilizing both orthogonal (Varimax) and oblique (Promax) rotations revealed distinct latent structures corresponding directly to the hypothesized conceptual domains. In Version 3, five primary factors emerged with eigenvalues exceeding 1.0 (Kaiser criterion), collectively accounting for greater than 55% of the total variance across items. The primary factors aligned with somatic symptom burden (PWB), relational and communicative assets (SWB), medical trust (RWD), affective distress and demoralization (EWB), and occupational/hedonic capacity (FWB). Item factor loadings on their primary theoretical dimensions typically ranged between 0.45 and 0.82, with minimal problematic cross-loadings (< 0.30 on non-target factors), verifying high multi-trait discriminatory structure.

Confirmatory Factor Analysis (CFA)

Subsequent structural equation modeling across broad international oncology populations has confirmed the theoretical factor organization. Confirmatory factor analytic investigations evaluating the instrument demonstrate strong model fit metrics across both independent and hierarchical second-order models (where the primary domains load onto a overarching second-order global HRQoL construct):

• Root Mean Square Error of Approximation (RMSEA): typically 0.045 to 0.058 (indicating excellent absolute fit < 0.06).
• Comparative Fit Index (CFI): consistently ranges from 0.92 to 0.96 across diverse tumor groups.
• Tucker-Lewis Index (TLI): systematically > 0.91.
• Standardized Root Mean Square Residual (SRMR): consistently ≤ 0.05.

Invariance testing (measurement equivalence) utilizing multigroup CFA has verified metric, scalar, and structural invariance across male and female oncology patients, age stratifications (< 65 versus ≥ 65 years), and distinct cancer sites (e.g., breast versus prostate versus colorectal carcinoma), confirming that the instrument measures identical latent constructs with uniform precision across diverse demographic and clinical populations.

10. Instrument / Measurement Tool

The FACT-G is a structured, multidimensional, self-administered patient-reported outcome questionnaire designed for paper-and-pencil completion, electronic clinical capture (ePRO), tablet administration, or structured clinical interview.

• Instrument Designation: Functional Assessment of Cancer Therapy – General (FACT-G)
• Construct Measured: Multidimensional Health-Related Quality of Life (HRQoL) in oncology
• Target Population: Adult patients (aged 18 years and older) diagnosed with malignant neoplasms across all stages and therapeutic settings
• Administration Format: Self-report questionnaire, structured interview, or validated electronic PRO portal
• Administration Time: Typically 5 to 10 minutes
• Recall Period: Past 7 days (“During the past 7 days” / “During all the past 7 days”)
• Structural Item Composition (Version 3 vs. Version 4):
  • Version 3 (Comprehensive Source Material): 33 total items comprising 28 Likert items distributed across 5 domains (Physical Well-Being: 7 items; Social/Family Well-Being: 7 items; Relationship with Doctor: 2 items; Emotional Well-Being: 5 items; Functional Well-Being: 7 items) plus 5 unweighted visual analogue/numerical rating scale impact questions (scored 0 to 10) assessing the subjective magnitude to which each well-being dimension directly impacts overall quality of life.
  • Version 4 (Modern Standard Core): 27 items structured across 4 domains (PWB: 7 items; SWB: 7 items; EWB: 6 items; FWB: 7 items), having retired the separate Relationship with Doctor domain and individual unweighted 0-10 impact rating items.
• Standard Response Scale: 5-point Likert scale:
  • 0 = Not at all
  • 1 = A little bit
  • 2 = Some-what / A little bit
  • 3 = Quite a bit
  • 4 = Very much
• Domain Quality-of-Life Impact Rating Scale (Version 3): 11-point numerical rating scale:
  • 0 = Not at all to 10 = Very much so
• Scoring and Directionality Rules:
  • Directionality Principle: High scores on all subscales and the composite scale reflect superior health-related quality of life and lower symptom burden.
  • Reverse Scoring: All negatively phrased symptom items (e.g., “I have a lack of energy”, “I have nausea”, “I feel sad”, “I worry about dying”) must be reverse-scored prior to aggregation using the formula: Reversed Score = 4 - Patient Response.
  • Direct Scoring: Positively phrased items (e.g., “I feel close to my friends”, “I am sleeping well”, “I am content with the quality of my life right now”) are summed directly without modification.
  • Subscale Ranges:
    • Physical Well-Being (7 items): Score range 0 to 28
    • Social/Family Well-Being (7 items): Score range 0 to 28
    • Relationship with Doctor (Version 3; 2 items): Score range 0 to 8
    • Emotional Well-Being (Version 3; 5 items): Score range 0 to 20 (Version 4; 6 items: 0 to 24)
    • Functional Well-Being (7 items): Score range 0 to 28
  • Handling Missing Data (The 50% Rule): If individual items within a subscale are missing, subscale scores can be prorated provided more than 50% of the items within that specific domain were answered. The standard FACIT prorating equation is:
    
    Prorated Subscale Score = [Sum of answered subscale items] × [Total number of items in subscale] / [Number of items answered]

11. Permissions & Fee and Test Year

The Functional Assessment of Cancer Therapy – General was first published in 1993 by David F. Cella, Ph.D., and his research team. The instrument, its derivative cancer-specific subscales, and all international translations are copyrighted intellectual property managed by FACIT.org (FACITtrans.org).

