ABSTRACTMEDICATION BELIEFS AMONG ADVANCED CANCER PATIENTS RECEIVING ORAL ONCOLYTIC AGENTSByVictoria K. MarshallThe purpose of this dissertation is to examine how medication beliefs among advanced stage cancer patients receiving oral oncolytic agents (OAs) change over the first 12 weeks after initiating a new OA and determine factors associated with these changes. Manuscript one introduces a conceptual model derived from the Extended Common-Sense Model of Self-Regulation to explain the phenomenon of medication beliefs using a theory derivation approach.Manuscript two examines: 1) whether positive and negative components of medication beliefs change over time; 2) summed symptom severity and interference indices on the positive and negative components of medication beliefs over time and; 3) the influence of depression and cognitive effectiveness on the positive and negative components of medication beliefs over time and over and above the summed symptom severity and interference indices. A total of 272 participants completed the baseline interview. The sample was predominantly Caucasian (91%), diagnosed with stage four cancer (71%), and had a mean age of 61.39 (SD = 2.22) years. The most prevalent cancers were gastrointestinal (32%) and breast cancer (21%). Kinase inhibitors (47%) and cytotoxics (35%) were the most frequent forms of OA treatment. Linear mixed models (LME) revealed Necessity beliefs increased over time, mean difference 0.112, SE=0.055, p = .04. Concern beliefs only changed when symptom severity and interference were introduced into the LME. A decrease in Necessity beliefs was significantly associated with higher levels of depressive symptoms (B = -0.012, SE = 0.004, p = <.01). Increased Concern beliefs were significantly associated with patient-reported symptom severity (B = 0.009, SE = 0.001, p = <.01), symptom interference (B = 0.010, SE = 0.001, p = <.01), depressive symptoms (B = 0.021, SE = 0.003, p = <.01), cognitive effectiveness (B = -0.006, SE = 0.001, p = <.01) and chronic conditions requiring medications (B = 0.048, SE = 0.014, p = <.01). Manuscript three aimed to: 1) explore the relationship of documented adverse events on positive and negative components of medication beliefs 12 weeks after initiating a new OA and 2) determine whether patients who experience a permanent physician-directed OA stoppage differ in their medication beliefs compared to those with no permanent physician-directed OA stoppage. A total of 164 participants were included in the study. Mean age was 62.60 (SD = 10.46) years. The sample was predominantly Caucasian (88%). Breast (26%) and gastrointestinal cancers (23%) were the most prevalent types of cancer and 72% had stage four cancer. A regression analysis showed patients experiencing zero (B = 0.50, SE = 0.21, p = .02), one (B = 0.70, SE = 0.21, p = <.01), or two (B = 0.82, SE = 0.23, p = <.01) adverse events had significantly higher Necessity beliefs compared to those with three or more adverse events. Independent t-tests followed by a regression analysis revealed patients not experiencing a physician-directed OA stoppage had significantly higher Necessity beliefs (B = 0.80, SE = 0.23, p = <.01) compared to those who had experienced a permanent physician-directed OA stoppage. Results support that the two components of medication beliefs are influenced by different factors. Nurses should elicit medication beliefs at each clinic visit, especially when patients experience increasing levels of symptom severity/interference or adverse events, depressive symptoms, compromised cognitive effectiveness, and when patients experience a permanent physician-directed OA stoppage. Screening medication beliefs can also serve to address ethical issues regarding how long patients remain on OAs that cause more harm than benefit at the end of life. Future research on medication beliefs is needed with more diverse ethnic backgrounds.
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