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While a personal history of endometrial cancer—cancer of the uterine
lining—has been linked to a higher risk of breast cancer, a new study finds that a family
history of breast cancer does not increase the chances that women will develop
endometrial cancer. The study, which followed nearly 38,000 women over a 14-year period,
should help ease concerns about endometrial cancer among women whose families have been
affected by breast cancer.
Endometrial cancer is a disease affecting the lining of the uterus. The American Cancer
Society estimates that approximately 39,300 women will be diagnosed with uterine cancer in
2002, and 95% of these diagnoses will be endometrial cancer. Approximately 6, 600
Americans will die from uterine cancer this year. Eighty-four percent of women diagnosed
with endometrial cancer live five or more years after their diagnosis.
To examine the relationship between endometrial cancer and a family history of breast
cancer, Neely Kazerouni of the National Cancer Institute and colleagues followed 37,583
women from 1979 to 1998. The researchers collected information on the breast cancer
history of the women’s mothers, sisters, daughters, aunts, and grandmothers. A total
of 648 women were diagnosed with endometrial cancer during the follow-up.
After taking into consideration established risk factors for endometrial cancer (see
bulleted list below), the researchers determined that a family history of breast cancer
did not increase the risk of endometrial cancer in the study. However, they did find a
personal history of breast cancer increased endometrial risk by 30%.
The results confirm two previous studies which also failed to find an association
between endometrial cancer and a family history of breast cancer. A study published in
1972 did find a link between endometrial cancer risk and a family history of breast
cancer, but Kazerouni’s team commented that the study included women with two or more
relatives with breast cancer; thus, the families may have had a higher than average
predisposition to cancer.
The current study did find a non-significant increased risk of endometrial cancer among
women with a first-degree family member (mother and/or sisters) with bilateral breast
cancer (cancer in both breasts). However, because other factors typically associated with
inherited cancer (such as an early age at diagnosis) were not seen in these cases, the
researchers are not inclined to believe that genetics played a key role in these cases.
Thus, a family history of breast cancer does not seem to be an important endometrial
cancer risk factor; although a personal history of breast cancer does increase the
risk of developing endometrial cancer. The researchers suggest that environmental,
hormonal and/or genetic risk factors may be responsible for this link.
Risk factors for endometrial cancer include:
- Advancing age
- Family history
- Early onset of menstruation (before
age 12) or late menopause (after age 50)
- Never having children
- Use of the breast cancer drug tamoxifen
- Estrogen therapy among women with intact uteruses
(progesterone counteracts risk)
Risk factors for breast cancer include:
- Advancing age
- Family history
- Genetic predisposition (such as mutations of BRCA1 or BRCA2 gene)
- Early onset of menstruation (before age 12) or late menopause (after age 50)
- Never having children or having a first child after age 30
- Long term hormone replacement therapy (more than five years)
Additional Resources and References
- The report, "Family history of breast cancer as a determinant of the risk of
developing endometrial cancer: a nationwide cohort study," is published in the
November 2002 issue of the Journal of Medical Genetics, http://jmg.bmjjournals.com/
- To learn more about endometrial cancer, please visit the American Cancer Society website
at http://www.cancer.org/
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