The European Organization for Research and Treatment of Cancer QLQ-C30: an examination into the cultural validity and reliability of the Turkish version of the EORTC QLQ-C30

Abstract

The Turkish version of the European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire version 2.0 (EORTC QLQ-C30 v.2.0) has started to be used in clinical trials recently. The objective of the study was to evaluate the validity and reliability of the Turkish version of the EORTC QLQ-C30 v.2.0 and the correlation between the Karnofsky Performance Scale (KPS) and the EORTC QLQ-C30. Two hundred and two lung cancer patients were included in the study between January and March 2000. All the subscales met the minimal standards of reliability (Cronbach's alpha > or = 0.70). Only the role functioning scale differed among the three disease stages of patients (local, locoregional and metastatic). There was no statistically significant difference among therapy types. All interscale correlations were statistically significant (P < 0.01). The strongest correlations were found among the physical functioning, role functioning and fatigue scales. Social functioning was closely related with physical, role, emotional and cognitive functioning. The weakest correlations were between nausea/vomiting and the other scales. Global quality of life (QOL) was substantially correlated with most of the scales except cognitive functioning. The coefficients for the correlation between the items differed between 0.12 and 0.97 and all the subscales were strongly correlated with the scales which they formed. The highest correlation between the EORTC QLQ-C30 and KPS was for physical functioning (r = 0.62, P< 0.05). The Turkish version of the EORTC QLQ-C30 is a valid (by means of interscales validity) and reliable instrument for Turkish lung cancer patients and can be used in clinical studies but needs supporting by the reference data on the QOL of the Turkish population.

Psychometric Validation of the Malaysian Chinese Version of the EORTC QLQ-C30 in Colorectal Cancer Patients

“…The cognitive functioning scale showed poor internal consistency at all levels of analysis. Our findings were similar to several other validation studies involving the EORTC QLQ-C30 in many Asian countries and language settings such as China (Cheng et al, 2011), Indonesia (Perwitasari et al, 2011), Singapore (Luo et al, 2005), Korea (Yun et al, 2004), Turkey (Guzelant et al, 2004), Iran (Hajebrahimi et al, 2013), and Malaysia (breast cancer) (Yusoff N et al, 2010). All these studies reported a poor internal consistency coefficient for the cognitive functioning scale (Cronbach's alpha ranges from 0.19 to 0.67).…”

Anxiety, Depression Levels and Quality of Life in Patients with Gastrointestinal Cancer in Turkey

“…Turkish validity and reliability were assessed by Guzelant et al (2004). EORTC QLQ-C30 has three subscales: "general well-being (QL2)", "functional difficulties" and "symptoms".…”

Validity and Reliability Study of James Supportive Care Screening for Cancer Patients

“…Turkish validity and reliability of the scale was conducted by Güzelant and his friends (2004) and Cronbach alpha coefficient was found to be ≥0.70. [32,33] Validity Studies Linguistic Validity and Content Validity: First of all, original scale has been translated from English to Turkish by five experts (one psychologist, one psychological consultancy specialist, two experts specialized in the nursing related with mental health and diseases, one teacher who is graduated from English Language and Literature Division) by conducting a group translation. The Turkish form which was obtained after the translation was further translated from Turkish to English by two translators, with English being their mother tongue, who have been living in Turkey for many years as a common study conducted by them.…”