Young women who smoke may have an increased risk of a common
type of breast
cancer, according to a new study.
deadly in women with breast cancer
Researchers found that women between 20 and 44 years old who
had smoked a pack of cigarettes per day for at least 10 years were 60% more
likely than those who smoked less to develop so-called oestrogen
receptor-positive breast cancer.
Smokers were not more likely to develop a less common form
of breast cancer known as triple-negative breast cancer, which tends to be more
aggressive."I think that there is growing evidence that breast cancer is
another health hazard associated with smoking," Dr Christopher Li told
Li is the study's senior author from the Fred Hutchinson
Cancer Research Centre in Seattle. Previous research has found links between
smoking and breast cancer, Li and his colleagues note in the journal Cancer. The studies looking at breast
cancer among younger women have produced conflicting results, however.
They also say there are still questions about whether
smoking is linked to an increased risk of some types of breast cancer but not
others."I think there is a growing appreciation that breast cancer is not
just one disease and there are many different subtypes," Li said. "In
this study, we were able to look at the different molecular subtypes and how
smoking affects them. "He and his team analysed data from young women in
the Greater Seattle area who were diagnosed with breast cancer between 2004 and
2010. Of those women, 778 were diagnosed with the more common oestrogen
receptor-positive type and 182 had the less common but more aggressive
The researchers also included information from 938
cancer-free women for comparison.
According to the National Cancer Institute, about one in
every eight American women will eventually develop breast cancer – but the risk
is lower at younger ages. Only about one in every 227 30-year-old women – or
less than half a percent of them – will develop breast cancer before the age of
40, for example.
In this study, young women who had smoked at some stage were about
30% more likely to develop any type of breast cancer, compared to women who had
When the researchers looked at each type of breast cancer
separately, there was no link between smoking and triple-negative breast
cancer. But women who were recent or current smokers and had smoked for at least
15 years were about 50% more likely to have oestrogen receptor-positive breast
cancer, compared to women who had smoked for fewer years.
Smoking role not yet
And those women who reported smoking at least one pack a day
for 10 years were 60% more likely to have that type of cancer, compared to
It could be that some of the substances found in cigarettes
act like oestrogens, which would promote oestrogen receptor-positive breast
cancer, the researchers write."There are so many different chemicals in
cigarette smoke that can have so many kinds of effects," Li said.
Geoffrey Kabat cautioned that some of the effects found in
the new study are small and not clear-cut.
Kabat was not involved with the study, but has researched
the effects of smoking on breast cancer risk. He is also an epidemiologist at
the Albert Einstein College of Medicine of Yeshiva University in Bronx, New
He told Reuters Health the findings of previous studies are
not "very consistent". "We know smoking is bad for you and the
earlier you smoke and the more often you smoke the worse off you're going to be
in terms of many outcomes, but the role of smoking in breast cancer is not clear,"
Kabat said. "There may be something going on and it may be a modest effect
in some subgroups."
smoking harms your breasts
Smoking increases breast cancer after menopause
grows, linking smoking to breast cancer