The contribution of patient factors to nonadherence with self-administered cancer chemotherapy along with its prevalence was studied. Fifty-one patients with breast cancer enrolled in protocols that included the orally administered medications Cytoxan (cyclophosphamide) and/or prednisone were interviewed and assessed at five points in time over a 6-month period. Two summary measures of patient nonadherence derived by self-report were developed: (1) dosage, the overall percentage of drug missed during 26 weeks of treatment; and (2) behavioral, the percentage of behavioral events or prescribing occasions on which a criterion level of drug was missed. Twenty-two patients (43%) met criteria for noncompliance according to both behavioral and dosage definitions. Univariate analyses showed more nonadherence in the clinic and private community settings than in the academic setting. Stepwise multiple logistic regression analyses assessed the contribution of patient demographic, psychologic, and physical symptom factors on patient noncompliance. In the regression analyses patient noncompliance was associated with (1) treatment location, more nonadherence in the private community-based treatment sector than in the academic setting; and
(2) income, more nonadherence among those having lower incomes. In assessing total dose requirements in clinical research trials, rates of patient nonadherence need to be considered, and treatment location controlled.
Cancer 65:17-22, 1990.
ATIENT noncompliance with treatment protocols is P a major medical issue that is receiving increasing attention. Direct effects of compliance on health outcome have been observed with treatment effectiveness itself at stake.' Bonadonna and Valagussa2 demonstrated that successful adherence to intravenous chemotherapy protocols for the treatment of breast carcinoma is associated with dramatically improved outcome. They refer to noncompliance with patient administered oral cyclophosphamide as a factor in assessing clinical trials effectiveness in breast cancer protocols. In addition to hampering successful therapy, patient noncompliance has been associated with higher hospitalization rates, longer lengths of