Smoking increases risk cervical cancer

By Martha Kerr

NEW YORK (Reuters Health) – Cigarette smoking increases a
woman’s risk of developing cancer of the cervix, and the risk
increases with the number of cigarettes smoked per day and with
the younger the age at which smoking began, according to a new
report.

Researchers with the International Collaboration of
Epidemiological Studies of Cervical Cancer evaluated data from
23 studies on the effects of smoking on cervical cancer risk,
involving 23,017 women who were initially free of cervical
cancer.

Dr. Amy Berrington de Gonzales, of Cancer Research UK in
Oxford, and colleagues report in the International Journal of
Cancer that current smokers have a 60 percent greater risk of
cervical cancer than women who never smoked.

The analysis found no association between smoking duration
and risk of cervical cancer, but did show a correlation with
age of starting smoking.

“It is not clear why this association was present,”
Berrington said in an interview with Reuters Health. “One
possible explanation is that duration of smoking was reported
less accurately than age at starting smoking, and age at
starting smoking is acting as a surrogate for duration of
smoking, i.e. earlier age at starting smoking is a marker of
longer duration.”

Eight of the 23 studies included data on cervical infection
with human papilloma virus or HPV, which has been linked to
most cases of cervical cancer. In these studies, women who
tested positive for HPV had a risk of cervical cancer almost
two-fold higher than HPV-negative women.

These results confirm that smoking is a risk factor for
cervical cancer, Berrington noted, “as the association was
present also in women who were HPV-positive, strongly
suggesting that the association is not just due to confounding
between sexual behavior and smoking.”

SOURCE: International Journal of Cancer, March 15, 2006.