Introduction

Most children with cancer survive [1], in part, related to the administration of intensive therapies. However, these treatments result in severe and bothersome symptoms for the majority of children [2]. In a prior study of 302 inpatients, nearly all (98.7%) reported having at least one symptom of any degree of bother (score ≥ 1 on a 0 to 4 scale) and 181 (59.9%) had at least one symptom scored as “a lot bothered” or “extremely bothered” (score of 3 or 4) at enrollment [3]. We found that changes in taste was the third most common symptom of any degree of bother (182/302, 60.3%) and also the third most common severely bothersome symptom (43/302, 14.2%) [2]. That study enrolled children without cancer undergoing hematopoietic stem cell transplantation (HSCT) because conditioning regimens include intensive chemotherapy expected to result in severe symptoms.

Changes in taste can include dysgeusia (abnormal taste), hypogeusia (diminished taste) or ageusia (complete lack of taste sensation) [4]. In adult cancer patients, changes in taste has been associated with reduced food enjoyment [5]. In this population, studies have documented a high prevalence of distress and impact on daily life associated with taste changes [6]. A relationship between taste disorders and decreased caloric intake has been observed [7], resulting in weight loss [6] and vitamin deficiencies [8].

However, much less is known about how pediatric cancer patients experience changes in taste, nor is much known about the strategies they use to manage the symptom. This symptom is important in pediatric cancer not only because of its prevalence and degree of bother, but also because it may have other consequences. In one qualitative study of 22 children with cancer-receiving chemotherapy, altered taste was considered the main reason for eating difficulties [9]. Consequently, the objective was to describe how children receiving cancer treatments experience taste alterations, and the approaches they use to cope with the issue.

Materials and methods

This qualitative study consisted of a single semi-structured interview. The study was approved by the Research Ethics Board at The Hospital for Sick Children and all participants and their guardians provided informed consent or assent as appropriate.

Subjects

We included English-speaking children 4–18 years of age with cancer or hematopoietic stem cell transplantation (HSCT) recipients who were actively receiving cancer treatment or who had completed therapy within any time frame. We excluded those whose illness severity, cognitive disability or visual impairment precluded utilization of SSPedi or mini-SSPedi according to the primary healthcare team.

Procedures

Potential respondents were approached in the inpatient or outpatient setting. Sampling was consecutive and, given expected differences by age, we enrolled patients into the following age cohorts: 4–7, 8–10, 11–14 and 15–18 years. Demographic information was obtained from the respondent, respondent’s guardian and from the patient’s health record. Additional data collection was decided a priori based upon previous literature and included the following: receipt of cisplatin [10] or vincristine [11] in the 3 months prior to interview, head and neck radiation [12] and HSCT [13]. Based upon our previous study [14], we also asked about current mouth sores or mucositis and presence of nausea or vomiting in the previous 7 days (both recorded as none, mild, moderate or severe). For those who had completed treatment, we recorded time from the last treatment.

Interviews were conducted in person by trained research personnel. First, participants completed a paper version of Symptom Screening in Pediatrics Tool (SSPedi) (age 8–18) [3] or mini-SSPedi (age 4–7) [15]. Both measures include 15 symptoms and ask children to indicate how much each symptom bothered them. SSPedi has a recall period of yesterday or today and uses a 5-point Likert scale while mini-SSPedi has a recall period of today and a 3-point Likert scale to account for developmental differences between the age groups. SSPedi is reliable, valid and responsive to change [3]. Mini-SSPedi is understandable and easy to complete for children 4–7 years of age [15]. Then, using a semi-structured questionnaire (Online Resource 1), we asked each patient about their experience with altered taste sensation. We asked about its characteristics, impacts and identified coping strategies. In this study, coping was defined as strategies used by children to either reduce taste changes or to make them less bothersome. Parents and guardians were not specifically probed but if they provided comments, these were noted and included in the analysis. The interview was audio-recorded and transcribed.

Analysis

Qualitative interview data were analyzed using the constant comparative technique derived from grounded theory methods [16]. Data were coded into common categories based on similar content by two investigators working independently; in other words, all transcripts were double coded. Any new categories that emerged during the process were compared with previous categories. The investigators then translated codes into higher level categories by analyzing and grouping similar codes into broader conceptual categories, using the constant comparative method, eventually reducing these categories into a set of higher level themes [17]. Where coding was discrepant, a third team member was consulted. A total of 10 meetings were required before finalizing the code book. We planned to enroll 10 to 30 participants in each of the four age groups and enrolled patients in groups of five until saturation was achieved per age category, defined as no new themes identified in a round of five interviews [18].

Results

Figure 1 illustrates the flow diagram of patient identification and selection. In total, 73 children were assessed for eligibility, 14 did not meet eligibility and nine declined participation, thus leaving 50 who were interviewed when saturation was reached in each age category. The number in each age group were: 4–7 years (n = 10), 8–10 years (n = 15), 11–14 years (n = 15) and 15–18 years (n = 10).

