Introduction

Cancer patients suffer from many physical and psychosocial problems that require early detection and treatment, regardless of curability of the disease or disease stage [1]. The EORTC Core Quality of Life Questionnaire (QLQ-C30) is one of the most commonly used, validated and translated questionnaires to assess symptoms and quality of life in cancer patients [2,3,4]. It can be supplemented by disease-specific modules [2]. An abbreviated version of this questionnaire, the EORTC Quality of Life Questionnaire Core 15 Palliative Care (QLQ-C15-PAL), was developed for patients in palliative care [5] and has also been successfully validated in several countries [6,7,8,9]. However, static questionnaires with closed questions cannot be expected to cover all symptoms/problems experienced by cancer patients and therefore, the use of open-ended questions supplementing these questionnaires may facilitate the recognition of symptoms and toxicities [10].

A brief supplementary instrument named WISP (Write In three Symptoms/Problems) was developed in Denmark for use alongside the QLQ-C15-PAL. This is an open-ended question allowing patients to report and rate the severity of up to three additional symptoms/problems not included in the QLQ-C15-PAL [11]. The first study published on WISP showed that a third (33%) of the 5,447 patients answering the QLQ-C15-PAL at admittance to Danish specialist palliative care in 2016 reported at least one symptom/problem using WISP, totally 2,796 symptoms/problems added via WISP. Of these, 64% were not covered by the QLQ-C15-PAL, 25% were already covered and 11% were diagnoses or responses that could not be coded [11]. These findings demonstrate that adding WISP to the original QLQ-C15-PAL improves the recognition of symptoms/problems not measured by this questionnaire.

To evaluate the acceptability and usefulness of WISP to cancer patients in general (not just those receiving palliative treatments), we conducted a cross-sectional study involving patients receiving both active and palliative care/treatment from European and non-European countries.

Methods

This study was conducted in three steps: 1) literature search on validated instruments using open-ended questions in cancer patients, 2) translations of WISP following the EORTC Quality of Life Group (QLG) Translation Procedure [12] and 3) pre-testing the translated WISP alongside the EORTC questionnaires and expanding the qualitative part with structured patient interviews to identify potential comprehension problems, following the EORTC QLG Module Development Guidelines (Phase 3.a) [13]. These steps are described in further detail below.

Literature search

We performed a literature search on validated instruments with open-ended questions for cancer populations since 1990. The following keywords were searched in PubMed and CINAHL in March–April 2020: (("Patient-reported outcomes" OR "Patient-reported outcome measurements" [MeSH] OR "EORTC-QLQ" OR "systematic assessment") AND (open-ended)) AND ("Terminally ill" [MeSH] OR "advanced cancer" OR "Neoplasms" [MeSH])). When instruments were identified, we contacted the corresponding authors to ask about their experience collecting data with open-ended questions and which coding system they used.

We also contacted all EORTC QLG members asking whether they had knowledge of instruments including open-ended questions used in cancer patients and/or experience performing data analysis for these instruments.

Study population

For the pre-testing of WISP, we planned to recruit cancer patients from at least 6 countries (at least one English-speaking country and one non-European language country) to assess the WISP instrument in a cross-cultural context [13]. In each included country, we planned to recruit 20 patients receiving diverse cancer treatments; 10 patients should be from an oncology setting (5 patients receiving chemotherapy/radiotherapy and 5 receiving immune/targeted treatment in hospital departments), and 10 patients from a palliative care setting (i.e., receiving palliative care/treatment in a palliative care service, hospice or hospital department).

Inclusion criteria were: 1) having knowledge of the cancer diagnosis, 2) being at least 18 years old, 3) undergoing active antineoplastic treatment or palliative care/treatment, 4) being a native speaker of the country's language, 5) being mentally and physically able to participate, and 6) providing informed consent.

Translation

The EORTC QLG Translation Unit made forward/backward translations of the original WISP in Danish into English (Fig. 1) and seven additional languages for cultural adaptation. These translated versions of WISP were pilot-tested in each country by asking five cancer patients in active or palliative treatment to review the wording of the instrument and discuss whether the translated version was difficult to answer, confusing or upsetting [12].

