A Hidden Weakness in Oral Cancer Treatment: Self-Care Capacity May Determine Whether Patients Take Their Medicines Correctly
Cancer treatment is increasingly moving from the infusion room to the patient’s home, but a new study suggests that this shift may carry an overlooked risk. Among 140 adults receiving oral chemotherapy in Türkiye, nearly four in five failed to meet a threshold for good medication adherence. The research found that patients’ ability to organize and perform their own health care—described by researchers as “self-care agency”—was moderately associated with how consistently they took their cancer medicines, monitored symptoms, attended follow-up appointments and communicated with medical staff. The findings point to a challenge that is easy to miss when treatment is delivered as tablets rather than through a hospital-based infusion: the therapy may be pharmacologically powerful, but its success also depends on whether patients can manage a complicated daily regimen under real-world conditions. The study, published in Supportive Care in Cancer, does not show that low self-care directly causes missed doses, but it identifies a potentially important pathway linking social circumstances, self-management and adherence.
Oral chemotherapy includes conventional cytotoxic drugs as well as targeted and other systemic medicines taken by mouth. Unlike intravenous treatment, in which clinicians administer each dose and can observe much of the process, oral treatment transfers many responsibilities to the patient. A person may need to remember a precise schedule, understand whether a pill should be taken with food, store it correctly, recognize adverse effects, avoid unsafe interactions and know when to contact the oncology team. Some medicines are taken in cycles, while others follow continuous daily schedules; doses may change when blood counts, liver function or symptoms change. Side effects such as nausea, fatigue, diarrhea, pain or cognitive difficulties can make the routine harder to sustain. The apparent simplicity of swallowing a tablet can therefore conceal a complex behavioral and clinical task. Missed doses, incorrect timing or premature discontinuation can alter drug exposure, potentially reducing treatment effectiveness, while taking extra doses can increase toxicity.
The investigators assessed participants using two standardized instruments: the Self-Care Agency Scale, or SCAS, and the Oral Chemotherapy Adherence Scale, or OCAS. Self-care agency refers to a person’s perceived capacity to identify health needs, make decisions, acquire relevant skills and carry out actions that maintain or improve health. It is not identical to motivation, intelligence or compliance. Rather, it represents a functional combination of knowledge, confidence, attention, planning and practical ability. The study also collected information on age, gender, education, income, comorbidities, treatment duration and side-effect burden. These variables were treated as “basic conditioning factors”—characteristics that can shape the resources and demands involved in self-care. The researchers then used correlations and a theory-specified observed-variable mediation path model to examine whether self-care agency could statistically connect these background factors with three dimensions of oral chemotherapy adherence.
The average SCAS score was 56.78, with a standard deviation of 17.42. Because the possible scale range ran from 0 to 140, the average fell below the midpoint, suggesting that many participants reported limited self-care capacity relative to the instrument’s full range. The average OCAS score was 77.92, with a standard deviation of 10.71. According to the scale’s developer-defined threshold, a score of 84 or higher represents good adherence. On that basis, 78.6 percent of participants had suboptimal adherence, while only 21.4 percent reached the good-adherence threshold. These classifications should not be interpreted as proof that patients were deliberately ignoring medical instructions. A questionnaire score can reflect difficulties with memory, understanding, symptom control, access to care, financial pressure or the demands of treatment. Nevertheless, the results reveal a substantial gap between prescribing an oral anticancer drug and ensuring that it is used safely and consistently.
The strongest central finding was a moderate positive relationship between self-care agency and oral chemotherapy adherence. The total SCAS and OCAS scores were correlated at r = 0.43, with p < 0.001. In practical terms, participants who reported greater capacity for self-management also tended to report better adherence. The correlation is neither weak nor so large that it could explain adherence on its own. Medication-taking behavior is influenced by many interacting factors, including regimen complexity, side effects, beliefs about treatment, depression, social support, health literacy, transportation, cost and the quality of communication with clinicians. A correlation also does not establish direction: stronger self-care might support adherence, but successful treatment routines could alternatively build confidence and improve self-care scores. The study’s cross-sectional design, in which information was collected at one point in time, cannot resolve that question.
The path analysis offered a more detailed statistical picture. In the model, self-care agency significantly predicted all three adherence subdimensions, with standardized beta coefficients ranging from 0.36 to 0.46; all associations had p values below 0.001. A standardized beta describes the expected change in an outcome, measured in standard-deviation units, associated with a one-standard-deviation change in a predictor while accounting for other variables in the model. The analysis also found positive indirect associations for income and education, and negative indirect associations for older age and female gender, across all three adherence dimensions through self-care agency. The bootstrap 95 percent confidence intervals for these indirect effects excluded zero. Bootstrapping repeatedly resamples the observed data to estimate the uncertainty around an indirect pathway, making fewer assumptions about the distribution of mediation effects. These results suggest that demographic and socioeconomic differences may operate partly through patients’ ability to manage care, rather than acting as isolated predictors of adherence.
