http://www.medscape.com/viewarticle/528033?sssdmh=dm1.244580
<http://www.medscape.com/viewarticle/528033?sssdmh=dm1.244580&src=nldne>
&src=nldne
March 20, 2006 - Breast asymmetry is a risk factor for breast cancer,
according to the results of a study reported in the March 20 issue of
Breast Cancer Research.
"It has been shown in our previous work that breast asymmetry is related
to several of the known risk factors for breast cancer, and that
patients with diagnosed breast cancer have more breast volume asymmetry,
as measured from mammograms, than age-matched healthy women," write
Diane Scutt, from the University of Liverpool, UK, and colleagues.
"Symmetrical breast development may well be an indicator of an
individual's ability to tolerate 'disruptive' hormonal variation whilst
maintaining developmental stability.... It would be an important advance
if additional variations in the normal mammogram, that is breast
asymmetry, could be used to help predict the possibility of developing
breast cancer, particularly in high risk individuals."
The investigators compared breast asymmetry in 252 asymptomatic women
who had normal mammograms but went on to develop breast cancer, with
that in 252 age-matched healthy control women whose mammograms were also
normal and who remained free of cancer during the study period.
Compared with the control group, the group that went on to develop
breast cancer had more breast asymmetry (absolute asymmetry odds ratio,
1.50 per 100 mL; 95% confidence interval (CI), 1.10 - 2.04; relative
asymmetry, 1.09; 95% CI, 1.01 - 1.18), increased incidence of family
history of breast cancer, lower age at menarche, later menopause, later
first pregnancies, and a higher frequency of high-risk breast parenchyma
types.
Breast asymmetry, height, family history of breast cancer, age at
menarche, parenchyma type, and menopausal status were significant
independent predictors of breast cancer, based on conditional logistic
regression analysis. When age at menopause was included in the model for
the subgroup of postmenopausal women, absolute breast fluctuating
asymmetry (FA) and relative breast FA remained significant predictors.
"Breast asymmetry was greater in healthy women who later developed
breast cancer than in women who did not," the authors write.
"Asymmetrical breasts could be reliable indicators of future breast
disease in women and this factor should be considered in a woman's risk
profile."
The authors report no competing interests.
Breast Cancer Res. 2006;8:R14
Learning Objectives for This Educational Activity
Upon completion of this activity, participants will be able to:
* Describe fluctuating asymmetry of sexual traits and their
clinical significance.
* Identify the risk for breast cancer associated with asymmetry of
breast tissue.
Clinical Context
FA describes small, random deviations from perfect body symmetry that
affect all species to some degree. The authors of the current study note
that sexually selected traits have the highest values for FA of all
parts of human anatomy. Previous research has suggested that large
breasts have higher degrees of FA than small breasts, and breast FA is
higher among nulliparous women. In addition, breast FA can predict
fecundity.
Breast asymmetry may also be linked to a higher risk for breast cancer.
The authors of the current study performed a case-control review to
assess this possible risk.
Study Highlights
* The authors focused on a cohort of 12,942 asymptomatic women who
underwent mammography between 1979 and 1986. 252 of these women who
developed breast cancer were compared with 252 age-matched controls.
* The main study outcome was the difference in breast volume
asymmetry between women with breast cancer and control subjects. Breast
cancer volume was calculated from a standard formula of mammographic
findings, and physicians who read mammograms were blinded from the
patients' cancer status.
* Mean age at breast cancer diagnosis was 55 years, and the mean
interval between mammography and tumor presentation was 6.4 years.
* In general, the left breast was larger than the right breast.
The mean ratio of left:right breast volume was 1.04.
* Breast volume asymmetry was associated with an increased risk of
cancer. The median breast volume asymmetry among women with cancer was
63.17 mL compared with a median of 52.99 mL in the control group. This
result was unchanged after accounting for breast size.
* Whether left or right breasts were larger did not affect the
risk of cancer.
* There was no change in the study's main outcome on logistic
regression analysis, including subjects' age at menopause and multiple
breast cancer risk factors. For each 100-mL increase in breast volume
asymmetry, the relative odds of breast cancer increased by 1.50. Each 1%
increment of FA increased the risk of cancer by a factor of 1.09.
* For the cohort as a whole, breast asymmetry was not related to
the duration between mammography and the diagnosis of cancer. However,
among women who died from breast cancer, higher degrees of FA were
associated with a shorter duration between mammography and tumor
presence.
Pearls for Practice
* Sexual characteristics are the parts of human anatomy most
likely to demonstrate FA. Breast asymmetry is more common among women
with large breasts and among nulliparous women.
* The current study demonstrates that breast asymmetry is
positively associated with breast cancer, regardless of breast size, the
laterality of asymmetry, or the age of menopause.
Top of Form
Bottom of Form
Esther G
***********************************************
To temporarily stop your subscription: set lactnet nomail
To start it again: set lactnet mail (or digest)
To unsubscribe: unsubscribe lactnet
All commands go to [log in to unmask]
The LACTNET email list is powered by LISTSERV (R).
There is only one LISTSERV. To learn more, visit:
http://www.lsoft.com/LISTSERV-powered.html
|
