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Recommendations for Contraceptive Use |
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Cervical Cancer Prevention |
Q.2. What causes most cases of
cervical cancer?
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| a) Human Papilloma virus (HPV),
a sexually-transmitted disease, is responsible for more than 90% of cervical cancer cases.
However, not all women infected with HPV will develop cervical cancer. |
a) Evidence suggests that, with
refined laboratory techniques, all cervical cancer tumors will be found to contain
HPV. However, of over 70 types of HPV, only 16 are moderately to strongly associated with
cervical cancer risk. Four types account for 75% of cancers.
- Bosch FX, Manos MM, Munoz N, Sherman
M, Jansen AM, Peto J, et al. Prevalence of Human Papillomavirus in cervical cancer: a
worldwide perspective. Journal of the National Cancer Institute 1995;87(11):796-802.
- Shah K, Howley PM. Papillomaviruses.
In: Fields BN, Knipe DM, Howley PM, et al (eds) Field's Virology, 3rd ed. Philadelphia:
Lippincott Raven Publishers, 1996, pp. 2077-101.
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| b) Consequently, behaviors which
put a woman at risk for sexually transmitted diseases also put her at risk for HPV and
therefore, cervical cancer. Behaviors which increase the chance of becoming infected with
HPV are: |
b) Research on each risk
behavior is discussed below. |
- having intercourse with many different partners or having
intercourse with a person who has intercourse with many different partners;
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- Studies have found a linear relationship between the
number of sexual partners a woman has and her chance of having an HPV infection; as well
as between male sexual behaviors and the rates of HPV infection in women in those
populations.
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- beginning to have intercourse at an early age or having a
first pregnancy at an early age (before 20 years old);
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- Studies have found that young age of first intercourse or
pregnancy increases the risk of cervical cancer. The cells on the cervix change rapidly
during adolescence, which may make the cells more vulnerable.
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- and not using barrier methods.
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- Because condoms do not cover the vulva, introitus or
scrotum, they cannot offer complete protection. However, use of barrier methods has been
associated with a reduced risk of cervical cancer.
- Coker AL, Hulka BS, McCann MF, Walton
LA. Barrier methods and cervical intraepithelial neoplasia. Contraception 1992;45(1):1-10.
- Manos M. Cervical cancer as a sexually
transmitted disease. Report of Emerging Issues in Reproductive Health Meeting, June 15,
1995. Tiberon CA, The Population Council.
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| c) Another behavior which
increases a woman's risk of cervical cancer is smoking. |
c) Cigarette smoking doubles a
smoker's risk of cervical cancer in comparison with a nonsmoker.
- Winklestein W. Smoking and cervical
cancer - current status: a review. American Journal of Epidemiology 1990;131(6):945-57.
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| d) High number of pregnancies or
live births may increase a woman's risk of cervical cancer. |
d) Several studies have found a
high number of pregnancies or live births to be a strong and important risk factor in
cervical cancer (independent of HPV infection). However, this association is not well
understood and is currently under investigation.
- Brinton LA, Hamman RF, Huggins GR,
Lehman HF, Levine RS, Mallin K, et al. Sexual and reproductive risk factors for invasive
squamous cell cervical cancer. Journal of the National Cancer Institute 1987;79:23-30.
- Schiffman MH, Bauer HM, Hoover RN,
Glass AG, Cadell DM, Rush BB, et al. Epidemiologic evidence showing that human
papillomavirus infection causes most cervical intraepithelial neoplasia. Journal of the
National Cancer Institute 1993;85:958-64.
- Madeleine M, Schwartz S, Daling J.
Risk factors for cervical cancer in young women by histologic type (abstract). American
Journal of Epidemiology 1996;143(11 Suppl);S84.
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