Abstract P4-13-04: Estrogen and Avoidance of Invasive Breast Cancer, Coronary Heart Disease and All-cause Mortality. Public Health Impact of Estrogen Guidelines for Women entering Menopause

BACKGROUND. Estrogen [E] for women entering menopause is not perceived beneficial for either iBrCa or CHD. However, data from RCTs suggest that use of Estrogen reduces: a. rates of invasive breast cancer [iBrCa], andb. atherogenesis, vessel pathology and in certain age groups, coronary heart disease [CHD].

OBJECTIVES: To estimate the population-level impact of Estrogen as part of hormone replacement therapy [HRT] for women entering menopause on rates of iBrCa, CHD and all cause mortality [AC- Mort] that could result from a change of Practice where Estrogen would be recommended for women entering menopause.

METHODOLOGY. Annualized rates of iBrCa, CHD and AC-Mort in women age 50–59, and annualized iBrCa rates for all participants and those without Past History of Benign Breast Disease [PHBBD] extracted from the results of the Women's Health Initiative trial [E] alone vs placebo [Refs 1,2], were applied to estimate the reduction in the Number of Avoided Events per 100,000 female population per annum [NAE].

The [NAE] over 10 years follow up was calculated as: NAE = (P − E) × 100,000 × 10 where P was the annualized rate among placebo participants and E was the annualized rate among Estrogen participants.

RESULTS. [Table 1]. Taking 100,000 exposed versus unexposed women age 50–59, and rate reduction due to [E] of −41% [HR=0.59], −20% [HR=0.80] and −27% [HR=0.73] for CHD, iBrCa and AC-Mort [Ref 1,2], respectively, there will be annual avoidance of −130 cases of CHD, −60 of iBrCa, and −130 of deaths from any cause. iBrCa annual avoidance for women any age, and those without PHBBD, were −80 and −150 events, respectively.

Protective Effect of Estrogen (E2) and Increased Risk of E2 Plus Progestin (Prog) on Breast Cancer (BrCa). The 2009 Review of the Women's Health Initiative (WHI) Hormone Replacement Therapy (HRT) Published Trials

INTRODUCTION & METHODOLOGY.The objective of this review is to identify from the two WHI published randomized HRT trials the BrCa risk or benefit, with a special focus on different impact of E2-alone vs E2+Prog on human breast carcinogenesis (BrCa-genesis).In the 1st trial (JAMA 2002, 2007), healthy women age 50 - 79 were randomized to E2 plus Prog versus placebo (Plac). Reviewed were Hazard ratios (HRs) for all pts and also for those with or without prior Hormone use. Mean follow up was 5.2 years.In the 2nd trial (JAMA 2004, 2006), women with hysterectomy age 50 - 79 were randomized to E2 alone (without Prog) versus Plac. Mean follow up was 7.1 years. Reviewed were all pts, and also subsets with or without prior E2 or Prog; with or without prior history of Benign Breast Disease (PHBrD); and with or without prior history of a 1st degree relative with BrCa (PH1stRelBrCa).RESULTS.Invasive BrCa incidence:N (%)HR95% C.I.1st TrialAll participants:16,608 (100%)1.260.83 - 1.97No prior Hormone use:12,304 (74.1%)1.060.81 - 1.38Prior Hormone use <5 yrs:3,005 (18.1%)2.131.15 - 3.94*Prior Hormone use 5 - 10 yrs:783 (4.7%)4.611.01 - 21.02*2nd TrialAll participants:10,739 (100%)0.800.62 - 1.04No prior hormone use:5,763 (53.7%)0.650.46 - 0.92*Prior E2 use:4,976 (46.3%)0.980.67 - 1.44Prior E2 + PROG use:468 (4.4%)2.350.60 - 9.14No PHBrD:7,681 (71.5%)0.570.41 - 0.78*No PH1stRelBrCa8,554 (80.0%)0.680.50 - 0.92*CONCLUSION:1. Results from the 1st trial show that concomitant use of E2 with Prog, particularly in women with prior Hormone use, is associated with increased BrCa hazards.2. The results of the 2nd HRT trial indicate that use of HRT with E2 alone is associated with a reduction in BrCa incidence, significant in the majority of women with no prior BrCa risk factors. Also the results show that prior Prog but not prior E2 elevate the risk.3. These data indicate that HRT with E2 alone has a BrCa protective effect, while adding Prog increases the risk.4. These results are also compatible with a dual E2 effect on BrCa-genesis, where exogenous E2 are protective, but endogenous E2 [endE2] are carcinogenic, as shown from decades of anti-end E2 research with Tamoxifen, oophorectomy or Aromatase inhibitors.5. Based on these data we propose that in women with hysterectomy and no prior history of risk factors, the use of HRT with E2 alone as chemoprevention is plausible, and needs urgent verification.* significance, "p" <0.05.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 908.

Breast cancer mortality reduction in the western world: therapeutic versus diagnostic interventions. Implications for cancer care organization processes

Abstract #6083

INTRODUCTION. Recent epidemiology data show a substantial Breast Cancer (BrCa) mortality reduction in the western countries over the last decade. The literature indicates that both Adjuvant systemic treatments (Adj. SystTh) and Screening mammography (ScrM) contribute, but their interaction is not clear.
 Our study examines if contribution of Adj. SystTh separate from ScrM could be more clearly identified; and also, - as a second objective, - if organization of cancer care could be correlated with BrCa mortality outcomes.
 METHODOLOGY:
 The mortality trends were compared among three Provinces of Canada with different Levels of Provincial Diagnostic and Therapy Guidelines (PDTG):
 LEVEL I: most uniform coordination of PDTG: British Columbia (Brit.Col.), with a single Provincial budget; earliest implementation of Provincial Community Oncology Program (since the mid-1970's); and a uniform start of Adj. SystTh (late 1970's); and of ScrM (late -1980's).
 LEVEL II: medium (Ontario).
 LEVEL III: least uniform (Atlantic Provinces)*.
 BrCa annual age-standardized mortality rates per 100,000/population were obtained from Statistics Canada for the years 1950-2004, and expressed relative to the year 1950 (the baseline).
 RESUTLS: The 1950 BrCa mortality rates were: 30.9 for Canada; 31.4 for BC; 30.7 Ontario; 26.1 for Atlantic Provinces*.
 
 CONCLUSIONS:
 While both Adj. SystTh and ScrM contribute towards recent BrCa mortality reduction, the British Columbia data indicate that the impact of Adj. SystTh antedates that of ScrM, at least by a decade.
 Our data support a correlation of BrCa mortality trends with the organization of cancer care: Effective implementation of PDTG (- i.e. incorporating early curative interventions into guidelines), will have a strong impact on mortality trends, particularly if executed
 a. ongoingly,
 b. uniformly, and
 c. across the whole population.
 Our data therefore indicate that early implementation of curative systemic therapy - or of any curative intervention - is essential, as their delay may prevent materialization of survival gains.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6083.