Progesterone use may increase risk for thyroid cancer in women with infertility
Click Here to Manage Email Alerts
Among women with infertility, those using progesterone may have a higher risk for developing thyroid cancer compared with those who have never used progesterone, although the risk remains low, according to study results.
In an analysis of data from more than 140,000 women with infertility living in Denmark from 1995 to 2017, those who ever used progesterone were more likely to develop any type of thyroid cancer; however, the proportion of progesterone users who developed thyroid cancer was only 0.12%, and researchers found no other associations between fertility drugs and thyroid cancer risk.
“No marked associations were demonstrated between the ever use of clomiphene citrate, human chorionic gonadotropin, gonadotropins or gonadotropin-releasing hormone receptor modulators, and thyroid cancer,” Allan Jensen, PhD, senior researcher and group leader of lifestyle, reproduction and cancer at the Danish Cancer Society Research Center in Copenhagen, Denmark, and colleagues wrote. “However, for most specific fertility drugs, we observed a tendency toward higher rates of thyroid cancer among women who first used the fertility drug less than 5 years ago.”
Researchers conducted a retrospective population-based study of 146,024 women with infertility aged 20 to 45 years living in Denmark from 1995 to 2017. Information on infertility status and fertility drug use was collected from the Danish Infertility Cohort. Participants were followed until the occurrence of thyroid cancer, any other cancer, death, emigration, total thyroidectomy or the end of the follow-up period on Dec. 31, 2018.
Of the cohort, 88.6% used fertility drugs during the study period, and 167 were diagnosed with thyroid cancer. The median time from infertility diagnosis to thyroid cancer diagnosis was 9.1 years. Of those diagnosed with thyroid cancer, 84% had papillary thyroid cancer and 13% had follicular thyroid cancer.
After adjusting for calendar year at study entry, education level, parity status, obesity, thyroid disease and hormonal contraceptive use, no increased risk for thyroid cancer was observed for women using clomiphene citrate, human chorionic gonadotropin, gonadotropins and gonadotropin-releasing hormone receptor modulators. Women using progesterone had an increased risks for any thyroid cancer (adjusted HR = 1.63; 95% CI, 1.07-2.48) and papillary thyroid cancer (aHR = 1.66; 95% CI, 1.04-2.65) compared with those who never used progesterone.
Progesterone users had an increased risk for thyroid cancer within the first 5 years of fertility drug use compared with nonusers (aHR = 1.61; 95% CI, 1.01-2.56).
“It is also worth noting that the proportion of women who developed thyroid cancer was low in both the group of women who ever used progesterone (0.12%) and in the group of women who never used progesterone (0.11%),” the researchers wrote. “Hence, the observed association between progesterone and thyroid cancer should be supported by additional larger studies with longer follow-up time. As this study is the largest study to date, the results add further to the existing knowledge on the potential association between fertility drugs and thyroid cancer.”
Collapse
Read more about
Click Here to Manage Email Alerts