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Female
breast cancer
Summary:
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Caution: Preventive measures save lives across
populations, but not always for the individual.
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Regular breast screening reduces risk of mortality
in women 50-64 years of age.
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Avoidance of smoking, alcohol, and obesity reduces
new breast cancer numbers.
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Cigarette smoking
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Second
hand cigarette smoke
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Medicinal nicotine products,
electronic cigarettes
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There is strong
epidemiological and toxicological evidence that cigarette smoking
increases the risk of breast cancer.
In
New Zealand
an estimated 140 cases of breast cancer annually may be due to cigarette
smoking
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Proven to cause
breast cancer in pre-menopausal women. An estimated 70 cases a year in New
Zealand may be due to past exposure to
second hand smoke. Second hand smoke contains known carcinogens in its
smoke, and second hand smoke is recognized as a carcinogen in its own
right by the State of California.
http://repositories.cdlib.org/tc/surveys/CALEPA2005/
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No evidence of harm.
No carcinogens
present. Nicotine is not a carcinogen, but switching to nicotine means quitting
all cigarettes.
-Murray RP, Connett
Je, Zapawa LM. Does nicotine replacement
therapy cause cancer ? Evidence from the Lung
Health Study. Nic. Tob Res. 2009 11:1076-82.
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Smoking and Second-hand smoke cause
breast cancer – it’s official
A comprehensive
governmental review from California ( http://repositories.cdlib.org/tc/surveys/CALEPA2005/
) concludes exposure to second-hand smoke doubles the risk of breast cancer
under age 50. Smoking doubles the risk for women young or old. This is the
first official report to say that smoking or smoke can cause breast cancer. (For breast cancer download chapter 7 on cancer.)
How important
is this for New Zealand?
It is
estimated that smoking and second-hand smoke causes an estimated 200 new
cases of breast cancer each year in New Zealand, that is, 10%
of the new cases.
1.
Second-hand smoke causes breast cancer in younger women
Based on a
review of 14 studies, a new report concludes that second-hand smoke is a
cause of breast cancer in younger, primarily pre-menopausal women. The
report, of the (Government of) California Scientific Review Panel on Toxic
Air Contaminants, was released June 24, updating the landmark 1997
California Environmental Protection Agency report, later published by the
US National Cancer Institute.
Second-hand
smoke was found to have no effect in causing breast cancer in older,
primarily post-menopausal women.
The report
finds that in younger primarily pre-menopausal women exposure to
second-hand smoke increased the risk of breast cancer by 70%, regardless of
whether the data were complete. In studies with complete data (on
second-hand smoke in childhood, workplace and home), second-hand smoke
doubled the risk (2.2 times) compared with the risk in never-active
never-passive smoking women). Women were especially vulnerable to smoke
exposure between the time of first period and first pregnancy. Previous
research has been hampered by failure to ensure that the women in the
comparison group were never-active, never-passive smokers.
2. Smoking
causes breast cancer
Based on a
review of 13 studies, with special attention to studies with complete data,
smoking doubled the risk of breast cancer compared with never-active, never-passive-smokers.
The report concludes "the data provide support for a causal
association between active smoking and elevated breast cancer risk."
Starting to smoke at an early age or starting smoking prior to first
childbirth increased the risk in several studies reviewed. The more pack
years smoked, the greater the risk.
The effects of
direct smoking have been hidden in the past by smoking’s
protective anti-estrogen effect opposing the effect of carcinogenic gases
in smoke, and by the lack of a truly smokefree
group of women for comparison.
3. Smoking
and smoke – an important cause of breast cancer in New Zealand
Second-hand
smoke and female breast cancer in New Zealand. - over 70 cases a year from past
exposure
Second-hand
smoke from all sources in the past cause an estimated one-sixth of new
cases of breast cancer in the childbearing age group. Applying the method
of Woodward & Laugesen, Tobacco
Control SHSdeaths.pdf, to the 621
cases of breast cancer in women under age 50 in 2003 (www.nzhis.govt.nz), we estimate over 70
new cases of breast cancer annually are due to past second-hand smoke
exposures, with some reduction in future now that smoking is banned indoors
at work.
Direct smoking and female breast cancer in New Zealand. – 140 cases a year from past
smoking
NZ Health
Information Service registered 2297 new cases of breast cancer in 2003. A
breast cancer takes an average 12 years (range 6-20 years) to reach 1 cm
diameter. (Tubiana 1991) In 1990, 27% of New Zealand women were regular smokers. On this
basis, smoking causes an estimated 140 cases of breast cancer annually.
Preventing
breast cancer
1) The smokefree homes campaign, on
top of the legislation now enforcing smokefree
indoor workplaces, could prevent up to 17% of breast cancer in women under
age 50 if no-one (and no-one else) smokes inside their home.
2) The comprehensive smoking control programme. Elimination
of smoking could prevent up to 200 cases of new cases of female
breast cancer annually. Strong, innovative policies are needed to further reduce smoking and
addiction. For example, see a proposed national nicotine policy to reduce
the nicotine in cigarettes at: www.endsmoking.org.nz/lowernic.htm
3) Exercise from moderate to
vigorous can prevent 20-30% of breast cancer, requires 30-60 minutes per
day, and particularly benefits women over the age of 50.
4) The national breast screening
programme for women over the age of 50, does
not prevent breast cancer but offers free screening to detect cancer
earlier, to prevent several hundred deaths annually. Screening benefits
participating women regardless of smoking habits and past smoke-exposure.
SmokeLess New Zealand supports action points for health
workers such as:
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Mention breast cancer risk for mothers and
daughters when promoting smokefree homes.
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Mention breast cancer when talking to women
smokers about quitting.
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Promote smokefree
lifestyles as part of breast health and screening.
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Include breast cancer risk in health education
materials on smoking and smoke.
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based on Murray Laugesen. NZ Smoke-free e-News 30 June
2005. www.healthnz.co.nz
Dr Murray Laugesen QSO chair; Prof Ross McCormick, Sir John Scott KBE, Trish
Fraser MPH, Dr Marewa Glover, Trustees
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