Fig. 1
figure 1

Flow diagram of child identification and enrollment

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Table 1 describes the demographics of the 50 participants; 33 (66%) were male. Of the nine patients who had received radiation, seven received radiation therapy specifically to the head and neck region (not as part of total body irradiation). In terms of exposure to specific chemotherapy in the previous 3 months, three (6%) had received cisplatin and 26 (52%) had received vincristine. The SSPedi scores of the 40 participants 8–18 years of age indicated that 16 (40%) experienced changes in taste that were mildly to severely bothersome and, of these, seven (18%) described severely bothersome changes in taste on the day of the interview or the day before. Among the 10 children aged 4–7 years, two (20%) described bothersome changes in taste using mini-SSPedi on the day of the interview.

Table 1 Demographics of the study Cohort (N = 50)
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Table 2 describes the patients’ experiences with changes in taste (Fig. 2). The number of times each theme was identified is indicated in the table. Heterogeneous experiences were described although the most common experience was that food tasted “different”, “not right” or “funny”. Some noted that food tasted blander but others noted that flavors were more extreme than before cancer treatment or HSCT. Food tasting metallic, bitter or sour were specifically noted. While change in food preferences due to taste alteration was common, alternative food choices varied.

Table 2 Experience of changes in taste
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Fig. 2
figure 2

General themes observed in changes in taste

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Table 3 identifies cancer treatments and symptoms that patients associated with changes in taste. While medications in general were noted to be associated with changes in taste, dexamethasone specifically was noted to make food taste better.

Table 3 Associations with changes in taste
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Table 4 describes themes related to timing of changes in taste, which also were relatively heterogeneous with some describing fluctuations in the symptom while others described the symptom being more constant. One participant noted that changes in taste started before treatment began while many noted it started with treatment initiation or during treatment. In terms of timing of resolution, of the 12 patients who had completed treatment who had experienced changes in taste at any point, three described that it resolved after treatment completion. The remaining nine patients off treatment continued to experience changes in taste at the time of the interviews, conducted as distally as 5 months following HSCT and 9 months following chemotherapy completion. A further three patients receiving active therapy for relapsed disease at the time of the interview noted symptom resolution upon initial completion of treatment. Five other patients reported that changes in taste resolved while receiving active treatment.

Table 4 Timing of changes in taste
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Approaches used to manage changes in taste are described in Table 5. Specific interventions included sucking on candy and brushing teeth. Other interventions focused on trying different food or specific food choices.

Table 5 Approaches to management of changes in taste
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Discussion

In this qualitative study, we described the experience of changes in taste from the perspective of children receiving cancer treatments. Children experienced this symptom in a heterogeneous fashion although commonly described food as tasting “different”, “not right” or “funny”. While change in food preferences due to taste alterations was common, specific food choices varied. Many children found changes started with treatment initiation or mid-way through treatment and, for some, persisted up to 9 months following treatment completion. Actions taken by children to address taste changes included sucking on candy, brushing teeth and modifying food choices.

Much more is known about changes in taste in adults compared to children [5, 19]. Dysgeusia is highly prevalent in adults with cancer, with estimates ranging from 38 [20] to 66% [6]. In adults with head and neck cancer undergoing radiotherapy, changes in the ability to taste sweet, salty, sour and bitter were documented following radiotherapy with impairment mainly with tasting of salt and bitter [21]. In contrast to this report, children with cancer and HSCT recipients do not appear to experience just a diminishment of taste sensation but also reported heightened or exaggerated taste sensation.

Coping strategies described among adult patients included frequent oral hygiene, systematic testing of foods and acceptance of change [22]. While use of candy has been described as a coping strategy in adults [23, 24], its use was prominent in our study. Our study also suggested that changes in taste did not always resolve soon after completion of treatment. This finding is in contrast to those described in adult patients where abnormalities in taste typically resolve 3 months after completion of chemotherapy [25].

The mechanism of changes in taste is not clear. In a study that evaluated sweet, bitter or salt tastes among 11 children with acute leukemia undergoing transplantation compared to 20 healthy children, only minor changes in taste thresholds were demonstrated [26]. The authors concluded that alterations in taste thresholds do not account for changes in taste reported by patients. However, a second study suggested more taste alterations compared to healthy controls with higher thresholds for bitter and more taste-recognition errors [9].

The strengths of our study are its focus on an understudied but important issue in pediatric cancer patients and its qualitative design, which allowed initial exploration of the issue. However, our findings must be interpreted in light of their limitations. These include conduct of the study at a single center and only among English-speaking participants, which reduce the generalizability of our results. It is possible that experiences with taste changes differs in other regions and among different non-English speaking cultures. Another limitation is that we did not specifically probe guardians for their input and they may have provided additional important information had this occurred. However, we did include their comments when spontaneously provided, which may also be another limitation since they may not have reflected the opinions of their child.

Future efforts should determine the association between specific changes in taste and specific treatments, the consequences of changes of taste and whether the experience differs in different populations. It will also be important to determine if implementation of systematic symptom screening and development of a clinical practice guideline for taste changes can reduce its impact and improve patient quality of life. Finally, this work could lead to the development of a scale to measure changes in taste, which would allow identification of patients at higher risk of taste changes. These studies would need to include a control group.

In conclusion, the experience of changes in taste is common yet is highly variable in its presentation and resultant changes in food preferences. Taste changes did not always resolve soon after treatment completion. Actions taken to address taste changes were sucking on candy, brushing teeth and modifying food choices. Future research should identify ways to manage this symptom in pediatric cancer patients.