Applying the theory of planned behavior to examine adjuvant endocrine therapy adherence intentions

• Published in: Psycho-oncology (Chichester, England) Vol. 28; no. 1; pp. 187 - 194
• Main Authors: Hurtado‐de‐Mendoza, Alejandra, Carrera, Pilar, Parrott, W. Gerrod, Gómez‐Trillos, Sara, Perera, Robert A., Sheppard, Vanessa B.
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.01.2019
• Subjects: Adherence; adjuvant endocrine therapy; Adjuvants; Adult; Ambivalence; Antineoplastic Agents, Hormonal - therapeutic use; Breast cancer; Breast Neoplasms - drug therapy; Breast Neoplasms - psychology; Cancer Survivors - psychology; Chemotherapy, Adjuvant; Combined Modality Therapy; Drugs; Emotions; Endocrine therapy; Expectations; Female; Health behavior; Humans; Medication Adherence - psychology; Middle Aged; Patient compliance; Positive emotions; Psychological Theory; Self Report; Survivor; Theory of planned behavior; Women; theory of planned behavior; adjuvant endocrine therapy; breast cancer; emotions; adherence
• ISSN: 1057-9249; 1099-1611
• DOI: 10.1002/pon.4931

Objective Adherence to adjuvant endocrine therapy (AET) in breast cancer survivors is suboptimal. Using the theory of planned behavior (TPB), this study aimed to identify the strongest predictors from the TPB of AET intentions and past behavior and assessed whether ambivalence and anticipatory emotions increased the predictive capacity of TPB. Methods Two hundred eighty women diagnosed with hormone positive (HR+) breast cancer who filled at least one prescription of AET responded to a survey measuring TPB constructs, attitudinal ambivalence, and anticipatory emotions. The outcomes were intentions to adhere to AET and past medication adherence (previous 2 weeks). Results The TPB explained 66% of intentions to adhere to AET (P < 0.001). Ambivalence did not improve the TPB model's predictive value. When emotions were included with TPB, the model explained 70% of adherence intentions F11,226 = 52.84, P < 0.001 (R2c = .70). This increase of 4% in predictability was statistically significant (ΔR2 = 0.04), F6, 226 = 7.90, P < 0.001. Women who self‐reported nonadherence in the past 2 weeks differed significantly in the TPB variables, ambivalence, and anticipatory emotions from adherent women. Nonadherent participants reported lower‐future intentions to adhere F1, 236 = 5.63, P = 0.018. Conclusions Results suggest key concepts, such as anticipatory positive emotions that should be addressed in future interventions to enhance AET adherence and survivorship.