Cohort study examining tamoxifen adherence and its relationship to mortality in women with breast cancer

McCowan, C. , Shearer, J., Donnan, P.T., Dewar, J.A., Crilly, M., Thompson, A.M. and Fahey, T.P. (2008) Cohort study examining tamoxifen adherence and its relationship to mortality in women with breast cancer. British Journal of Cancer, 99(11), pp. 1763-1768. (doi: 10.1038/sj.bjc.6604758)

[img]
Preview
Text
73384.pdf - Published Version
Available under License Creative Commons Attribution Non-commercial Share Alike.

153kB

Abstract

Increasing duration of tamoxifen therapy improves survival in women with breast cancer but the impact of adherence to tamoxifen on mortality is unclear. This study investigated whether women prescribed tamoxifen after surgery for breast cancer adhered to their prescription and whether adherence influenced survival. A retrospective cohort study of all women with incident breast cancer in the Tayside region of Scotland between 1993 and 2002 was linked to encashed prescription records to calculate adherence to tamoxifen. Survival analysis was used to determine the effect of adherence on all-cause mortality. In all 2080 patients formed the study cohort with 1633 (79%) prescribed tamoxifen. The median duration of use was 2.42 years (IQR=1.04-4.89 years). Longer duration was associated with better survival but this varied over time. The hazard ratio for mortality in relation to duration at 2.4 years was 0.85, 95% CI=0.83-0.87. Median adherence to tamoxifen was 93% (interquartile range=84-100%). Adherence <80% was associated with poorer survival, hazard ratio 1.10, 95% CI=1.001-1.21. Persistence with tamoxifen was modest with only 49% continuing therapy for 5 years of those followed up for 5 years or more. Increased duration of tamoxifen reduces the risk of death, although one in two women do not complete the recommended 5-year course of treatment. A significant proportion of women have low adherence to tamoxifen and are at increased risk of death.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Mccowan, Professor Colin
Authors: McCowan, C., Shearer, J., Donnan, P.T., Dewar, J.A., Crilly, M., Thompson, A.M., and Fahey, T.P.
Subjects:R Medicine > RA Public aspects of medicine > RA0421 Public health. Hygiene. Preventive Medicine
R Medicine > RC Internal medicine > RC0254 Neoplasms. Tumors. Oncology (including Cancer)
R Medicine > RM Therapeutics. Pharmacology
College/School:College of Medical Veterinary and Life Sciences > Institute of Health and Wellbeing > Robertson Centre
Journal Name:British Journal of Cancer
Publisher:Nature Publishing Group
ISSN:0007-0920
ISSN (Online):1532-1827
Published Online:04 November 2008
Copyright Holders:Copyright © 2008 The Authors
First Published:First published inBritish Journal of Cancer 99(11):1763-1768
Publisher Policy:Reproduced under a Creative Commons License

University Staff: Request a correction | Enlighten Editors: Update this record