Adherence to oral anticancer hormonal therapy in breast cancer patients and its relationship with treatment satisfaction: an important insight from a developing country

We conducted the current multicenter cross-sectional study to assess breast cancer patients' adherence and satisfaction with oral hormonal medications using two main sets of data: medical records (both on paper and electronic) and women breast cancer patients’ interviews. This research was conducted using convenience sampling between November 2021 and January 2022. All patients who came to the hospital for treatment or follow-up care and met the inclusion criteria were asked to complete the questionnaire.

Our research was carried out in the oncology centers of the Al-Watani Hospital and the An-Najah National University Hospital in Nablus, Palestine. These hospitals are the largest and most important referral sites for cancer patients from all locations in Palestine.

According to medical records, the number of women with breast cancer visiting the two hospitals during the study period was approximately 175. Therefore, the recommended sample size was 121 patients using an online calculation, Raosoft, with a response of 50%, a 5% margin of error, and a 95% confidence interval.

This study included women who had survived breast cancer over 18 years of age and had been prescribed and initiated oral hormonal drugs (neoadjuvant or adjuvant) at least four weeks prior to enrollment. Patients with comorbid delirium, dementia, bipolar, substance dependence disorders, untreated psychotic disorders, hospitalized patients, or those who were unable to participate or refused were excluded because of their inability to consent. We also excluded patients with missing findings in their medical records.

Two clinical pharmacists collected the data through face-to-face interviews with patients. Before beginning the data analysis, regular checks were performed for data integrity, proper sequences of information, and an evaluation of missing or incomplete variables.

Questionnaires were completed by explaining the questions to the patients, filling in the information on papers using specific scales to assess cancer patients' adherence and satisfaction, and recording the patients’ sociodemographic information (Table 1). In addition, medical records were used to record information related to disease and treatment characteristics.

The Medication Adherence Rating Scale (MARS) is used to assess adherence to medication [14]. It is a 10-item self-report instrument with yes/no responses to the questions asked, with a summation yielding a maximum of 10 points. MARS scores can range from 0 (low likelihood of adherence) to 10 (high likelihood of adherence). It also has three groups of items: "medication adherence behavior" (questions 1–4), "attitude toward taking medication" (questions 5–8) and "negative side effects and attitudes toward oral hormonal medication" (questions 9, 10). However, three theoretically irrelevant items (questions 5, 7, and 9) were removed due to poor item-total correlation. These excluded items are “I take my medication when I am sick”, “My thoughts are clearer on medication”, and “I feel weird, like a 'zombie', on medication”. Therefore, the maximum point became 7 (high likelihood of adherence).

The Treatment Satisfaction Questionnaire for Medication (TSQM) version 1.4 assesses patients' perceptions of treatment [15‐18]. It evaluates effectiveness (items 1–3), side effects (items 4–8), convenience (items 9–11), and global satisfaction (items 12–14). The TSQM is a validated scale ranging from 0 to 100, with a higher score denoting better satisfaction [19]. The TSQM scale uses 14 questions to evaluate patient satisfaction; questions 1 through 3 inquire about the patient's satisfaction with the drug's efficacy in preventing and treating his disease, as well as the drug's capacity to relieve the patient's symptoms and the length of time it takes to begin working. Questions 4–8 inquire about the drug's adverse effects, the degree to which the patient finds them bothersome, how they affect his bodily and emotional well-being, and how much of an impact they have on the patient's satisfaction with the medication. The ninth and tenth questions concern the ease or difficulty of using the medication and scheduling a time for it to be used, while the eleventh question concerns whether it is proper to take the medication as directed. The confidence of the patient that this medication is helpful to him, that its benefits outweigh its drawbacks, and the degree of his general satisfaction with the medication are evaluated in questions 12 through 14. The Arabic version of the TSQM 1.4 is a valid and reliable instrument for assessing the perceptions of patients about treatment [19]. It has been used in several publications in Palestine [16, 17, 20‐25]. In addition, IQVIA™ has given An-Najah National University permission to utilize this questionnaire in their research.

The pilot study sample consisted of 10 breast cancer patients chosen at the same criteria as the study population. The questionnaire was also completed in the same manner as it was for the study's population. Both scales, TSQM and MARS, were tested in the sample to evaluate the simplicity, understandability, and time to fill out all questions of the questionnaire. The Cronbach's alpha was 0.673 for the effectiveness domain of TSQM, 0.899 for side effects, 0.747 for convenience, and 0.878 for global satisfaction.

Table 1 describes the sociodemographic and clinical characteristics of the 106 women with breast cancer. Of all 121 recruited patients, 15 refused to participate due to lack of time, privacy, and psychological problems. Approximately 53% of the participants were aged between 45–65 years, 39.6% were obese, 67% had no university education, and 84% were unemployed. According to clinical characteristics, most patients had comorbidities and took other chronic drugs (51.9% and 68.9%, respectively). Furthermore, 81.1% of the patients underwent breast surgery, while 80.2% received chemotherapy. The current hormonal therapy among cancer patients is as follows: letrozole 38.7%, tamoxifen 31.1%, exemestane 17%, and anastrozole 13.2% (Table 1).

Among 106 women with breast cancer, the median adherence score was 5.0 [4.8–6.0] (range: 1.0–7.0). Approximately 62.3% of the patients reported a high likelihood of adherence to oral hormonal drugs in the past week. Regarding the associations between patient characteristics and adherence score, a significantly lower adherence score was identified in patients living in camps (p = 0.020). Patients with comorbidities and those who continued on the same hormonal therapy had higher adherence scores, although they were not statistically significant. In this study, patients with comorbidities had a mean rank of 58.18, with a median of 5.0 [5.0–6.0], while patients without comorbidities had a mean rank of 48.45, with a median of 5.0 [4.0–6.0]. In terms of hormonal drug switching, the mean rank of patients who switched to another hormone therapy was 45.18, with a median of 5.0 [4.5–6.0], while the mean rank of patients who continued with the same hormonal prescription was 56.78, with a median of 5.0 [4.5–6.0] (Table 2).

As shown in Table 3, there were significant correlations between MARS score and treatment satisfaction, including side effects (p = 0.024) and global satisfaction (p = 0.008). Women with a high adherence rate had higher satisfaction scores than women with a low adherence rate. Spearman’s rank order correlation coefficient between MARS adherence score and side effects and global satisfaction TSQM scores indicated significant positive correlations (r = 0.220 and 0.258, respectively).

As shown in Table 4, the TSQM score assesses perceived effectiveness, side effects, convenience, and global satisfaction. The median score of each domain was 66.67 [61.11.0–72.22], 75.00 [48.44–100.00], 66.67 [66.67–72.22], and 71.43 [57.14–78.57], respectively. Postmenopausal patients had significantly higher satisfaction towards side effects (p = 0.049). In addition, patients with comorbidities had a higher global satisfaction score (p = 0.010). Furthermore, the satisfaction score toward side effects was significantly lower in patients with experienced side effects (p = 0.001) and those hospitalized in the last year (p = 0.030). Moreover, letrozole therapy was significantly associated with higher satisfaction with perceived effectiveness (p = 0.002) and global satisfaction (p = 0.004).

From the univariate analysis, residency, side effects, and global satisfaction were found to be statistically significant (p < 0.05). Multiple linear regression analysis revealed that the side effects domain (p = 0.013) and global satisfaction (p = 0.018) were predictors of oral hormonal drug adherence (Table 5).