Birth Control Pills and Cancer Risk

It should come as considerable reassurance to women on oral contraceptives that a study carried out in the U.K involving 46,000 women who were followed over a period of thirty-six years showed no increased risk of breast cancer even with longer term use of oral contraceptives for eight years or greater. The results of this study were published in the February 2008 issue of the Journal of Family Practice.

This study showed that short term users of oral contraceptives (less than eight years) actually had a twelve percent lower risk of developing any type of cancer than did non-users. The association between oral contraceptives and cancer showed the greatest risk reduction for cancers of the colon, ovaries, and uterus.

Results were quite different with longer term use oral contraceptives and cancer risk. According to results of the same study published in the Journal of Family Practice, women who used oral contraceptives for eight years or more had a twenty-two percent greater risk of contracting any type of cancer when compared to non-users. The exceptions were ovarian cancer which showed a risk reduction with longer term use and breast cancer which showed no association between use of the oral contraceptives and cancer risk.

Analysis

The results of this study are consistent with several previous large studies that looked at the association between use of the oral contraceptives and cancer, although several smaller studies did show an increased risk of breast cancer with longer term use of oral contraceptives. The strength of the present study is that a large number of women (46,000) were followed over a longer time period (up to 36 years) which lends considerable credibility to the results.

Based on these results, should a woman who’s concerned about cancer risk avoid using oral contraceptives? Since oral contraceptive use over a shorter time period seems to have some protective effects particularly against ovarian, colon, and uterine cancers, there seems to be no compelling reason to discontinue oral contraceptives unless they’ve been used for longer than seven years. Preliminarily, it would seem advisable to avoid long term use of birth control pills.(eight years or greater), at least based on the results of this trial.

Of course, the safety of oral contraceptives will vary depending on an individual woman’s personal and family history. Women with a personal history of stroke, heart disease, or blood clots or who have a strong family history of breast cancer might best be advised to avoid use of oral contraceptives.

Although a strong consensus regarding the use of oral contraceptives and cancer has yet to be reached, this study does provide some reassurance that shorter term use of birth control pills may not significantly increase cancer risk.

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