Study Design and Setting

This randomized controlled trial was conducted between June 2022 and May 2023 at the chemotherapy center of a private hospital in Kocaeli, in western Turkiye. Permission was obtained from the authors via e-mail to use the Edmonton Symptom Assessment Scale (ESAS) and the EQ-5D Quality of Life Scale for this research. Ethical approval was obtained from the Marmara University Faculty of Medicine Clinical Research Ethics Committee (no: 09.2021.616, date: 2 July 2021). In addition, written institutional approval was obtained from the private hospital where the research was conducted. Informed consent was obtained from all patients.

The study was conducted in accordance with the Declaration of Helsinki and the Law on Medical Research Involving Human Subjects and was registered in the US Clinical Trials Registry (ID No: NCT05825287).

The study population consisted of patients diagnosed with cancer for the first time (lung, breast, gastrointestinal, genitourinary, and head and neck cancers, skin tumors, and soft tissue tumors).

Participants and Sample

The sample size was calculated by power analysis using the G*Power (v3.1.7) program based on Cohen’s effect size coefficient [11]. To exceed 95% power with a significance level of 5% and effect size of 0.5, the necessary sample number was determined as 70 patients (35 per group). To account for potential losses during the study, we recruited a total of 80 patients, 40 in each group. All patients assigned to the intervention and control groups completed the study.

Inclusion and Exclusion Criteria

Patients who were over 18 years of age, were receiving chemotherapy for the first time, received intravenous and oral chemotherapy, spoke Turkish, and volunteered to participate in the study were included. Patients who received radiotherapy in addition to chemotherapy or had any communication problems or cognitive impairment were excluded.

Randomization

Patients who met the inclusion criteria were assigned to one of the groups using a random number generator (https://randomizer.org). Participants in the intervention group received patient education delivered using the teach-back method, while those in the control group received standard patient education.

Study Variables

The independent variables of the study included age, gender, education level, occupation, income level, marital status, chronic disease status, and type of patient education received. Dependent variables were symptoms experienced (e.g., nausea, vomiting, pain, infection, diarrhea, constipation, difficulty swallowing, fatigue, hair loss, skin and nail changes, sleep disturbance, psychological problems) and quality of life.

Data Collection ToolsParticipant Information Form

This form was created by the researchers and consisted of a total of 18 questions including the patient’s age, gender, marital status, smoking and alcohol use, employment, education level, chronic diseases, and previous knowledge about chemotherapy.

Edmonton Symptom Assessment Scale

This scale, developed by Bruera et al. [12], includes items evaluating eight symptoms common among cancer patients (pain, fatigue, nausea, sadness, anxiety, sleepiness, loss of appetite, and shortness of breath), as well as an item assessing well-being and a final item for other problems that can be specified by the patient.

The validity and reliability study of the ESAS in Turkiye was carried out by Yeşilbalkan et al. [13]. Another study was conducted by Kurt and Unsar [14]. The ETS was shown to be a valid and reliable scale. Based on the literature, Kurt and Unsar added three additional symptoms often seen in patients (skin and nail changes, oral wounds, and hand numbness) to the “other problems” section of the scale. Patients rate the severity of each symptom from 0 to 10. A score of 0 indicates that the symptom is absent, and a score of 10 indicates that the symptom is at its most severe. The highest score that can be obtained from the Turkish version of the scale is 120 points.

EQ-5D Quality of Life Scale

The EQ-5D is a general health-related Quality Of Life Scale developed by the EuroQoL group [15]. It consists of five dimensions: mobility, self-care, pain/discomfort, anxiety/depression, and daily activities. In the 3L version, each dimension is rated on three levels, “no difficulty,” “moderate difficulty,” and “extreme difficulty,” with higher scores indicating poorer quality of life. Each of the scale dimensions yields a score ranging from − 0.59 to 1. Negative values indicate states such as immobility and unconsciousness, a score of 0 indicates death, and a value of 1 indicates perfect health. The scale also includes a visual analog scale (VAS) on which the individual rates their perceived general health status between 0 and 100. The scale was found to be valid and reliable for use in Turkiye by Kahyaoğlu Süt and Ünsar [16].

Data Collection

In hospitals, educational materials are generally used to explain the adverse effects that patients receiving chemotherapy treatment may experience and methods of coping with them. In this study, a “Chemotherapy Education Booklet” based on the teach-back method was prepared by the researchers to be used in the training of the intervention group. The booklet was presented to 14 experts and statistically evaluated with the DISCERN scale. The DISCERN total score average was found to be 69.07, indicating the quality of the booklet was excellent. The control group was provided education using “The A-to-Z Chemotherapy Guide”, which was updated in 2021 by the institution’s Patient Education Board in March 2021 and is currently used for standard patient education in the hospital. After both groups received patient education, data were obtained by administering the ESAS and EQ-5D Quality of Life Scale. The results were analyzed to compare the effectiveness of the education.

The first session of patient education was held 30 min before receiving chemotherapy for the first time. Education sessions were repeated in both the intervention and control groups on days 14, 21, and 28, on which they were scheduled to receive chemotherapy. All sessions were conducted by the researcher in individual face-to-face meetings held in the patient education room, and each education session was also attended by the chemotherapy case manager. Education sessions lasted 20 min on average for patients in the control group and 30 min on average for those in the intervention group.

On the fifth day after each education/chemotherapy session (on days 6, 19, 26, and 33), patients were contacted by phone to administer the EQ-5D and ESAS again.

Table 1 shows the stages of the research, including data collection, education, and counseling. The CONSORT flow chart of the study is given in Fig. 1.

Table 1 Data collection, education, and counseling performed in the studyFig. 1

CONSORT flow diagram of the study

Outcomes

The primary outcomes of the study were symptom management and quality of life after chemotherapy.

Blinding

Double blinding was not possible in this study because the researcher applied the intervention. However, since the participants did not know their group assignment, single-blinding was achieved. Moreover, data analysis was performed by an external biostatistics specialist, resulting in blinding during the analysis phase.

Statistical Analysis

The demographic and clinical characteristics of the patients in the study were summarized using number and frequency values. ESAS and EQ-5D scores were summarized using mean and standard deviation. Parametric tests were used for statistical analysis because there were more than 30 participants in each group [17,18,19]. The groups were compared with the chi-square test, Fisher’s test, and independent-samples t-test. Comparisons of the data within groups were performed using repeated measures analysis of variance (ANOVA). For this test, the Greenhouse–Geisser correction was applied if the results of Mauchly’s test of sphericity indicated non-homogeneous variances. The paired-samples t-test with the Bonferroni correction was used for multiple comparisons of variables that differed within a group. Statistical significance was accepted at p < 0.05 in all analyses. The data were analyzed using the IBM SPSS Statistics version 27 statistical package program.