Most tumors, when discovered, are dealt with quickly — through removal, chemotherapy, or otherwise.
But uterine fibroids, benign in all but the rarest of circumstances, present an opportunity for researchers.
“Usually, when you find a tumor, you want to take it out,” said Donna Baird, Ph.D., principal investigator, epidemiology, for the National Institute of Environmental Health Sciences. “Fibroids are one of the rare times when you can look at tumor growth and describe it.”
Baird, a guest lecturer at the CTSI Seminar Series on Women’s Health on Sept. 30, shared her research on uterine fibroids, outlining her current work and offering new directions for future studies.
What we know
Uterine fibroids are smooth muscle tissue tumors which grow in the uterus of a majority of women in the middle to late reproductive years. They are extraordinarily common — in the United States, 70 percent of white women and 80 percent of African American women develop uterine fibroids at some point — and most of them are asymptomatic, with many women never realizing that they have them.
But some fibroids do grow to the point where treatment is necessary. Historically, uterine fibroids have been the leading cause of hysterectomies in the United States.
“So it’s a major health problem,” said Baird.
There are a handful of established risk factors — women in their middle-to-late reproductive years are most likely to develop fibroids, African Americans are at higher risk than white Americans, and early age of menarche and nulliparity also increase risk. But since uterine fibroid development is so common, simply measuring incidence may not provide much information about preventing development of disabling symptoms that are treated with major medical procedures, said Baird.
So, in a recent study, Baird’s group instead decided to focus on fibroid growth, enrolling 116 pre-menopausal women with clinically-relevant fibroids and measuring fibroid growth via MRIs over the course of a year.
While there was a wide variety of fibroid growth and shrinkage during the study period, the fibroids in the majority of women grew only a small amount — an average of 9 percent every six months.
Baird also found in a later study that about a third of fibroids seen at the beginning of pregnancy actually disappeared by 4 months after birth, consistent with their hypothesis that parity is protective because tumor tissue will be cleared during the process of postpartum uterine remodeling.
Since the publication of the growth study, Baird has begun a new study which involves a cohort of 1,696 African American women aged 23-34 in the Detroit area. Her group is following the women for five years and screening with ultrasound every 20 months to identify new fibroids and follow growth of already existing fibroids. They are testing whether Vitamin D could be a preventative in terms of fibroid development.
“If it were found to be effective, it would be wonderful — it’s cheap and it’s easy,” said Baird. “Of course, we have lots of other questions. For example, there’s an interesting hypothesis that heavy bleeding actually causes fibroids.”
They’re also hoping to identify other potential factors that put certain women at higher risk for growing fibroids. Through prevention, Baird and others are hoping to make a dent in the more than $6 billion spent on this understudied women’s health condition each year.
Said Baird: “I think down the road, this is what can happen, and there can be much less surgical treatment and many fewer hysterectomies.”