Medline ® Abstracts for References 9,12,13
of 'Clinical features, diagnosis, and staging of newly diagnosed breast cancer'
Breast cancer incidence, 1980-2006: combined roles of menopausal hormone therapy, screening mammography, and estrogen receptor status.
Glass AG, Lacey JV Jr, Carreon JD, Hoover RN
J Natl Cancer Inst. 2007;99(15):1152. Epub 2007 Jul 24.
BACKGROUND: Breast cancer incidence has been rising since at least 1935-1939, but recent US data reveal a statistically significant decline in breast cancer incidence in 2003 that persisted through 2004. Identifying the specific contributions of the potential causes of this long-term increase and the recent decrease in incidence has been challenging. Marked changes in rates of mammography screening and use of menopausal hormone therapy since 1980 have added further complexity. We examined the potential association between menopausal hormone therapy use and recent changes in breast cancer incidence.
METHODS: Using tumor registry, clinical, pathology, and pharmacy data from Kaiser Permanente Northwest, a large prepaid US health plan, we compared age-specific and age-adjusted breast cancer incidence rates (2-year moving averages) with use of screening mammography and dispensed menopausal hormone therapy prescriptions between 1980 and 2006. Temporal changes in incidence rates were assessed via joinpoint regression.
RESULTS: A total of 7386 incident invasive breast cancers were diagnosed in plan members from 1980 through 2006. Overall age-adjusted breast cancer incidence rates per 100,000 women rose 25% from the early 1980s (105.6) to 1992-1993 (131.7) and an additional 15% through 2000-2001 (151.3), then dropped by 18% to 2003-2004 (123.6) and edged up slightly in 2005-2006 (126.2). These patterns were largely restricted to women aged 45 years or older and to estrogen receptor-positive (ER+) breast cancers. Incidence rates of ER-negative tumors experienced neither of the rises seen for ER+ tumors but also fell precipitously from 2003 through 2006. Rates of mammography screening sharply increased from 1980 to 1993 but then leveled off, and 75%-79% of women aged 45 years or older received a mammogram at least once every 2 years from 1993 through 2006. Menopausal hormone therapy dispensings, particularly of estrogen-plus-progestin formulations, increased from 1988 to 2002 but then dropped by approximately 75% after 2002.
CONCLUSIONS: From 1980 through 2006, quantitative and qualitative trends in breast cancer incidence rates, particularly for ER+ tumors, parallel major changes in patterns of mammography screening and use of menopausal hormone therapy.
Oncology Research, Center for Health Research, Kaiser Permanente Northwest, 3800 N Interstate Ave, Portland, OR 97227, USA. email@example.com
Breast cancer after use of estrogen plus progestin in postmenopausal women.
Chlebowski RT, Kuller LH, Prentice RL, Stefanick ML, Manson JE, Gass M, Aragaki AK, Ockene JK, Lane DS, Sarto GE, Rajkovic A, Schenken R, Hendrix SL, Ravdin PM, Rohan TE, Yasmeen S, Anderson G, WHI Investigators
N Engl J Med. 2009;360(6):573.
BACKGROUND: Following the release of the 2002 report of the Women's Health Initiative (WHI) trial of estrogen plus progestin, the use of menopausal hormone therapy in the United States decreased substantially. Subsequently, the incidence of breast cancer also dropped, suggesting a cause-and-effect relation between hormone treatment and breast cancer. However, the cause of this decrease remains controversial.
METHODS: We analyzed the results of the WHI randomized clinical trial--in which one study group received 0.625 mg of conjugated equine estrogens plus 2.5 mg of medroxyprogesterone acetate daily and another group received placebo--and examined temporal trends in breast-cancer diagnoses in the WHI observational-study cohort. Risk factors for breast cancer, frequency of mammography, and time-specific incidence of breast cancer were assessed in relation to combined hormone use.
RESULTS: In the clinical trial, there were fewer breast-cancer diagnoses in the group receiving estrogen plus progestin than in the placebo group in the initial 2 years of the study, but the number of diagnoses increased over the course of the 5.6-year intervention period. The elevated risk decreased rapidly after both groups stopped taking the study pills, despite a similar frequency of mammography. In the observational study, the incidence of breast cancer was initially about two times as high in the group receiving menopausal hormones as in the placebo group, but this difference in incidence decreased rapidly in about 2 years, coinciding with year-to-year reductions in combined hormone use. During this period, differences in the frequency of mammography between the two groups were unchanged.
CONCLUSIONS: The increased risk of breast cancer associated with the use of estrogen plus progestin declined markedly soon after discontinuation of combined hormone therapy and was unrelated to changes in frequency of mammography.
Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA. firstname.lastname@example.org
Recent breast cancer incidence trends according to hormone therapy use: the California Teachers Study cohort.
Marshall SF, Clarke CA, Deapen D, Henderson K, Largent J, Neuhausen SL, Reynolds P, Ursin G, Horn-Ross PL, Stram DO, Templeman C, Bernstein L
Breast Cancer Res. 2010;12(1):R4. Epub 2010 Jan 8.
INTRODUCTION: Recent, international declines in breast cancer incidence are unprecedented, and the causes remain controversial. Few data sources can address breast cancer incidence trends according to pertinent characteristics like hormone therapy use history.
METHODS: We used the prospective California Teachers Study to evaluate changes in self-reported use of menopausal hormone therapy (HT) between 1995 to 1996 and 2005 to 2006 and age-adjusted breast cancer incidence among 74,647 participants aged 50 years or older. Breast cancer occurrence was determined by linkage with the California Cancer Registry.
RESULTS: During 517,286 woman years of follow up, 565 in situ and 2,668 invasive breast cancers were diagnosed. In situ breast cancer incidence rates in this population did not change significantly from 2000 to 2002 to 2003 to 2005, whereas rates of invasive breast cancer declined significantly by 26.0% from 528.0 (95% confidence intervals (CI) = 491.1, 564.9) per 100,000 women in 2000 to 2002 to 390.6 (95% CI = 355.6, 425.7) in 2003 to 2005. The decline in invasive breast cancer incidence rates was restricted to estrogen receptor-positive tumors. In 1996 to 1999 and 2000 to 2002 invasive breast cancer incidence was higher for women who reported current HT use especially estrogen-progestin (EP) use at baseline than for never or past users; but by 2003 to 2005 rates were comparable between these groups. For women who were taking EP in 2001 to 2002,75% of whom had stopped use by 2005 to 2006, incidence had declined 30.6% by 2003 to 2005 (P = 0.001); whereas incidence did not change significantly for those who never took HT (P = 0.33).
CONCLUSIONS: Few data resources can examine prospectively individual HT use and breast cancer diagnosis. Stable in situ breast cancer rates imply consistent levels of screening and suggest recent declines in invasive breast cancer to be explained predominantly by changes in HT use.
Department of Epidemiology, School of Medicine, University of California, Irvine, 224 Irvine Hall, Irvine, CA 92697, USA. email@example.com