Tamoxifen citrate is a synthetic antiestrogen that provides survival benefit when given as adjuvant treatment in postmenopausal women with breast cancer. Venous thrombophlebitis may complicate tamoxifen treatment at a rate of approximately one per 800 treatment-years. To explore the possible procoagulant effects associated with tamoxifen therapy we evaluated changes in protein S and C activity levels in 58 postmenopausal women with surgically resected breast cancer who were disease-free and participating in a double-blind, placebo-controlled, randomized toxicity study of tamoxifen. The changes in protein C activities for the tamoxifen group (mean level = 113%) compared to those in the placebo group (mean level = 115%) were not significant (p = 0.45). Protein S activity levels increased while protein C activity levels decreased from baseline at 24 months in both tamoxifen and placebo groups. We conclude that the possible thrombophlebitis-promoting effect of tamoxifen in postmenopausal women is unlikely to be explained on the basis of protein S and protein C activity level changes.
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Early Breast Cancer Trialists' Collaborative Group: Systemic treatment of early breast cancer by hormonal, cytotoxic or immune therapy. Lancet 339(8784): 1–15, 1992
Fisher B, Redmond C, Dimmitrov NV: A randomized clinical trial evaluating tamoxifen in the treatment of patients with node-negative breast cancer who have estrogen receptor-positive tumors. New England Journal of Medicine 320: 479–484, 1989
Love RR, Surawicz TS, Williams EC: Antithrombin III level, fibrinogen level and platelet count changes with adjuvant tamoxifen therapy. Archives of Internal Medicine 152: 317–320, 1992
Love RR: The Wisconsin Tamoxifen Study: toxicity in nodenegative postmenopausal women. Cancer Investigation 6(5): 601–605, 1988
SAS/STAT User's Guide Version 6, Fourth Edition, Volume 2; Cary, NC: SAS Institute, Inc. 1989
Cochran WG, Cox GM: Experimental Designs. John Wiley & Sons, New York, 1950
Auger MJ, Mackie MJ: Effects of tamoxifen on blood coagulation. Cancer 61(7): 1316–1319, 1988
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Mamby, C.C., Love, R.R. & Feyzi, J.M. Protein S and protein C level changes with adjuvant tamoxifen therapy in postmenopausal women. Breast Cancer Res Tr 30, 311–314 (1994). https://doi.org/10.1007/BF00665973
- breast neoplasms
- protein S
- protein C