Fibroids (medically known as leiomyomas) are tumours developing in the muscle of the womb. They are the commonest tumours in women and they are generally benign. Some have found that they may be present in 50% of women. The exact cause of fibroids is unknown. They are more common in women of Afro-Caribbean origin. Fibroids tend to grow during reproductive years and to become smaller after the menopause indicating that the sex hormones (oestrogens and progestogen) must be implicated.
Some fibroids distort the cavity of the womb (submucosal
Figure 23.1) resulting in menstrual disturbance. Occasionally, these submucous fibroids can be squeezed out to appear at the cervix. Other fibroids migrate to the outer surface of the uterus (subserous) and may press on other pelvic structures such as the bladder. Small fibroids do not generally require treatment although it is probably wise to assess them at intervals to check that they are not growing.
Figure 23.1
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The majority of fibroids are small and cause no problems. Fibroids may be present in 50% of women so that the fact that they co-exist with a symptom such as pelvic pain does not necessarily prove cause and effect (Q4.3).
Heavy periods are often associated with fibroids. In one study, 30% of women presenting with heavy periods had fibroids seen on hysteroscopy (Q 24.8). There was, however, no difference in the incidence of fibroids in the group with heavy periods and another group who did not have heavy periods. Many women who present with heavy periods are found to have fibroids but proof that the fibroids are the cause of the problem is lacking. There have been very few studies to confirm that removing fibroids reduces heavy periods.
Bleeding between periods (intermenstrual bleeding IMB) can be related to a submucous fibroid (Figure 23.1).
Pelvic pain, like heavy periods, is a frequent problem and may co-exist with fibroids. They are not usually the cause of pain unless they are being squeezed out through the cervix or they are attached to the outer surface of the uterus and start twisting (torsion). If there is any doubt, it may be helpful to undertake a pelvic examination at the time that the pain is present. On occasion, a fibroid may lose part of its blood supply resulting in degeneration and acute pain. Degeneration of a fibroid is more common during pregnancy but can occur at other times.
Infertility and recurrent miscarriage investigation frequently demonstrate fibroids. It should not be assumed that the fibroids are the cause of the problem.
Submucosal fibroids had the strongest association with lower ongoing
pregnancy rates primarily through decreased implantation. Cumulative
pregnancy rates appear to be slightly lower in patients with intramural
fibroids. Patients with intramural fibroids also experience more
miscarriages, (20.4% vs 12.9%). Adverse obstetric outcomes are rare and may
reflect age or other differences in fibroid populations. Increased risk of
malpresentation (odds ratio, 2.9; 2.6-3.2), caesarean (odds ratio, 3.7;
3.5-3.9), and preterm delivery (odds ratio, 1.5; 1.3-1.7) have been
reported; however, the incidence of labor dystocia was low (7.5%). There is
no conclusive evidence that intramural or subserosal fibroids adversely
affect fecundity. More prospective, controlled trials are needed to assess
the effects of myomectomy. Good maternal and neonatal outcomes are expected
in pregnancies with uterine fibroids.0801
Bladder symptoms including increased frequency of bladder emptying may be due to large fibroids pressing on the bladder (Q 29.9)
Occasionally abdominal enlargement may be the presenting symptom of large fibroids.
The risk of malignant change of a fibroid is extremely small. The figure often quoted is one in a thousand but this is probably derived from examination of fibroids that have been removed and excludes the majority of fibroids that have not been removed. Rapid enlargement of a fibroid could indicate the possibility of malignant change.
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The diagnosis depends on the story, clinical findings and investigations. The doctor can usually feel the fibroids when examining the uterus. If they are on the side of the uterus they need to be distinguished from a tumour of the ovary. Ultrasound is helpful in confirming the nature of the swelling. When there is intermenstrual bleeding, hysteroscopy (Q 24. 8) is indicated to see if there is any abnormality within the uterine cavity such as a submucous fibroid or polyp.
