“…Therefore, a shortened 12-item English version (BCTOS-12) has been developed and tested recently. The study by Hennigs et al [22] showed good validity, without loss of information. In this shortened version the 12 items are assigned to two, instead of three, subscales: aesthetic and functional status.…”
PurposeTo create a Dutch translated short version of the Breast Cancer Treatment Outcome Scale (BCTOS) and validate it in patients who have completed both breast conserving surgery and adjuvant radiotherapy.MethodsThe BCTOS consists of items comparing the treated with the untreated breast. After forward and backward translation, we tested the BCTOS-12 plus 5 additional items. Two-hundred breast cancer patients treated with breast conserving therapy (BCT) between January 2016 and December 2017, were asked to complete the BCTOS items twice with a 2 week interval. The EORTC QLQ-BR23 breast and arm symptoms subscales were completed once in parallel. Feasibility was assessed by missing or non-unique answer rates and content validity with floor and ceiling effect analysis. Construct validity was evaluated with 1) principal component analysis (PCA) 2) convergent validity and 3) known groups comparison (clinical validity differentiating between patients with and without locoregional side effects). From all potential items with good feasibility, content and construct validity, items were selected for the Dutch BCTOS based on clinical validity. The relation to the EORTC QLQ-BR23 subscales and reliability was tested for the new Dutch BCTOS.ResultsHundred and one of 200 (50.5%) approached patients participated in this study, with follow-up after surgery ranging from 5 to 29 months. Feasibility was high (1.5% missing answers). Content validity testing showed a floor effect > 20% in all 17 items. PCA showed that all items loaded well (> 0.4) into the assigned subscale and revealed two distinct subscales: cosmesis and function. Based on clinical validity, item “breast shape” was replaced by “breast elevation/position” and “overall skin appearance”. Very good clinical validity (Cohen’s d = 1.38) was found for the new Dutch BCTOS-13. Correlation to the EORTC QLQ-BR23 subscales was high (ICC = 0.65–0.85) for both subscales. Test-retest reliability (Cohen’s d = 0.105) and internal consistency (Cronbach’s α =0.90) were excellent.ConclusionsPsychometric evaluation of a newly developed Dutch BCTOS-13 questionnaire in BCT patients showed excellent results, that were slightly better than the original BCTOS-22 and the shortened BCTOS-12. The good clinical validity makes the BCTOS-13 a useful tool to identify patients with unfavourable cosmetic and functional outcomes, requiring specific attention.Electronic supplementary materialThe online version of this article (10.1186/s41687-018-0085-y) contains supplementary material, which is available to authorized users.
“…Therefore, a shortened 12-item English version (BCTOS-12) has been developed and tested recently. The study by Hennigs et al [22] showed good validity, without loss of information. In this shortened version the 12 items are assigned to two, instead of three, subscales: aesthetic and functional status.…”
PurposeTo create a Dutch translated short version of the Breast Cancer Treatment Outcome Scale (BCTOS) and validate it in patients who have completed both breast conserving surgery and adjuvant radiotherapy.MethodsThe BCTOS consists of items comparing the treated with the untreated breast. After forward and backward translation, we tested the BCTOS-12 plus 5 additional items. Two-hundred breast cancer patients treated with breast conserving therapy (BCT) between January 2016 and December 2017, were asked to complete the BCTOS items twice with a 2 week interval. The EORTC QLQ-BR23 breast and arm symptoms subscales were completed once in parallel. Feasibility was assessed by missing or non-unique answer rates and content validity with floor and ceiling effect analysis. Construct validity was evaluated with 1) principal component analysis (PCA) 2) convergent validity and 3) known groups comparison (clinical validity differentiating between patients with and without locoregional side effects). From all potential items with good feasibility, content and construct validity, items were selected for the Dutch BCTOS based on clinical validity. The relation to the EORTC QLQ-BR23 subscales and reliability was tested for the new Dutch BCTOS.ResultsHundred and one of 200 (50.5%) approached patients participated in this study, with follow-up after surgery ranging from 5 to 29 months. Feasibility was high (1.5% missing answers). Content validity testing showed a floor effect > 20% in all 17 items. PCA showed that all items loaded well (> 0.4) into the assigned subscale and revealed two distinct subscales: cosmesis and function. Based on clinical validity, item “breast shape” was replaced by “breast elevation/position” and “overall skin appearance”. Very good clinical validity (Cohen’s d = 1.38) was found for the new Dutch BCTOS-13. Correlation to the EORTC QLQ-BR23 subscales was high (ICC = 0.65–0.85) for both subscales. Test-retest reliability (Cohen’s d = 0.105) and internal consistency (Cronbach’s α =0.90) were excellent.ConclusionsPsychometric evaluation of a newly developed Dutch BCTOS-13 questionnaire in BCT patients showed excellent results, that were slightly better than the original BCTOS-22 and the shortened BCTOS-12. The good clinical validity makes the BCTOS-13 a useful tool to identify patients with unfavourable cosmetic and functional outcomes, requiring specific attention.Electronic supplementary materialThe online version of this article (10.1186/s41687-018-0085-y) contains supplementary material, which is available to authorized users.
