A report assessing results from 52 studies has found that postmenopausal use of hormone replacement therapy significantly increases the risk of ovarian cancer, even with less than 5 years of hormone therapy use.
Current guidelines for the use of hormone replacement therapy are varied:
– European drug regulation guidelines: No mention of ovarian cancer
– FDA: No mention of ovarian cancer
– UK drug regulation guidelines: Ovarian cancer may be increased by long-term use
– WHO: Insufficient evidence for risk of ovarian cancer
A study published in the Lancet conducted by the International Collaborative Group on Epidemiological Studies of Ovarian Cancer and the University of Oxford, has reported on data from 21 488 postmenopausal women with ovarian cancer, derived from 52 studies on hormone replacement therapy. The study aimed to assess the potential link between hormone replacement therapy and ovarian cancer, particularly in regards to short-term use, which is currently common practice for hormone replacement therapy.
The study found a statistically significant risk of ovarian cancer in those who used hormone replacement therapy compared with those who did not. The results of the study suggest a causal link between hormone replacement therapy and ovarian cancer. The results also suggest that use of hormonal therapy for 5 years (starting at approximately age 50), would result in approximately one more ovarian cancer per 1000 users, and one more ovarian cancer death per 1700 users. When calculating for 10 years of hormonal therapy use, the result would equate to one more ovarian cancer case per 600 users, and one more ovarian cancer death per 800 users.
This increased risk was only noted for the two most common types of ovarian cancer; serous and endometrioid ovarian cancers. An important finding of the study was that the risk of ovarian cancer was increased even in women who had used hormone replacement therapy for less than 5 years. There was a strong association between risk and more recent use, even in women who had used hormonal therapy for less than 5 years. The risk, however, decreased based on the amount of time since the use of hormone therapy was stopped. The increased risk was seen for both main types of hormonal replacement therapy, estrogen only or estrogen and progesterone. The results of the study were not affected by age, body size, past use of oral contraceptives, hysterectomy, alcohol or tobacco use, or family history of either breast or ovarian cancer. The authors suggest that due to the pattern of use of hormonal therapy, which is usually less than 5 years, the study provides evidence that current guidelines should be amended.
European Medicines Agency. “Guidelines on clinical investigation of medicinal products for hormone replacement therapy of oestrogen deficiency symptoms in postmenopausal women.” www.ema.europa.eu/docs/en_GB/document_library/Scientific_guideline/2009/09/WC500003348.pdf. (accessed Jan 1, 2014).
US Food and Drug Administration. “Estrogen and estrogen with progestin therapies for postmenopausal women.” www.fda.gov/Drugs/DrugSafety/InformationbyDrugClass/ucm135318.htm. (accessed Jan 1, 2014).
Medicines and Healthcare products Regulatory Agency (MHRA). “Hormone-replacement therapy: safety update. UK Public Assessment Report.” www.mhra.gov.uk/home/groups/pl-p/documents/websiteresources/con2032228.pdf. (accessed Jan 1, 2014).
International Agency for Research on Cancer. “Monograph Volume 91: combined estrogen-progestogen contraceptives and combined estrogen-progestogen menopausal therapy.” International Agency for Research on Cancer, Lyon, France; 2007
“Menopausal hormone use and ovarian cancer risk: individual participant meta-analysis of 52 epidemiological studies. Collaborative Group on Epidemiological Studies of Ovarian Cancer” LancetPublished Online February 13, 2015, http://dx.doi.org/10.1016/S0140-6736(14)61687-1
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