Fig. 1
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English version of the WISP instrument

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Procedure for the pre-testing of WISP and patient interviews

From November 2022 to June 2023, we pre-tested WISP together with the selected EORTC questionnaires. Patients in active treatment completed the QLQ-C30 + a relevant module according to the patient’s diagnosis if available + WISP, whereas patients in palliative care/treatment completed the QLQ-C15-PAL + WISP.

After patients completed the questionnaires and reported at least 1 symptom/problem using WISP, they were invited to participate in semi-structured interviews to collect information on their understanding and acceptability of WISP, as well as the usefulness of WISP for their reporting of ‘additional symptoms/problems not included in the questionnaire they just completed’ [13]. The interviews were conducted in person by local researchers in the patients' native language, were summarized by the local researcher and not audiotaped, and lasted approximately 15–20 min.

Questionnaires

The QLQ-C30 comprises 30 items distributed in five functional scales (physical, emotional, role, cognitive and social functioning); three symptom scales (fatigue, pain, nausea/vomiting); two global scales (global health and quality of life) and six single items (insomnia, dyspnea, constipation, lack of appetite, financial difficulties and diarrhea) [4]. The QLQ-C15-PAL consists of half of the items of the QLQ-C30 containing only those items that are most relevant for patients in palliative care [5]. In both EORTC questionnaires (+ module), items are rated on 4-point Likert scales that range from 1 (not at all), 2 (a little), 3 (quite a bit) to 4 (very much), except for global health/quality of life scales rated from 1 (very poor) to 7 (excellent) [4, 5].

WISP consists of a single item asking patients to report up to three symptoms/problems not mentioned in the questionnaire preceding it (i.e., QLQ-C15-PAL or QLQ-C30 + module). Responses on WISP use the same 4-point rating scale as the EORTC questionnaires [11]. This study only reports data collected on WISP.

Statistical analyses

Patient characteristics were expressed as proportions and compared between patients in active and palliative care/treatment using Chi-square tests (significance level of 0.05).

Qualitative responses from patient interviews were categorized and summarized according to patient treatments. We calculated the proportion of patients adding information about their symptoms/problems and the proportion of patients rating WISP as difficult, annoying, confusing or upsetting to answer.

WISP responses that were rated at least as 2 (a little) were coded using a coding system of 61 symptom/problem categories developed in Denmark to analyze WISP data reported by patients in specialized palliative care [11, 14, 15]. This coding system was developed by grouping the WISP qualitative responses into categories; for example, ‘back pain’ was coded as ‘pain’. If a symptom/problem was not covered by the QLQ-C15-PAL, new codes were established using a list of 48 physical and psychological symptoms developed by Homsi et al., which investigated symptoms reported by palliative patients using open-ended questions versus those systematically assessed [16]. We created extra codes if a symptom/problem did not match any existing category [11]. The prevalence of symptoms/problems reported on WISP was calculated for all cancer patients and for patients receiving different types of treatment (active treatment vs. palliative care/treatment). We calculated the severity as the proportion of symptoms/problems rated as ‘a little’ (mild), ‘quite a bit’ (moderate) and ‘very much’ (severe). Statistical analyses were conducted using the IBM SPSS Statistics 28.

Results

Literature search

A total of 35 studies were identified in the literature search (i.e., 25 in PubMed, and10 in CINAHL) and eight studies were suggested by the EORTC QLG members. Based on these results, we identified seven instruments validated in cancer patients that included open-ended questions in their design, but the studies did not include data collected in the open-ended questions.

From June to July 2020, we contacted the corresponding authors of the Edmonton Symptom Assessment System (ESAS) [17], the Memorial Symptom Assessment Scale (MSAS) [18] and its Short Form MSAS-SF [19], the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) [20, 21], the EORTC Quality of Life Questionnaire—Lung Cancer Module (QLQ-LC29) [22], the Integrated Palliative care Outcome Scale (IPOS) [23] and the EORTC Quality of Life Questionnaire—Breast Cancer Module (QLQ-BR45) [24].

