NEW YORK (Reuters Health) - Surviving breast cancer is no guarantee
that a new cancer won't appear in the other breast. However, research now
suggests that women can build their own personal armor to at least partially
protect themselves from this occurring.
All it takes, says Dr. Christopher I. Li, is to "stay at a normal weight,
don't smoke, and drink in moderation."
The research, headed up by Li at the Fred Hutchinson Cancer Center in
Seattle, Washington, suggests that obesity, smoking and drinking too much
are all risk factors for breast cancer in the opposite breast -- also called
the "contralateral" breast -- of women who've had an "estrogen
receptor-positive invasive breast cancer."
That's because estrogen can fuel these tumors' growth, and both fat tissue
and excessive alcohol use directly increase estrogen levels in the body, Li
and his team propose. They believe that smoking contributes to the risk
because of all the cancer-causing substances one inhales when smoking.
Until now, there haven't been many studies regarding ways that women could
protect themselves from second breast cancers, according to the report in
the September 8th online issue of the Journal of Clinical Oncology.
The new study included 365 women with a first estrogen receptor-positive
breast cancer and a second contralateral cancer and 726 control subjects. By
reviewing medical charts and interviewing the women directly, the
researchers determined body mass index (BMI) and alcohol and tobacco use.
BMI is an estimate of a person's relative body fat calculated from her
height and weight.
Compared with normal weight women, those who were obese were almost half
again - by 40% -- as likely to develop a contralateral breast cancer.
Consumption of 7 or more alcoholic drinks per week nearly doubled the risk
compared with no alcohol use. Findings were similar for current smoking.
Women who both smoke and drink following diagnosis of the first cancer had
an even greater risk of a second cancer. The study showed that consuming 7
or more alcoholic drinks per week coupled with current smoking increased the
odds of contralateral breast cancer more than 7-fold.
In a related editorial, Dr. Jennifer A. Ligibel, from the Dana-Farber Cancer
Institute in Boston, points out that the study by Li and his team took place
before use of hormonal therapy for estrogen receptor-positive breast cancer
became routine. Therefore, a more modern study examining the effect of
modifiable lifestyle factors should involve patients treated according to
current guidelines.
SOURCE: Journal of Clinical Oncology, September, 2009.
