Wednesday, October 14, 2009

An update on breast cancer and contraceptive pills

The risk of breast cancer among women who take oral contraceptive pills (OCP) has been studied for a long time. The results of the studies are still controversial—some point to an increase while others to no effect.


Estrogen and breast cancer

It is known fact that the breast tissue is affected by hormones, specifically by estrogen. A very practical way to understand this is when your breasts enlarge just before menstruation and during pregnancy. In both occasions, your hormones are at higher levels than the usual.

The Women’s Health Initiative (WHI) study caused the great turnaround in the use of hormone replacement for menopausal women because it showed that the use of a combination estrogen and progestin replacement in these women caused an increase in the risk of breast cancer. However, the result among reproductive age group (read: those still menstruating) who take OCP (also a combination of estrogen and progestin) is not as clear cut as in these menopausal women.

The conflicting results

• OCP increases breast cancer. A Scandinavian study reported in the journal Cancer Epidemiology, Biomarkers and Prevention (Vol.11: 1375-1381) was a prospective study where women who used OCP were followed up from 1991 to1999 and the number of those who developed breast cancer was compared to those who did not. The results showed that breast cancer risk was increased by 60 per cent for women who were still taking the pill while those who stopped for a year or more only had a 20 per cent risk.

• OCP did not increase breast cancer. However, another study by the National Institute of Child Health and Human Development (NICHD) called Women's Contraceptive and Reproductive Experience (Women's CARE) done between 1994 and 1998 showed there was no increased risk of breast cancer in current or former users of birth control pills.

Other factors which cause breast cancer in OCP takers

• Family history. In a study in the Journal of the American Medical Association, the result showed a higher risk (up to 11 times) among OCP takers with a strong family history of breast cancer. However, it should be noted that more than half of breast cancer cases occur in those with no family history of the disease.

• Genetics. A study reported in the Journal of the National Cancer Institute (Vol. 94, No. 23: 1773-1779) looked at the link between OCP and breast cancer in women with BRCA1 and BRCA2 mutations. A mutation is a random change in the genetic material. There are two types of mutations in this breast cancer gene called BRCA1 and BRCA2. The study reported that OCP increased breast cancer risk for women with mutations in BRCA1 but not in those with mutations in BRCA2. Among those with no mutations, there seem to be a very low risk.

• Age. There is a study which showed an increased risk of breast cancer in women 45 years and older who were still taking the pill. The probable cause in these women could be that the older OCP preparations had a significantly higher dose of estrogen. In addition, breast cancer is a disease of older women, with more than half in their 60s.

• Length of use. There seem to be an increase risk among those who have taken OCP for long periods of time but the exact length was not specified. Some research have found that if you have stopped taking OCP for at least 10 years, your breast cancer risk returned to the same level as those who have never taken the pills.

Should I take contraceptive pills?

Yes, you can still take the pill, but with caution to those who have a strong family history of breast cancer, found to have mutations in BRCA1 gene and aged 40 or more.

However, the final decision on whether you should take the pill will rely on your own reasons for taking it. OCP by itself will not cause breast cancer, but MAY increase the RISK of developing it. This article is for informational purposes only for a more thorough discussion with your health provider. read the original complete article here

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