Fertility Drugs, Ovarian Cancer: No Link
Fertility Drugs Appear Safe, Study Says
By
Salynn Boyles
WebMD Health News
Reviewed By
Louise Chang, MD
Feb. 5, 2009 -- Findings from a newly published study should reassure women
who have been treated for infertility and worry that the drugs they took will
increase their risk for ovarian cancer.
The study found little association between the use of drugs like Clomid and
the cancer.
There has long been concern that the ovulation-stimulating and
ovulation-regulating drugs used to treat infertility raise ovarian cancer risk.
Several small studies conducted in the 1990s suggested that they do, but more
recent studies failed to show an association.
Now the largest, most rigorously designed trial ever to address the question
shows "no convincing association" between fertility drug use and ovarian
cancer.
Women in the study were followed for an average of 16 years after treatment.
Researchers say longer follow up is needed to rule out a strong link between
the fertility drugs they took and ovarian cancer.
Their average age at follow-up was just 47, and the peak age for ovarian
cancer is the early 60s.
But lead researcher Allan Jensen, PhD, of the Danish Cancer Society, tells
WebMD that the new findings should be viewed as reassuring.
"If there were a strong association we would definitely expect to see it by
now, and we don't," he says. "But we will certainly continue to follow these
women."
Fertility Drugs, Ovarian Cancer
Jensen and colleagues reviewed the medical records of 54,362 infertile women
treated at fertility clinics in Denmark between 1963 and 1998. During
follow-up, 156 of the women were diagnosed with ovarian cancer.
After adjusting for risk factors associated with the cancer, the researchers
examined the impact of four different fertility drugs on ovarian cancer risk:
clomifene citrate (Clomid, Serophene); gonadotropins; human chorionic
gonadotropin; and gonadotropin-releasing hormone.
The found no overall increased risk for the cancer related to use of any of
the fertility drugs.
In addition, no treatment-related increase in risk was seen among women who
had undergone 10 or more treatment cycles and women who never became pregnant
-- two groups that have been believed to be especially vulnerable.
A small increase in risk for one of the most deadly types of ovarian cancer
was seen in women who took Clomid or Serophene, but Jensen says that this was
probably a chance association.
The study appears in the latest issue of the journal BMJ Online
First.
Infertility Increases Ovarian Risk
Studying the impact of fertility drugs and ovarian cancer is complicated by
the fact that infertile women and women who've never had children already have
a higher than average risk for the cancer, says research Penelope Webb, PhD, of
Australia's Queensland Institute of Medical Research.
She tells WebMD that one of the greatest strengths of the new study is that
researchers went to great lengths to control for this.
In an editorial published with the study, Webb writes that the findings
provide further evidence that fertility drugs have no great impact on ovarian
cancer risk.
"Some women who take fertility drugs will inevitably develop ovarian cancer
by chance alone, but current evidence suggests that women who use these drugs
do not have an increased risk of developing ovarian cancer," she writes.
Earlier findings by the Danish group involving the same cohort of infertile
women also suggest no link between fertility drug use and an increased risk for breast cancer, thyroid cancer, and malignant melanoma, Jensen says.
SOURCES: Jensen, A., BMJ Online First, Feb. 5, 2009. Allan Jensen, PhD, Danish Cancer Society, Institute of Cancer Epidemiology,
Copenhagan, Denmark. Penelope M. Webb, PhD, senior research fellow, Queensland Institute of
Medical Research, Royal Brisbane Hospital, Brisbane, Australia. "Risk of Breast Cancer after Exposure to Fertility Drugs," Cancer
Epidemiology, Biomarkers and Prevention, July 1, 2007.
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