title: Protein S and protein C level changes with adjuvant tamoxifen therapy in postmenopausal women.
abstract: 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.
authors.affiliation: Cancer Prevention Program, University of Wisconsin Comprehensive Cancer Center, Madison.
authors.forename: C C
authors.initials: CC
authors.lastname: Mamby
authors.forename: R R
authors.initials: RR
authors.lastname: Love
authors.forename: J M
authors.initials: JM
authors.lastname: Feyzi
mesh_terms: D001943:Breast Neoplasms / Q000097:blood* / Q000188:drug therapy*; D017024:Chemotherapy, Adjuvant; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008875:Middle Aged; D010919:Placebos; D017698:Postmenopause; D011486:Protein C / Q000032:analysis*; D017293:Protein S / Q000032:analysis*; D013629:Tamoxifen / Q000627:therapeutic use* / Q000633:toxicity; D013924:Thrombophlebitis / Q000139:chemically induced
chemical_list: D010919:Placebos; D011486:Protein C; D017293:Protein S; D013629:Tamoxifen