Environment and Breast Cancer: Science Review
About
Menopausal estrogen and estrogen-progestin replacement therapy and breast cancer risk. [see comment] [erratum appears in JAMA 2000 Nov 22-29;284(20):2597]
Schairer, C., Lubin, J., Troisi, R., Sturgeon, S., Brinton, L., Hoover, R. JAMA. 2000. 283:4, 485-91.
Topic area
Body size
Body size
Study design
Prospective cohort
Prospective cohort
Funding agency
Other: Robert Wood Johnson Foundation's Changes in
Other: Robert Wood Johnson Foundation's Changes in
Study Participants
Number of Cases
2,082 (1,456 invasive) (255 in situ) (369 without pathology reports) (2 uncertain)
2,082 (1,456 invasive) (255 in situ) (369 without pathology reports) (2 uncertain)
Menopausal Status
The menopausal status of women included in this study is listed here.
Post menopausal
Number in Cohort
Cohort: 46,355
Cohort: 46,355
Cohort participation rate
Retention/participation exceeded 70% for exposed a
Retention/participation exceeded 70% for exposed a
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: participated in the Breast Cancer Detection Demonstration Project (BCDDP); underwent breast surgery during screening period; had recommendations by the project for a surgical consultation but did not have either a biopsy of aspiration performed; had neither surgery nor recommendation for surgical consultation during screening participation; women who were menopausal before the start of the follow-up period or who became menopausal during the course of the study; women who stopped menstruating because of a hysterectomy but who retained at least 1 ovary
Ex: women who reported prophylactic bilateral mastectomies; previous diagnosis of breast cancer before the start of follow-up; women who used menopausal hormones in the form of shots, patches or creams
Comment about participation selection
Strengths: large cohort study with 473,687 person years of follow-up, 46,355 participants and 2,082 cases; tumors were classified by histology and nodal status; analyzed breast cancer risk association with duration of Estrogen-only use and Estrogen-Progestin only use by BMI; follow-up status was carried out in 3 phases Limitations: anthropometric data self-reported; several episodes of hormone use that occurred before breast cancer diagnosis were reported after diagnosis which raises the possibility of differential recall by cases and noncases;
Strengths: large cohort study with 473,687 person years of follow-up, 46,355 participants and 2,082 cases; tumors were classified by histology and nodal status; analyzed breast cancer risk association with duration of Estrogen-only use and Estrogen-Progestin only use by BMI; follow-up status was carried out in 3 phases Limitations: anthropometric data self-reported; several episodes of hormone use that occurred before breast cancer diagnosis were reported after diagnosis which raises the possibility of differential recall by cases and noncases;
Exposure Investigated
How exposure was measured
Questionnaire, self-administered Questionnaire, by telephone
Questionnaire, self-administered Questionnaire, by telephone
Exposure assessment comment
Anthropometric data self-reported
Anthropometric data self-reported
Statistical Analysis
Breast cancer outcome investigated
Primary breast cancer
Primary breast cancer
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
No
Confounders considered
Other breast cancer risk factors, such as family history, age at first birth, and hormone replacement therapy use, that were taken into account in the study.
Adequately controlled, Confounders: age, age at menopause, education, mammographic screening and BMI
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
No
Description of major analysis
DCIS/LCIS Effect modifiers: duration of estrogen use and duration of estrogen-progestin use Follow-up: 10.2 years (mean)
DCIS/LCIS Effect modifiers: duration of estrogen use and duration of estrogen-progestin use Follow-up: 10.2 years (mean)
Strength of associations reported
Association between postmenopausal breast cancer risk and estrogen only HRT use for a duration of >16 years in women with a BMI <24.4, RR=1.6(1.2-2.2) trend p=0.001
Association between postmenopausal breast cancer risk and estrogen only HRT use for a duration of >16 years in women with a BMI >24.4, RR=0.8(0.6-1.3) trend p=0.46
Association between breast cancer risk and estrogen-progestin only HRT use for a duration of > 4 years in women with a BMI <24.4, RR=2.0(1.3-3.0) trend p=0.01
Association between breast cancer risk and estrogen-progestin only HRT use for a duration of > 4 years in women with a BMI >24.4, RR=1.3(0.7-2.4) trend p=0.28
Association between postmenopausal breast cancer risk and estrogen only HRT use for a duration of >16 years in women with a BMI <24.4, RR=1.6(1.2-2.2) trend p=0.001
Association between postmenopausal breast cancer risk and estrogen only HRT use for a duration of >16 years in women with a BMI >24.4, RR=0.8(0.6-1.3) trend p=0.46
Association between breast cancer risk and estrogen-progestin only HRT use for a duration of > 4 years in women with a BMI <24.4, RR=2.0(1.3-3.0) trend p=0.01
Association between breast cancer risk and estrogen-progestin only HRT use for a duration of > 4 years in women with a BMI >24.4, RR=1.3(0.7-2.4) trend p=0.28
Results Comments
Risk in heavier women did not increase with the use of estrogen only or estrogen-progestin only hormones.
Risk in heavier women did not increase with the use of estrogen only or estrogen-progestin only hormones.
Author address
National Cancer Institute, Division of Cancer Epidemiology and Genetics, Rockville, MD 20852-7234, USA. schairec@exchange.nih.gov
National Cancer Institute, Division of Cancer Epidemiology and Genetics, Rockville, MD 20852-7234, USA. schairec@exchange.nih.gov