Adherence to tamoxifen over the five-year course
To estimate the proportion of older women who fail to complete 5 years of tamoxifen therapy and to identify predictors of non-adherence.
Patients and methods
We followed 462 women 65-years-old or older with stage I–IIIA breast cancer diagnosed in four US regions between 1996 and 1999 and who initiated tamoxifen therapy. We interviewed patients annually to assess tamoxifen adherence and collected information about predictors of adherence by medical record review, patient interview, and physician questionnaire.
Thirty-one percent of patients who started tamoxifen failed to complete the recommended 5-year course. Patients who had initial severe side effects [hazard ratio (HR) per side effect=1.2, 95% confidence interval (CI) 0.97, 1.5] or developed them (HR per new side effect=1.3, 95% CI 1.0, 1.6) were more likely to discontinue. Patients with more prescription medications at baseline were less likely to discontinue (HR per baseline prescription equaled 0.90, 95% CI 0.81, 0.99), whereas patients who added a prescription were more likely to discontinue (HR per new prescription equaled 1.2, 95% CI 1.0, 1.4). Patients with positive views of tamoxifen at baseline (HR for a 10-point higher score=0.93, 95% CI 0.83, 1.0) and an improving view over follow-up (HR for a 10-point positive change=0.93, 95% CI 0.87, 1.0) were less likely to discontinue.
Five years of tamoxifen confers a significant benefit beyond 1–2 years of tamoxifen, so physicians should ask patients about side effects, other prescriptions, and beliefs about tamoxifen and should educate them about the benefits of completing adjuvant therapy.
Keywordsadherence breast cancer tamoxifen
Data collection and analyses were supported by grants R01 CA/AG70818 from the National Cancer Institute and National Institute on Aging and R01 CA84506 from the National Cancer Institute. Dr Lash was supported, in part, by K07 CA87724 from the National Cancer Institute. Dr Silliman was supported, in part, by K05 CA92395 from the National Cancer Institute.
- 13.Fleming ID. AJCC Cancer Staging Manual 5th Edn. Lippincott Williams & Wilkins Philadelphia 1997Google Scholar
- 14.Ware J. SF-36 Health Survey, Manual and Interpretation Guide The Health Institute Boston 1993Google Scholar
- 17.Fisher B, Costantino J, Redmond C, Poisson R, Bowman D, Couture J, Dimitrov NV, Wolmark N, Wickerham DL, Fisher ER. A randomized clinical trial evaluating tamoxifen in the treatment of patients with node-negative breast cancer who have estrogen-receptor-positive tumors N Engl J Med 320: 479–484, 1989PubMedCrossRefGoogle Scholar
- 18.Fisher B, Costantino JP, Wickerham DL, Redmond CK, Kavanah M, Cronin WM, Vogel V, Robidoux A, Dimitrov N, Atkins J, Daly M, Wieand S, Tan-Chiu E, Ford L, Wolmark N. Tamoxifen for prevention of breast cancer: report of the National Surgical Adjuvant Breast and Bowel Project P-1 Study J Natl Cancer Inst 90: 1371–1388, 1998PubMedCrossRefGoogle Scholar
- 19.Winer EP, Hudis C, Burstein HJ, Wolff AC, Pritchard KI, Ingle JN, Chlebowski RT, Gelber R, Edge SB, Gralow J, Cobleigh MA, Mamounas EP, Goldstein LJ, Whelan TJ, Powles TJ, Bryant J, Perkins C, Perotti J, Braun S, Langer AS, Browman GP, Somerfield MR. American society of clinical oncology technology assessment on the use of aromatase inhibitors as adjuvant therapy for post-menopausal women with hormone-receptor-positive breast cancer: status report 2004 J Clin Oncol 23: 619–629, 2005PubMedCrossRefGoogle Scholar
- 21.Janis IL, Mann L. Psychological Analysis of Conflict, Choice, and Commitment Macmillan London 1977Google Scholar