In the National Surgical Adjuvant Breast and Bowel Project P-l Breast Cance
r Prevention Trial (BCPT), women considered to be at high risk for developi
ng breast cancer who received tamoxifen experienced 49% and 50% reductions
in the risk of developing invasive and noninvasive breast cancer, respectiv
ely, compared with women receiving placebo. Although the BCPT addressed the
clinical benefits of tamoxifen, this study sought to assess its cost effec
tiveness in the prevention of breast cancer in women at increased risk for
developing the disease. Women were considered to be at an increased risk if
they were: 1) 60 years of age or older, 2) age 35 to 59 years with a histo
ry of lobular carcinoma in situ, or 3) age 35 to 59 years with additional r
isk factors that made their 5-year predicted breast cancer risk at least as
great as that of women 60 years of age. A decision-analysis model was used
to estimate the incremental cost effectiveness of using tamoxifen compared
with no intervention as preventive therapy in age-group defined cohorts of
women who were at high risk for developing breast cancel: The analysis use
d data on the benefits and risks of tamoxifen as observed in the BCPT. In a
sub-group analysis, tamoxifen's cost effectiveness was also evaluated in w
omen who had had a hysterectomy, because of evidence that suggested an incr
eased risk of endometrial cancer in women receiving tamoxifen. Under conser
vative assumptions from a base-case analysis, the incremental cost effectiv
eness of tamoxifen is $41,372 per life-year gained for women age 35 to 49 y
ears, whereas for women age 50 to 59 years and 60 to 69 years, these values
are $68,349 and $74,981, respectively. For women with a previous hysterect
omy, tamoxifen's cost effectiveness is $46,060 per life-year gained. A stra
tegy of using tamoxifen in high-risk women to prevent breast cancer in high
-risk women may be cost effective, particularly in the 35-to-49 year-old ag
e group and in those of any age who have had a hysterectomy.