Pill with high potency progestogen protects against cancer
BMJ 2002; 324 doi: https://doi.org/10.1136/bmj.324.7329.69 (Published 12 January 2002) Cite this as: BMJ 2002;324:69
Oral contraceptives with a higher progestogen potency lead to a greater reduction of risk of ovarian cancer than those with lower progestogen potency, says a new study in the US Journal of the National Cancer Institute (2002;94:32-6). This was regardless of the oestrogen content in the pills and how long they were used for.
The study, from Duke University Medical Centre in Durham, North Carolina, supports claims that biological effects of progestogen may in themselves help to protect women, rather than just the fact the pill inhibits ovulation, which has for some time been believed to reduce risk.
The researchers say they hope that further research will lead to the development of other protective agents, in addition to progestogen, which could be formulated into a more powerful pharmaceutical strategy against ovarian cancer.
The study's participants were 390 women with epithelial ovarian cancer and 2865 controls between 20 and 54 years old, who were identified from the cancer and steroid hormone study. Dr Joellen Schildkraut, principal author of the study, said that while high potency progestogen pills protect against ovarian cancer, it is possible they could increase the risk of certain types of breast cancer in younger women.
Her report also listed a number of limitations of the study, including the fact that the women studied “were relatively young compared with women in the general population who develop ovarian cancer.” She also said it was possible that the use of oral contraceptives might have been miscalculated, particularly because specific formulations and doses of the drugs used were reported retrospectively.
Dr Anne Szarewski of Britain's Imperial Cancer Research Campaign said that the study was interesting but not conclusive. The injectable contraceptive Depo-Provera has not been shown to protect against ovarian cancer, despite the fact that it contains progestogen at levels much higher than those found in any contraceptive pill, she said.