Evidence map›Paper›PMID 40905288›Full record

ArticleEuropean journal of translational myology2025

Validation of the Bulgarian versions of the EORTC QLQ-C30 and FACT-G: reliability, construct validity, and agreement in cancer survivors.

Gospodin Peykov, Hristo Bozov, Angel Uchikov, Petar Uchikov, Georgi Gelov, Desislava Stambolova, Yanna Kashilska, Maria Bojhkova, Nigyar Dzhafer, Kiril Panayotov and 1 more

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Article in European journal of translational myology, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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4 · The record

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5 · Who and what money

Authors and funding

11 authors.

Gospodin PeykovDepartment of Surgery, University Hospital "Sveta Marina", Pleven.
Hristo BozovState University of Burgas Prof. Dr. Asen Zlatarov, Burgas.
Angel UchikovDepartment of Special Surgery, Faculty of Medicine, Medical University of Plovdiv, Plovdiv.
Petar UchikovDepartment of Special Surgery, Faculty of Medicine, Medical University of Plovdiv, Plovdiv.
Georgi GelovSurgical Department, Multiprofile Hospital for Active Treatment, Haskovo.
Desislava StambolovaSurgical Department, Multiprofile Hospital for Active Treatment, Haskovo.ORCID 0009-0002-0040-0883
Yanna KashilskaDepartment of Health Management and Health Economics, Faculty of Public Health, Medical University of Plovdiv, Bulgaria; Medical Diagnostic Consultative Center "St. Archbishop Luka", Plovdiv.
Maria BojhkovaMedical College, Medical University of Plovdiv.
Nigyar DzhaferDepartment of Health Policy and Management, Faculty of Public Health "Prof. Dr. Tzecomir Vodenicharov, DSc", Medical University of Sofia.ORCID 0000-0003-3196-8359
Kiril PanayotovDepartment of Medical and Clinical Diagnostic Activities, University of Rousse "Angel Kanchev", University Hospital "Medica Rousse".
Jannis PapathanasiouDepartment of Physical and Rehabilitation Medicine, Medical University of Plovdiv, Bulgaria; Department of Physical Medicine & Rehabilitation, Medical University of Sofia.ORCID 0000-0003-2557-5508

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Health-related quality of life (HRQoL) is a critical outcome measure in oncology research and clinical care. This study aimed to translate, culturally adapt, and psychometrically validate the Bulgarian versions of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) and the Functional Assessment of Cancer Therapy-General (FACT-G), focusing on Internal Consistency (IC), Test-Retest Reliability (TRR), and Construct Validity (CV) in Cancer Survivors (CS) diagnosed with breast, lung, or colorectal cancer. A total of 235 Bulgarian CS (mean age 62.3 ± 11.2 years; 118 males, 117 females) were recruited from five tertiary care hospitals in a cross-sectional study design. The EORTC QLQ-C30 and FACT-G were translated and culturally adapted according to the official EORTC and FACIT guidelines. Psychometric evaluation included data quality (floor and ceiling effects, missing responses), IC, TRR, and CV assessed via convergent and Discriminant Validity (DV). A subsample of 78 study participants (33.2%) completed both questionnaires twice over a 14-day interval for TRR assessment. CV was supported by strong item-scale and cross-instrument correlations (r = 0.62-0.81). IC was excellent across all domains (Cronbach's α = 0.88-0.95), and TRR demonstrated high stability (ICC = 0.75-0.89). Bland-Altman analysis showed acceptable agreement, with a mean difference of 23.20 (95% CI: 21.87-24.53) and limits of agreement ranging from +3.77 to +42.63. Minimal Floor Effects (FE) were observed, while Ceiling Effects (CE) were noted in specific domains (e.g., Social Functioning (SF) and Global Health (GH) in the EORTC QLQ-C30; Social Well-Being (SWB) and Emotional Well-Being (EWB) in the FACT-G). The findings support that the Bulgarian versions of the EORTC QLQ-C30 and FACT-G are valid, reliable, and culturally appropriate instruments for evaluating HRQoL in Bulgarian CS. Their use is recommended in both clinical practice and research contexts.

Indexed as

BulgariaEORTC QLQ-C30FACT-Ghealth-related quality of lifepsychometric validation

Identifiers

PMID40905288
PMCPMC12801114

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