“…The condensation of the former BCTOS into the BCTOS-12 can be found in Fig. 1 and is discussed in further detail in Hennigs et al 2018 [5]. Fig.…”
Section: Resultsmentioning
confidence: 92%
“…Therefore, for the resulting factor scores, which are in the original BCTOS version calculated by the mean of the items corresponding to the respective sub-scores, higher score values indicate worse outcome. Practical experiences during years of using the BCTOS made us believe that the BCTOS should be revised [5]. In detail, some of the 22 individual items of the BCTOS seem to be redundant with respect to both wording and discriminatory power, especially for items regarding functional aspects.…”
Section: Methodsmentioning
confidence: 99%
“…The process of refining the BCTOS was performed together with physicians from the Department of Gynecology and Obstetrics of the University of Heidelberg. It was based on an a retrospectively recruited test data set (collected between 2007 and 2012), consisting of the data of 871 patients who underwent breast conservation therapy [5]. In addition, we prospectively collected a validation data set comprising the refined version of the BCTOS consisting of 203 patients recruited between June 2017 and May 2018.…”
Section: Methodsmentioning
confidence: 99%
“…As this is a task which goes far beyond the specific goal to refine the BCTOS the aim of this article is to give an insight in our experiences and methodological choices we made during this refinement process. The first steps can already be found in Hennigs et al [5]. However, the results presented in that paper are more focused on medical aspects and ended with yielding a new item factor structure.…”
Background
Patient Reported Outcomes (PRO) are gaining more and more importance in the context of clinical trials. The assessment of PRO is frequently performed by questionnaires where the multiple items of a questionnaire are usually pooled within summarizing scores. These scores are used as variables to measure subjective aspects of treatments and diseases. In clinical research, the calculation of these scores is mostly kept very simple, e.g. by a simple summation of item values. In the medical literature, there is hardly any guidance for performing a refinements of questionnaires and for deducing adequate scores. In contrast, in psychometric literature, there are plenty of more sophisticated methods, which overcome typical assumptions made in traditional (sum) scores, however to the prize of more complicated algorithms, which might be difficult to communicate. When faced with the practical task to refine an existing questionnaire, there exist a clear gap of guidance for applied medical researchers. By this article we try to fill this important gap between psychometric theory and medical application by illustrating our methodological choices on the example of a clinical PRO questionnaire.
Methods
Based on our experiences with the refinement of the BCTOS, a PRO questionnaire to assess aesthetic and function after breast conserving therapy in breast cancer patients, we present the following general steps that we performed by refining the BCTOS questionnaire and its scores: 1. Refinement of the length of the questionnaire and the (item-factor) structure. 2. Selection of the factor score estimation method. 3. Validation of the refined questionnaire and scores with respect to validity, reliability and structure based on a validation cohort.
Results
Our step-step-step procedure helped us to shorten the current form of the BCTOS and to redefine the factor structure. By this, the compliance of patients can be increased and the interpretation of the results becomes more coherent.
Conclusions
We present a step-by-step procedure to refine an existing medical questionnaire along with its scores illustrated and discussed by the refinement of the BCTOS.
Trial registration
Due to the character of the study (no intervention study), no registration was performed.
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