The authors’ responses showed that a small number of them have collected data from the open-ended questions, but the only analysis and publication was the free text collected from the PRO-CTCAE on the reporting of symptomatic adverse events in three cancer clinical trials [21]. For further details, see Supplementary Table 1.

Study population

In total 161 cancer patients from 8 countries (Austria, Chile, France, Jordan, the Netherlands, Norway, Spain and the United Kingdom) completed the WISP instrument and were included in this study. Comparisons of background characteristics between patients in active treatment (n = 80) and palliative care/treatment (n = 81) showed that the distribution of their characteristics was not significantly different, except for diagnosis, type of service and current treatment. The most frequent diagnoses among patients in active treatment were lung and breast cancer and these patients were generally treated with chemotherapy in an oncology department at hospitals, whereas the most frequent diagnosis for patients in palliative care/treatment was cancer in the digestive system, and most received symptom control in palliative care services (Table 1).

Table 1 Sociodemographic and clinical characteristics of 161 cancer patients included in the study
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Patient interviews

Table 2 summarize the qualitative answers obtained from patient interviews. Overall, WISP was widely accepted as less than 2% of the patients had difficulties answering WISP or found it annoying or upsetting. Only a few palliative care patients (n = 5) commented that they were confused about what type of symptoms they should report using WISP (i.e., physical, psychological, etc.). Among the 27 patients who provided additional comments on WISP (question 7), 8 expressed positive opinions on the usefulness and relevance of WISP for reporting their symptoms/problems not covered by the EORTC questionnaires. Most patients believed that the symptoms/problems they reported on WISP were a consequence of their cancer treatment or the disease itself (75.8%).

Table 2 Summary of patient interviews
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Prevalence and severity of symptoms and problems reported on WISP

In total 327 symptoms/problems were reported using the WISP instrument by the 161 cancer patients. Of these, 60.6% were symptoms/problems not covered by the selected EORTC questionnaires, 29.7% were symptoms/problems already covered by the questionnaires and 9.8% were responses coded as diagnoses (Fig. 2). The most frequent diagnoses listed on WISP were mucus (25.0%), infection (9.4%) and respiratory diseases (9.4%) (Supplementary Table 2).

Fig. 2
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Classification of symptoms and problems reported on the WISP instrument by 161 cancer patients

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The prevalence of the 295 symptoms/problems covered or not by the selected EORTC questionnaires were grouped into 49 symptom/problem categories and presented for all cancer patients and for patients receiving different types of treatment (Table 3). The most prevalent symptoms/problems not covered by the EORTC questionnaires listed on WISP by all cancer patients were skin problems (16.1%), numbness/tingling (13.7%), dry mouth (9.3%), existential problems (6.2%) and bleeding (5.0%). Skin problems, sore mouth and bleeding were commonly reported by patients in active treatment, whereas dry mouth, numbness/tingling and existential problems were often reported by patients in palliative care/treatment. Pain (19.3%) and impaired emotional function (9.9%) were among the most prevalent symptoms/problems already covered by the EORTC questionnaires. Overall, 78.0% of symptoms/problems were reported as moderate to severe on WISP, where social and speaking problems were among the most severe (Table 4).

Table 3 Prevalence of 295 symptoms and problems (grouped into 49 categories) reported on the WISP instrument by 161 cancer patients. Symptoms and problems already covered by the QLQ-C30 and QLQ-C15-PAL questionnaires are in italic
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Table 4 Frequency and severity of 295 symptoms and problems (grouped into 49 categories) reported on the WISP instrument by 161 cancer patients. Symptoms and problems already covered by the QLQ-C30 and QLQ-C15-PAL questionnaires are in italic
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Discussion

In this study, we evaluated the open-ended WISP instrument with 161 cancer patients (in active and palliative care/treatment) across eight countries. Our main findings were that WISP showed high acceptability during patient interviews, as a low proportion of patients (2%) found that WISP was difficult to answer. Additionally, WISP proved to be useful in identifying many symptoms/problems (n = 198) not covered by the selected EORTC questionnaires.

