Clinical Fibroid Issues
The prevalence of fibroids is high. In 1990, Cramer and Patel exhaustively examined 100 consecutive hysterectomy specimens at 2-mm slice thickness. Fibroid prevalence was 77%. In an US study, 1384 women between the ages of 35 and 49 were randomly selected for study in an urban health plan. Estimated cumulative incidence by age 50 was 70% for white women and >80% for black. The incidence of fibroids was measured in the study of 95,061 premenopausal nurses age 25 to 44. Incidence rate for white woman was 8.9 per 1000 and for blacks, 30.6.
Fortunately, most fibroids are small and never symptomatic. As stated by Cramer, fibroids are clinically much less common than their prevalence would predict, “Their clinically detectability reflects their size and number and not just their presence.”. There are approximately 107 million U.S. women over the age of 15. Although poorly documented, it is commonly stated that between 20%–50% of these adult women are clinically symptomatic from fibroids. If these estimates are even remotely correct, there are between 21 (107 × 0.2) and 53 (107 × 0.5) million American women with clinically symptomatic fibroids.
The frequency at which fibroids are observed in the uterus decreases with parity, cigarette smoking, birth control pill usage, and menopause, and increases with obesity. It has been widely presumed that parity, birth control pill usage, menopause, and obesity all influence fibroid prevalence through their influence on circulating estrogen levels. This may not be the case for any of these variables. It is defi nitely not the case for parity. Giving birth involves a period of uterine hemostasis that is associated with clot formation within the uterus. As we shall see, birth kills fibroids.
The burden of fibroid disease is not racially equal. Fibroids are more frequent in black women than white. Furthermore, fibroids in black women appear earlier, are larger, and produce symptoms longer in black women prior to definitive therapy than in white women. In a study of 335 women age 25 to 40, nonrandomly selected, fibroid prevalence was 5.4%. This figure is so out of line with other published data that many specialists simply reject it out of hand.
For approximately 200,000 American women, fibroid symptoms are sufficiently morbid to undergo hysterectomy annually. Approximately 118,000 American women undergo myomectomy for symptomatic fibroids. Medical hormonal therapies are extensively used to treat the symptoms of fibroids. Of the approximately one million American women treated annually with hormones for abnormal uterine bleeding symptoms, it is estimated that 250,000 have menorrhagia associated with fibroids. Although fibroids are very common and cause considerable morbidity, very little evidence-based research on treatment and management exists.
Societal and Patient Costs of Fibroids
Excluding morbidity costs or loss of income from time away from work for hysterectomy and myomectomy, it is estimated that direct hospital charges, outpatient attendances, and medical consultations cost $3 billion annually in the United States. Furthermore, women with fibroids that cause menorrhagia are often anemic. Finally, because of worry about failure of sanitary napkin protection during each menstrual period, women with menorrhagia prefer to stay home and, as a consequence, miss work. As stated by Vollenhoven, “These women will often be housebound on their heaviest days of menstruation, preferring loss of income to social embarrassment.” Fibroids are a large national expense.
Symptoms Associated with Fibroids
a. Bulk Symptoms
Fibroids are associated with 2 major groups of symptoms: menstrual abnormalities, primarily menorrhagia, fibroid pain and pelvic pain and discomfort. Pelvic pain and discomfort are readily explained by mass effect. As the fibroid uterus enlarges, the pelvis has too little space to accommodate its organs and an enlarging fibroid uterus. When the fibroid uterus presses on the bladder, urinary urgency and frequency occur. When the rectum is pushed and displaced, symptoms are referable to the bowels. These symptoms are referred to as bulk symptoms. Much of the discomfort of later pregnancy stems from the bulk of the uterus. Understanding bulk symptoms is relatively straightforward.
i. Uterine Volume
The 2 systems of measurement used to measure the size of the pregnant uterus are also used to measure the size of the fibroid uterus. In general, both systems are suitable for the measurement of uterine enlargement caused by fibroids. Occasionally, the uterus is enlarged in a manner that does not look like a chicken egg, and the ellipsoid measurement system is less accurate.
ii. Fibroid Volume
Unlike overall uterine volume, the volume of virtually all individual fibroids is suited to the prolate ellipsoid systems of measurement, because most fibroids are spherical or ellipsoid in shape.
Because menorrhagia without fibroids is a very common complaint and because fibroids are very common tumors, the coexistence of fibroids and menorrhagia is expected to be high without the relationship being causal. As Sehgal and Haskins stated, “Uterine bleeding in the presence of uterine fibromyomas is not necessarily the result of the fibromyomas.”
i. Some Evidence Suggests That Fibroids Cause Menorrhagia
Very little objective information is known about menstrual blood loss in women with fibroids. What is known is that women with fibroids cannot be compared to the menstrual blood loss distributions shown in figures 25 and 26. Women with fibroids were not members of the populations from which these 2 graphs were constructed. Consequently, the cutoff of 80 ml/menses separating menorrhagia from normal menses may or may not be applicable to women with fibroids. What little we do know about menstruation in women with fibroids indicates that they are quite different from healthy women selected for these population studies. Rybo studied menstrual blood loss with the alkaline hematin method in 215 women with blood loss greater than 80 ml/menses. When he separated these women into 2 groups by menstrual blood loss, women with fibroids were more frequently observed (figure 61). This suggests, but does not prove, that fibroids are causally related to menorrhagia.
Sulaiman et al. studied 50 women with fibroids who were on a waiting list to undergo uterine artery embolization. The presence of fibroids was confi rmed by MR imaging. Menstrual blood loss was measured by the alkaline hematin method. It can be seen in figure 62 that symptomatic women with fibroids define a menstrual blood loss curve very different from the curve defined by healthy women (figures 25 and 26). Women with fibroids have a large peak at menstrual blood loss of >200ml/menses. The normal population does not.
Women with fibroids have a different menstrual experience than women without fibroids. This difference may or may not be associated with menorrhagia. Wegienka et al. randomly selected a sample of 910 women aged 35 to 39 in the Washington, DC, area and obtained menstrual histories from them. Over the telephone, women were asked about gushing type bleeding, long menses, and high sanitary pad or tampon count. It should be noted that none of these measures has been demonstrated to be accurate surrogate for menorrhagia. They are simply descriptions of a woman’s menstrual experience. The subject responses were correlated with the presence or absence of fibroids as defined by US examinations. Of the women in the study, 57% did not know if they had fibroids or not at the time of the telephone interview; 46% of women with fibroids reported “gushing” during their menstrual periods as compared with only 28% without fibroids. In the women with fibroids, the frequency of reporting “gushing” increased from 40% in women who had fibroids less than 2 cm in diameter, to 60% for fibroids in the 2–5 cm in diameter range, to 90% for fibroids greater than 5 cm in diameter. Reported use of 8 or more pads or tampons on the heaviest days of menstrual bleeding also increased with fibroid size.
Women with fibroids who are not actively seeking medical care clearly have a different menstrual experience than women without fibroids. Women with fibroids in the Rybo and Wegienka studies above were not seeking medical treatment. In each study, women with fibroids were coping with excessive menstrual blood loss. In a study of women seeking medical help for menorrhagia, Fraser et al. measured menstrual blood loss with a modified alkaline hematin method. They observed increased menstrual blood loss in women with fibroids and symptoms of menorrhagia. What is a “normal,” tolerable volume of menstrual blood loss to a woman with fibroids has never been defined in the world’s medical literature. From what we do know, it is not ≤ 80 ml/menses.