How can fibroids be treated?
In general treatment is only required if the fibroids are causing symptoms. The fact that fibroids are found during routine examination does not generally mean that action is indicated although you may wish to have check ups for reassurance that the fibroids are not enlarging unduly. When there are small fibroids and heavy periods, medical treatment should still be considered before resorting to surgery.
If fibroids become particularly large they may require surgical removal. Gynaecologists generally assess the size of the uterus by comparing it to the size expected during a pregnancy. As an approximate guide, if the uterine size is larger than 18 weeks size, surgery is probably indicated. In younger women who wish to retain their fertility, the fibroids can be shelled out of the womb (myomectomy). If fertility is not a requisite, hysterectomy
(hysterectomy) is likely to be the preferred operation. It has been estimated that once in every hundred myomectomies uncontrollable bleeding occurs and in such circumstances hysterectomy becomes necessary as a life-saving procedure.
GnRH analogues (gonadotrophins) reduce oestrogen and progesterone levels and they are frequently used to reduce the size of the fibroids pre-operatively. On average, fibroids will be reduced by about a third of their size after three months and perhaps by a half after six months. GnRH analogues can be used by themselves for a maximum of six months as there is a risk of bone thinning (osteoporosis) and the oestrogen protection against arterial disease would also be lost (Q 26.23). If myomectomy is not performed the fibroids rapidly return to their pre-treatment size. There has been recent suggestion that GnRH analogues could be continued for more than six months provided oestrogen is replaced in the form of HRT (HRT-Add-Back); early studies indicate that the oestrogen replacement does not reduce the benefits of the GnRH on fibroid size. GnRH analogues are expensive, precluding long-term use unless there are exceptional circumstances. When fibroids are associated with heavy periods, GnRH analogues for a few months pre-operatively will provide two advantages: In addition to shrinking the size of the fibroids, they should stop the periods, allowing anaemia to be corrected thus reducing the likely requirement for blood transfusion.
Uterine artery embolisation is a new treatment for fibroids. The uterine arteries provide about 50% of the blood supply to the uterus. A fine catheter is introduced into an artery in the right groin. Poly Vinyl Alcohol particles are placed into the uterine arteries, under x-ray control, with the objective of starving the blood supply to the fibroids. The starved fibroids should then disappear or become smaller. After the procedure there may be pain and for three or four weeks there may be bleeding. Patients usually stay in hospital for a couple of days and may return to work after two weeks.
Data from the Royal Surrey County Hospital trial of 30 patients have achieved successful ongoing pregnancies with no obvious problems to date. Success rates of 85% are being achieved. A few patients stop seeing their periods. The main complication of fibroid embolisation is infection requiring hysterectomy in about 1% of cases.
Twenty patients have become pregnant following fibroid embolisation with no obvious problems to date. Deaths from fibroid embolisation (1:2500) are uncommon and appear to be less than for hysterectomy (1:1600). Fibroid embolisation is still undergoing trials to determine its benefits and risks.
The long-term results of uterine artery embolisation are awaited.
Minimal access surgery is an option in the treatment of fibroids. The laparoscopic route is applicable to sub-serous fibroids and hysteroscopy for sub-mucosal fibroids.
MRI-guided focused ultrasound treatment of uterine fibroids is a further new minimally invasive technique. Research into its place and value is being assessed.
Uterine Artery Embolisation is associated with less
complications than hysterectomy. About 1 in 4 women having UAE
require further treatment. Both treatments are safe and
effective over the medium term. The choice of treatment is a
matter of personal preference.0703
UAE is cheaper than hysterectomy even allowing for repeat
procedures. UAE is cost effective for those women who prefer
uterine conservation.0704
Temporary uterine artery occlusion for treatment of menorrhagia
and uterine fibroids using an incisionless Doppler-guided
transvaginal clamp provides a relatively simple means to treat
fibroids. This technique is under development.0604
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