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Early discontinuation of tamoxifen
A Lesson for oncologists
Version of Record online: 22 JAN 2007
Copyright © 2007 American Cancer Society
Volume 109, Issue 5, pages 832–839, 1 March 2007
How to Cite
Barron, T. I., Connolly, R., Bennett, K., Feely, J. and Kennedy, M. J. (2007), Early discontinuation of tamoxifen. Cancer, 109: 832–839. doi: 10.1002/cncr.22485
- Issue online: 22 FEB 2007
- Version of Record online: 22 JAN 2007
- Manuscript Accepted: 28 NOV 2006
- Manuscript Revised: 23 NOV 2006
- Manuscript Received: 27 SEP 2006
- breast cancer;
Five years of treatment provides the optimum duration of tamoxifen therapy for the prevention of breast cancer recurrence and mortality. Durations of adjuvant tamoxifen therapy less than 5 years are associated with poorer outcomes for breast cancer patients. The purpose of the study was to assess rates of tamoxifen nonpersistence (early discontinuation) in women aged 35 years or older using prescription refill data from a national prescribing database.
A cohort of 2816 women commencing tamoxifen as initial hormonal therapy was identified between January 2001 and January 2004. The cumulative tamoxifen persistence rate was calculated for these women and the relation between nonpersistence and clinical and demographic variables assessed.
Within 1 year of commencing treatment the cumulative tamoxifen nonpersistence rate was 22.1%. This is twice the rate of treatment discontinuation observed in other studies by this time. By the end of follow-up at 3.5 years, the cumulative nonpersistence rate had increased to 35.2%. Determinants of nonpersistence identified included age and a history of antidepressant use.
The rate of nonpersistence with tamoxifen therapy is higher than previously reported. This study demonstrates that persistence with tamoxifen cannot be assumed and raises concerns about persistence with other oral hormonal therapies for breast cancer and oral antineoplastics in general. Oncologists need to identify those at risk of nonpersistence and develop strategies to combat this barrier to treatment success. Cancer 2007. © 2007 American Cancer Society.