The Pill and Cancer

Does the combined oral contraceptive pill cause cancer?

Cancer

The results of a recent large UK study indicate that oral contraception is not associated with an overall increased risk of cancer. There was a statistically significant reduction in all cancers in older women who had ever used oral contraceptives.

Gynaecological cancer

Combined oral contraceptive pills (COCPs) reduce the risk of endometrial and ovarian cancer. When compared with women who have never used COCs, COC users are 50% less likely to develop ovarian cancer.

COC use for approximately 3 years reduces a woman’s risk of developing endometrial cancer by about 50%.

Use of COCs for 10 years or more reduces a woman’s risk of developing such cancers by 80%.

The protective effect lasts for up to 20 years after cessation of COCs.

Breast cancer

There is debate as to whether use of the COC increases the risk of breast cancer.  A large study in published in 1996 found a small increased risk for current users compared with women in the population who are not taking or have not taken the pill.

Another large study published in 2002 found no increased risk, regardless of duration of use, age at commencement of taking the pill, or family history.

A family history of breast cancer is classified as World Health Organisation Medical Eligibility Criteria WHO Category 1 (safe to use) for COC use.

Cervical cancer

A reanalysis of data from relevant worldwide studies to examine the relationship between cervical cancer and the use of hormonal contraceptives found that the risk of cervical cancer in women using the combined oral contraceptive pill for 10 years (from around ages 20-30 years) was increased.

The incidence of invasive cervical cancer by age 50 in these women is increased, from 3.8 to 4.5 per 1000 in developed countries and from 7.3 to 8.3 in 1000 in less developed countries. This risk declines after use ceases.

Liver cancer

There is a 4-fold increase in the risk of liver cancer in long-term COC users. This adds few additional cases, as the background risk is extremely low.

There does not seem to be an additional increased risk, above their existing risk, in women with chronic hepatitis.

Colorectal (Bowel) cancer

Studies that have analysed the risk of colorectal cancer with COC use have indicated an overall reduced risk of these cancers.

The use of combined oral contraceptives in women with a history of cancer:

Breast cancer

Breast cancer is a hormonally sensitive tumour and the prognosis of women with current or recent breast cancer may worsen with use of COCs.

Cervical cancer

In women who have been diagnosed with changes on their cervix or with cervical cancer (awaiting treatment), COC is category 2 (the benefits outweigh the risk).

Ovarian cancer

Can be used, no contraindication. WHO category 1

Endometrial cancer

Can be used, no contraindication. WHO category 1

Gestational trophoblastic neoplasia (Abnormal growth in the cells of very early pregnancy)

Women are advised against the use of hormonal contraception until serum concentrations of human chorionic gonadotrophin (HCG - one of the pregnancy hormones) are normal.

Liver cancer

Should not be used. WHO category 4.

References

Hannaford PC, Selvaraj S, Elliott AM, Angus V, Iversen L, Lee AJ. Cancer risk among users of oral contraceptives: cohort data from the Royal College of Practitioner’s oral contraception study. BMJ online doi:10.1136/bmj.39289.649410.55 Cited 12 Sept 2007

FFPRHC Clinical Guidance: First prescription of combined oral contraception July 2006 (updated January 2007)

Hatcher R, Nelson A. Combined hormonal contraceptive methods. In Contraceptive technology. 18th edn. New York: Ardent Media, 2004.

Breast cancer and hormonal contraceptives: collaborative reanalysis of individual data on 53 297 women with breast cancer and 100 239 women without breast cancer from 54 epidemiological studies. Collaborative Group on Hormonal Factors in Breast Cancer. Lancet 1996; 347(9017): 1713-27.

Marchbanks P et al. Oral Contraceptives and the risk of breast cancer. New England Journal of Medicine 2002:346:2025-32

World Health Organization. Medical Eligibility Criteria for Contraceptive Use. 3rd edn. Geneva, Switzerland: World Health Organization, 2004. http://www.who.int/reproductive-health/publications/mec/

International Collaboration of Epidemiological Studies of Cervical Cancer. Cervical cancer and hormonal contraceptives: collaborative reanalysis of individual data for 16573 women with cervical cancer and 35509 women without cervical cancer from 24 epidemiological studies. Lancet 2007;370:1609-21

Scalori A, Tavani A, Gallus S et al. Oral contraceptives and the risk of focal nodular hyperplasia of the liver: a case-control study. American Journal of Obstetrics & Gynecology 2002; 186(2): 195-7

Fernandez E, VecchiaCL, Balducci A, Chatenoud L, Franchesci S, Negri E. Oral Contraceptives and colorectal cancer risk: a meta-analysis. Br J Cancer 2001; 84: 722-727

For more information

Contact the FPNSW Healthline on 1300 658 886 or email us.

DISCLAIMER

The information in this Factsheet has been provided for educational purposes only. FPNSW has taken every care to ensure that the information is accurate and up-to-date at the time of publication. Individuals concerned about any personal reproductive or sexual health issue are encouraged to seek advice and assistance from their health care provider or visit a FPNSW clinic.

Reviewed July-09