A total of 327 symptoms/problems were reported using WISP, of which 60.6% were symptoms/problems not covered by the EORTC questionnaires. Among the most prevalent symptoms/problems listed on WISP, skin problems, numbness/tingling, dry mouth, existential problems and bleeding have also previously been reported as frequent symptoms voluntarily reported by advanced cancer patients [11, 16, 25].

We found that the 80 patients in active treatment frequently reported skin problems (17.5%), sore mouth (7.5%) and bleeding (6.3%). The prevalence of skin problems we observed was higher than reported via open-ended questions in other studies (7–14%) by 50 and 69 cancer patients, respectively [26, 27]. This may reflect the fact that not all patients included in those studies were receiving antineoplastic treatment like our patients. Furthermore, the high prevalence of sore mouth and bleeding is in line with the literature showing that these adverse effects are usually reported by patients while receiving chemotherapy and radiotherapy [28, 29].

Patients in palliative care/treatment often reported dry mouth (17.3%), numbness/tingling (14.8%) and existential problems (8.6%). The prevalence of dry mouth and numbness/tingling found in our study was very high compared to the prevalence of dry mouth (1.3%) and numbness/tingling (1.0%) reported earlier by 1,788 palliative care patients using WISP [11] and by 200 palliative patients using an open-ended question before a list of 48 symptoms (1.5% dry mouth; 2.0% numbness/tingling) [16]. Remarkably, our palliative care patients reported existential problems much more frequently than in the previous Danish study using WISP (0.9%) [11]. This difference may reflect that 60% of our palliative patients were also receiving chemotherapy or another combined therapy, and they may have been considering side effects or had more concerns about the future, while palliative patients in the previous study were mainly receiving end of life care [11].

Regarding the symptoms/problems already covered by the EORTC questionnaires, pain (19.3%) and impaired emotional function (9.3%) were among the most prevalent symptoms/problems. This is consistent with previous studies showing that pain is the most common symptom elaborated by cancer patients using open-ended questions, especially when they need to report the location of the pain [16, 25, 27, 30]. The prevalence of impaired emotional function in our study was higher than in the previous studies using WISP (2–3%) [11, 31].

A strength of this study is that we included a diverse sample of cancer patients (i.e., receiving different type of treatments, at different disease stage and from several countries). To our knowledge, WISP is the only open-ended instrument for which experience with coding and analyses of additional symptoms/problems experienced by diverse cancer populations has been reported [11, 31]. Most of the questionnaires with open-ended questions identified in the literature did not have a coding system in place [19, 24] or the answers were barely analyzed [17, 22]. We also confirmed that the previously developed coding system for WISP was efficient, as only two new codes were needed for this study (i.e., sexual problems and low satisfaction with care). However, we know that collecting data using open-ended questions and the work of manually coding responses may be impractical, but this is the first step to provide a brief instrument that can supplement any other EORTC questionnaire to detect those additional symptoms/problems that are important to patients and need to be addressed during the clinician-patient encounter. WISP also has the potential advantage of reducing the burden of patients as compared to completing lengthy questionnaires.

The next steps for the EORTC WISP instrument will be 1) evaluating its usability in clinical trials by collecting relevant symptoms and toxicities experienced by cancer patients, especially in early phase trials when less is known about the potential effects of a cancer treatment and selecting questionnaires/items can be challenging; 2) linking the 63 WISP categories to the 1,060 items in the EORTC Item library to identify missing items and strengthen the WISP coding system based on previous experiences [21, 32], 3) developing a digital solution for WISP with the option of a dropdown list and/or free text, and 4) exploring whether the most frequently reported symptoms/problems on WISP could contribute to the prediction of health outcomes and should be included to static questionnaires.

Conclusions

The EORTC WISP instrument was found to be acceptable and useful for symptom assessment in cancer patients. As anticipated, distinct differences were seen in the reporting of symptom/problems using WISP between patients in active and palliative care/treatment.

This study confirms the utility of WISP to improve the identification of symptoms/problems not assessed by cancer-generic questionnaires. We therefore recommend its use alongside the EORTC questionnaires to achieve a more comprehensive symptom assessment.