Environment and Breast Cancer: Science Review

Evidence From Humans
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Epidemiologic and molecular risk factors for contralateral breast cancer among young women
Li, C. I., Malone, K. E., Porter, P. L., Daling, J. R. British Journal of Cancer. 2003. 89:3, 513-8.
Topic area
Body size
Study design
Prospective cohort
Study Participants
Number of Cases
77 women diagnosed for second primary contralateral breast cancer (CBC)
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Number in Cohort
Cohort: 1,285 (invasive only)
Cohort participation rate
Retention/participation exceeded 70% for exposed a
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: women interviewed and participated in one of two population based case-control studies based in western Washington state; diagnosed with invasive breast cancer from 1/83-4/90 or from 5/90-12/92 at age 45 or younger; resided in King, Pierce or Snohomish counties Ex: women diagnosed with in situ breast cancer; women born before 1945
Comment about participation selection
Strengths: good participation rate (83.9%); interviews performed by trained interviewers; analyzed CBC by tumor stage, histology and size; tumor tissue sufficient for assays were available for 907 (70.6%) of the study participants; One of the first studies to analyze BMI and CBC risk among women diagnosed with their first breast cancer before the age of 45 Limitations: Anthropometric data were self-reported; small number of CBC cases
Exposure Investigated
Exposures investigated
BMI and weight
How exposure was measured
Questionnaire, in person
Exposure assessment comment
Anthropometric data were self-reported
Breast cancer outcome investigated
Breast cancer recurrence or progression (CBC)
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
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, year at diagnosis, stage, chemotherapy, study in which the patient was a participant
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Strength of associations reported
Obese women BMI > 30 diagnosed with their first breast cancer had an increased risk of contralateral breast cancer (CBC) compared to women with a BMI < 19.9, HR=2.6(1.1-5.9)
Heavy women, weight >156 lbs vs <123lbs, diagnosed with their first breast cancer had an increased risk of CBC, HR=2.2(1.1-4.4)
Results Comments
Follow-up: through 12/2001
Author address
Fred Hutchinson Cancer Research Center, Division of Public Health Sciences, 1100 Fairview Avenue North, MP-381, PO Box 19024, Seattle, WA 98109-1024, USA. cili@fhcrc.org