• Non-Commercial and Academic Research: The FACT-G is made accessible free of charge (royalty-free) to non-funded academic researchers, registered non-profit academic institutions, healthcare practitioners using the tool for routine clinical care, and unfunded student dissertations, subject to formal online registration and agreement to FACIT copyright and scoring conditions.
• Commercial and Industry-Sponsored Clinical Trials: For-profit healthcare enterprises, pharmaceutical corporations, contract research organizations (CROs), and funded commercial clinical trials require a formal licensing agreement, user fee schedule, and authorization from FACIT.org prior to deployment.
• Translations and Custom Adaptations: More than 80 certified linguistic translations exist, translated using strict international cross-cultural methodologies including dual forward translations, reconciliations, backward translation, and cognitive debriefing. Modifying item phrasing or reformatting response scales without explicit written authorization from FACIT.org invalidates instrument certification.

12. References

Below is a comprehensive list of peer-reviewed foundational literature documenting the development, psychometric properties, and clinical validation of the FACT-G measurement system:

• Bonomi, A. E., Cella, D. F., Hahn, E. A., Webster, K., Hudgens, S., & Rothrock, N. (1996). Multilingual translation of the Functional Assessment of Cancer Therapy (FACT) quality of life measurement system. Quality of Life Research, 5(3), 309–320. https://doi.org/10.1007/BF00433915
• Brady, M. J., Cella, D. F., Mo, F., Bonomi, A. E., Tulsky, D. S., Lloyd, S. R., & Shiomoto, G. (1997). Reliability and validity of the Functional Assessment of Cancer Therapy-Breast quality-of-life instrument. Journal of Clinical Oncology, 15(3), 974–986. https://doi.org/10.1200/JCO.1997.15.3.974
• Cella, D. F. (1992). Quality of life: The concept. Journal of Palliative Care, 8(3), 8–13. https://doi.org/10.1177/082585979200800303
• Cella, D. F. (1993). Quality of life: Concepts and definition. Journal of Pain and Symptom Management, 9(3), 186–192. https://doi.org/10.1016/0885-3924(94)90129-5
• Cella, D. F., Tulsky, D. S., Gray, G., Sarafian, B., Linn, E., Bonomi, A., Silberman, M., Yellen, S. B., Winicour, P., & Brannon, J. (1993). The Functional Assessment of Cancer Therapy scale: Development and validation of the general measure. Journal of Clinical Oncology, 11(3), 570–579. https://doi.org/10.1200/JCO.1993.11.3.570
• Cella, D. F., Bonomi, A. E., Lloyd, S. R., Tulsky, D. S., Kaplan, E., & Bonomi, P. (1995). Reliability and validity of the Functional Assessment of Cancer Therapy-Lung (FACT-L) quality of life instrument. Lung Cancer, 12(3), 199–220. https://doi.org/10.1016/0169-5002(95)00450-U
• Cella, D. F., & Bonomi, A. E. (1996). The Functional Assessment of Cancer Therapy (FACT) and Functional Assessment of HIV Infection (FAHI) quality of life measurement system. In B. Spilker (Ed.), Quality of Life and Pharmacoeconomics in Clinical Trials (pp. 203–214). Philadelphia: Lippincott-Raven.
• Cella, D. (1997). The Functional Assessment of Cancer Therapy-Anemia (FACT-An) Scale: A new tool for the assessment of outcomes in cancer anemia and fatigue. Seminars in Hematology, 34(3 Suppl 2), 13–19.
• Cella, D., Hernandez, L., Bonomi, A. E., Corona, M., Vaquero, M., Shiomoto, G., & Baez, L. (1998). Spanish language translation and initial validation of the Functional Assessment of Cancer Therapy quality-of-life instrument. Medical Care, 36(9), 1407–1418. https://doi.org/10.1097/00005650-199809000-00012
• Cella, D., Hahn, E. A., & Dineen, K. (2002). Meaningful change in cancer-specific quality of life scores: Differences between improvement and worsening. Quality of Life Research, 11(3), 207–221. https://doi.org/10.1023/A:1015276414526
• Fairclough, D. L., & Cella, D. F. (1996). Functional Assessment of Cancer Therapy (FACT-G): Non-response to individual questions. Quality of Life Research, 5(3), 321–329. https://doi.org/10.1007/BF00433916
• McDowell, I. (2006). Measuring Health: A Guide to Rating Scales and Questionnaires (3rd ed.). Oxford University Press. https://doi.org/10.1093/acprof:oso/9780195165678.001.0001
• Mullin, V., Cella, D., Chang, C.-H., & Peterman, A. H. (2000). Development of three African language translations of the FACT-G. Quality of Life Research, 9(2), 139–149. https://doi.org/10.1023/A:1008985108420
• Novik, A. A., Ionova, T. I., Fedorenko, D. A., Kishtovich, A. V., & Cella, D. (2000). Sensitivity of FACT-G in quality of life assessment of lung cancer patients after radical surgery. Quality of Life Newsletter, 24, 12.
• Ward, W. L., Hahn, E. A., Mo, F., Hernandez, L., Tulsky, D. S., & Cella, D. (1999). Reliability and validity of the Functional Assessment of Cancer Therapy-Colorectal (FACT-C) quality of life instrument. Quality of Life Research, 8(3), 181–195. https://doi.org/10.1023/A:1008821826499

13. Items of the Scale (Questionnaire)