The statistical model, however, was not a perfect explanation of the data. The researchers tested 18 omitted direct paths and rejected exact fit, with χ²(18) = 43.96 and p < 0.001. Its approximate-fit indicators were mixed: the comparative fit index was 0.96, the Tucker–Lewis index was 0.89, the root mean square error of approximation was 0.102 and the standardized root mean square residual was 0.037. These measures assess how closely the proposed network of relationships reproduces the observed pattern of correlations, and they should be read together rather than treated as a single pass-or-fail score. The high comparative fit index and low standardized residual were favorable, while the Tucker–Lewis index and especially the RMSEA raised concerns about model misspecification or limited fit. Most importantly, a statistically significant indirect association is not the same as demonstrated causal mediation. The model is consistent with a pathway, but it cannot prove that increasing self-care agency would necessarily improve adherence.
For oncology teams, the findings suggest that adherence support may need to begin before a patient leaves the clinic with a prescription. Education can include more than an explanation of the drug’s name and dose. Nurses and pharmacists might assess whether patients can describe their schedule in their own words, distinguish expected side effects from warning signs, explain what to do after a missed dose and identify whom to contact in an emergency. Written instructions, pill organizers, calendars, reminder systems and telephone or digital follow-up could reduce the cognitive burden of treatment. Yet the study’s equity-related findings warn against assuming that every patient has equal access to these tools. Lower income may restrict transportation, internet access, food security or the ability to take time away from work. Lower educational attainment may make dense written materials less useful, particularly when they contain unfamiliar medical terminology. Support therefore needs to be adapted, repeated and linked to practical resources rather than delivered as a one-time information session.
The researchers acknowledge several limitations that place the results in context. The sample included 140 adults receiving oral chemotherapy in oncology outpatient clinics in Türkiye, so the findings may not apply to every cancer population, health system or medication regimen. The design was descriptive and cross-sectional, and the principal measures were self-reported questionnaires; participants may have forgotten doses or answered in ways they believed were socially acceptable. The analysis also used an observed-variable mediation model rather than a longitudinal design that could track self-care and adherence over time. Future studies could combine pharmacy refill records, electronic medication monitoring, clinical outcomes and repeated assessments of symptoms and self-care. Randomized trials would be needed to determine whether nurse-led education, tailored follow-up or integrated symptom-management programs actually raise adherence and improve outcomes. Even so, the study highlights a clinically important message: oral chemotherapy is not simply intravenous treatment in pill form. Its effectiveness depends on a partnership between drug biology and the patient’s capacity to carry out an intricate plan, and that capacity can be strengthened—or undermined—by the social conditions surrounding care.
Subject of Research: Self-care agency and medication adherence among adults receiving oral chemotherapy for cancer
Subject of Research: Cancer
Article Title: Self-care agency and medication adherence among cancer patients receiving oral chemotherapy: a path analysis study
Article References: Camci, G. B., Berşe, S., Bilici, D., & Cengiz, Z. (2026). Self-care agency and medication adherence among cancer patients receiving oral chemotherapy: a path analysis study. Supportive Care in Cancer, 34(9), Article 904. https://doi.org/10.1007/s00520-026-11142-7
Image Credits: AI Generated
DOI: 10.1007/s00520-026-11142-7
Keywords: oral chemotherapy, self-care agency, medication adherence, cancer patients, oncology nursing, path analysis, health equity, symptom monitoring
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Rowan Blackwood. (August 28, 2026). Study Links Self-Care Agency to Adherence in Oral Cancer Therapy Patients. Scienmag. https://scienmag.com/study-links-self-care-agency-to-adherence-in-oral-cancer-therapy-patients/
Rowan Blackwood. “Study Links Self-Care Agency to Adherence in Oral Cancer Therapy Patients.” Scienmag, 28 August 2026, https://scienmag.com/study-links-self-care-agency-to-adherence-in-oral-cancer-therapy-patients/. Accessed 28 August 2026.
Rowan Blackwood. “Study Links Self-Care Agency to Adherence in Oral Cancer Therapy Patients.” Scienmag. August 28, 2026. https://scienmag.com/study-links-self-care-agency-to-adherence-in-oral-cancer-therapy-patients/
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