Presenter: A. H. Partridge, P. S. Wang, E. P. Winer, J. L. Avorn Affiliation: Dana-Farber Cancer Institute, Boston, MA; Brigham and Women's Hospital, Boston, MA
Tamoxifen has been shown to help prevent breast cancer recurrence and death in women with early breast cancer. Yet, non-compliance for a number of reasons appears to be an issue. This study from the Dana?Farber Institute attempts to quantify the level of non-adherence with tamoxifen in a sample of women who have just started adjuvant therapy with this hormonal therapy.
Materials and Methods:
This study included all filled prescriptions among continuously enrolled patients in New Jersey's Medicaid and Pharmaceutical Assistance to the Aged and Disabled programs who filled a first prescription for tamoxifen from 1990-1996 (N = 2356).
The number of "days covered" by filled tamoxifen prescriptions in the 365-day period following initiation of therapy was calculated, and patients' demographic and clinical characteristics were assessed.
The outcome measures were:
The proportion of days during the study year for which patients had filled prescriptions for tamoxifen
predictors of good vs. poor adherence.
Patients filled prescriptions for tamoxifen for a mean of 77% of days in the study year.
30% of patients had fewer than 80% of days with drug available during the year.
Multivariable analysis indicated that patients at the extremes of age (=45 and =85 years), and nonwhite patients had significantly lower rates of adherence, after adjusting for possible confounders.
After excluding patients with an identifiable reason for possible therapeutic discontinuation of tamoxifen during the study year, predictors and overall adherence did not change substantially.
46% of patients on tamoxifen did not see an oncologist.
The mean level of adherence to tamoxifen during the first year of therapy is higher than rates seen with other chronic oral medications, but nearly a third of patients may be at risk for inadequate clinical response because of poor adherence.
Such poor adherence cannot be predicted using demographic or clinical data, with the exception of age and race.
Further efforts are necessary to document and prevent suboptimal adherence, particularly in younger, older, and non-white populations.
It is important to note that it is difficult to tease out recurrence rates and toxicity data from population studies. Thus, some of the non-adherence seen in this study may be due to oncologist discontinuing tamoxifen and not patient non-compliance. While cancer patients adhere to chronic use of oral medications better than their non-cancer counter parts, there is room for improvement.
Apr 19, 2010 - Despite a strong biologic rationale, there may be no association between concomitant usage of cytochrome P450 2D6 inhibitors such as selective serotonin reuptake inhibitors and breast cancer recurrence in patients with early-stage disease who are treated with adjuvant tamoxifen, though there is an association between poor tamoxifen adherence and increased risk of breast cancer events, according to a study published online April 12 in the Journal of Clinical Oncology.