Feeding & Breast Cancer
logical that these topics should be related, but is there really a link
between breast cancer risk and breast feeding? Many studies seem to say
that there is. There are plenty of questions and some very powerful answers
available in the literature.
breast feeding have any effect on my risk of developing cancer?
Does breast feeding have any effect on the baby's
risk of developing cancer?
Does it make any difference how long I breast feed?
Is it true that some women develop masses in their breast
due to breast feeding?
breast feeding have any effect on my risk of developing cancer?
There are many studies -- most of which contradict
one another -- on whether breast-feeding cuts your risk of breast cancer.
a study published in the journal Cancer, researchers compared the
lactation histories of 446 South African women with breast carcinoma with
those of 1,471 women admitted to hospitals with conditions unrelated to
breast cancer. The study found no connection between breast cancer risk
and the number of children breast fed, the length of time mothers breast
fed, or the mother's age at first lactation.
December 1997 issue of the American Journal of Epidemiology provides
a study involving 1,313 women which showed that premenopausal women had
a 50 percent lower risk of breast cancer if they had breast-fed for at
least 20 months, compared to women who had at least one baby and had not
the July 1999 issue of the American Journal of Epidemiology a study
found that women who had breast fed for a little as two weeks showed a
reduced risk of breast cancer up to 50 years later.
study recently reported in the International Journal of Epidemiology
followed two groups of women from North Carolina. The study compared 751
women diagnosed with breast cancer, and 742 who didn't have it. Of those
who had cancer, 310, or 41.3 percent, had breast-fed. Of those who didn't
have cancer, 356, or 47.9 percent had breast-fed -- leading to a 30 percent
reduced chance of breast cancer if you breast-fed. Studies like this make
me shake my head in wonder. The results are valid. There really is a 30%
lower risk of being in the breast cancer group if you breast fed, but
41.3 percent of the cancer group had breast fed... what happened to their
is that taken with all of the various genetic and environmental factors
that influence a women's risk of developing breast cancer - breast feeding
certainly does not increase the risk -- and long term breast feeding may,
in fact, reduce the risk of developing breast cancer.
for women who have been diagnosed with breast cancer is that breast feeding
seems to increase the speed at which a tumor grows. Some advocates of
breast feeding recommend breast feeding anyway. The bulk of the professional
literature tends to discourage breast feeding for women who have breast
cancer or who have had breast cancer.
breast feeding have any effect on the baby's risk of developing cancer?
A 1988 article in the Lancet showed that children who are artificially
fed or breast fed for only 6 months or less, are at an increased risk
of developing cancer before age 15. The cancer risk of bottle-fed children
was 1-8 times that of children who had been breast fed for longer than
6 months. The risk for babies breast fed for a shorter time was 1-9 times
that of long- term breast feeders.
and Medicine & Pediatric Oncology have both featured studies
that show a 25% lower risk of developing breast cancer for women who were
breast fed instead of bottle-fed as infants, even if only for a short
time. This effect was true for both premenopausal and postmenopausal breast
it make any difference how long I breast feed?
In the American Journal of Epidemiology (1996) a study of Mexican
women associated less time breast feeding with increased breast cancer
study recently published in the International Journal of Epidemiology
counters the findings of previous studies that the longer you breast-fed,
the more you cut your breast-cancer risk. This study found a 30 percent
reduction in breast cancer risk for women who had breast fed their babies
for any amount of time. The author stated, "Breast cells become more mature
once they've undergone their natural function; the breast is carrying
out the function it was made to do."
Chinese study showing an inverse relation between length of breast-feeding
and breast cancer revealed that the women breast-fed on average for three
years. In June 1998 Newsweek reported that only 38% of American
moms even try breastfeeding and only 15% nurse for one year. This is one
of the lowest rates in the world. The American Academy of Pediatrics and
the American Dietetic Association urge mothers to nurse for at least 12
theories for the causes of breast cancer include the strong role of ovarian
hormones, estrogen and progesterone. A study in the British Journal
of Cancer reported that the number of children breast-fed did not
decreased the risk of breast cancer, but longer total duration of breast-feeding
provided a stronger protective effect.
delays the onset of ovulation after pregnancy, thus reducing a woman's
overall exposure to the hormone. It would be logical that longer breast-feeding,
which depresses hormone levels for longer periods of time, would be more
effective in preventing breast cancer.
it true that some women develop masses in their breast due to breast feeding?
The answer to this one is yes. A small percentage of nursing mothers develop
obstructions in the milk ducts known as "galactoceles." They can occur
while you are nursing, but appear more commonly after lactation has stopped,
when the milk is allowed to stay in the breast.
self exam may reveal smooth, movable, sometimes tender masses. These may
well be localized collections of milk, but should be followed up on by
may recommend aspiration which will both diagnose and cure the condition.
Fluid milk is removed when the aspiration is performed during or soon
after lactation. If the lesions are older and it has been a while since
you stopped nursing the milk may have become a thicker, cheesy material.
Several aspirations may be necessary to completely drain the duct. Ice
packs and a well-fitting support bra are helpful.
is not usually necessary. Galactoceles may be difficult to distinguish
from other fat-containing breast lesions on mammography. There is a characteristic
mammographic appearance which may show layering of fat density over water
no known relationship between galactoceles and fibrocystic
breast disease. Surgery is rarely required.
updated May 1, 2017
on the Web:
- Breast Cancer and Pregnancy
Feeding & Breast Cancer Risk