Assessment of Fibroids
Fibroids (uterine leiomyomas) are the commonest non-cancerous lumps found in the uterus.
What are fibroids?
Fibroids (uterine leiomyomas) are the commonest non-cancerous lumps found in the uterus. They are made up of muscular and fibrous tissue and occur in 15 – 25% of all women in the reproductive (after puberty) age group. Fibroids do not occur in girls prior to puberty and shrink after the menopause. Fibroids are classified according to their position within the uterus.
Intramural myomas are located within the wall of the uterus.
Submucosal myomas occur just under the lining layer of the uterus and protrude into the uterine cavity. They extend into the cavity to a variable extent and usually the larger they become, the more they will protrude into the cavity. These fibroids are commonly a cause of abnormal uterine bleeding. They may also interfere with implantation of a pregnancy.
Subserosal myomas occur at the very outer layer of the uterus and may develop on a stalk – a pedunculated myoma.
Cervical myomas are located within the substance of the cervix.
What causes fibroids?
The exact cause of leiomyomas is unknown. There are a number of associations. We know fibroids grow under the action of hormones, in particular oestrogen. We know that they are less common in women who have had children. We also know fibroids are more common in women whose periods have started early in life, especially in those women whose periods have commenced before the age of 10.
We know that the use of the pill does not contribute to the growth of fibroids and is therefore not contraindicated in women who are known to have fibroids.
Symptoms associated with fibroids
Fibroids are often found as a co-incidental finding in women having an ultrasound for other reasons such as pregnancy or pelvic pain. In fact, the majority of myomas are small and are not associated with symptoms or problems. These fibroids are best left alone and if necessary, can be monitored by regular ultrasounds, unless symptoms arise. Fibroids can either be single or multiple and vary in size from a few millimetres to 10cm or more in diameter.
The symptoms associated with fibroids are divided into three groups:
- Heavy or prolonged periods
- Symptoms related to size of the fibroids, pressure symptoms such as pressure on the bladder resulting in urinary urgency or frequency, pressure on the bowel resulting in a feeling of incomplete emptying or constipation, general increase in girth and discomfort due to the size of the fibroids.
- Reproductive problems, this includes infertility issues and obstetric complications.
The commonest symptoms of fibroids relate to heavy and/or painful periods. It is important to remember that as fibroids are common it is possible to have abnormal bleeding not related to the actual fibroid. It is therefore, always important in women who have heavy or painful periods to exclude other causes, such as uterine malignancy.
In general menstrual disorders such as heavy bleeding are particularly associated with large and multiple fibroids and in particular, submucosal fibroids that enter the uterine cavity.
Often the pain associated with fibroids is due to the passage of clots associated with heavy menstrual flow.
Another possible complication of fibroids is degeneration. Degeneration occurs due to the fact that the fibroid outgrows its blood supply and the tissue making up the fibroid begins to die and become necrotic. This can result in quite acute pelvic pain and is typically seen in pregnancy. It does not interfere with the actual well-being of the fetus in the pregnancy but can be associated with significant pelvic pain.
A less common complication is torsion where a fibroid twists on its stalk.
Infertility or obstetric complications associated with fibroids
There is conflicting information as to whether submucous fibroid may reduce fertility. It may be due to advancing age in women with fibroids rather than the fibroids themselves. Certainly, submucous fibroids do increase the risk of miscarriage due to interference with implantation of the pregnancy. Fibroids can also interfere with the pregnancy by causing separation of the placenta from the uterine wall, or abnormal presentations of the baby such as a transverse lie, and an increase in the risk of premature delivery.
Diagnosis of fibroids
Firstly the actual history taken from a woman with fibroids may be highly suggestive of the diagnosis. The diagnosis is best made on a pelvic ultrasound following a routine pelvic examination. The fibroids are usually obvious on an ultrasound and both their position and size can be evaluated.
It is important in evaluating women with heavy and painful periods that a full blood count and iron levels are evaluated and other causes for heavy periods are also considered especially endometrial hyperplasia (an abnormal thickening of the lining of the uterus or endometrium) and uterine malignancy.
A very rare complication of uterine myomas is malignant change. The myomas are then called leiomyosarcomas. This diagnosis can be difficult but the best modality at assessing malignant change is an MRI procedure. This procedure however, still has limited accuracy. This is especially important in patients with significant symptoms, especially if the fibroids are growing rapidly. For this reason it is often appropriate to re-scan fibroids on a regular basis and especially reassess fibroids if new symptoms are developing.
When to treat fibroids?
As mentioned small asymptomatic fibroids can be left alone and there is no real indication for treatment unless symptoms develop or the fibroids grow rapidly.
The reasons for treatment are:
- Heavy or prolonged or painful periods.
- Pressure symptoms especially those involving the bowel or bladder.
- Reproductive dysfunction.
- Suspicion of malignant change.
As mentioned above it is important to not miss the diagnosis of a pre-cancerous or cancerous reason for heavy or painful periods. Fibroids are common and may not be the cause of your symptoms. For that reason appropriate investigation is always important in women who have significant symptoms.
The fundamental decision about treatment rests with the question “Does the patient wish to maintain her fertility?” If that is the case then more conservative treatment is indicated.
- A hysteroscopic resection of a submucous fibroid – fibroids that are largely within the uterine cavity can be approached through the cervix with an instrument called a resectoscope. This allows a heated wire to dissect out the fibroid and remove it. This is a day surgery procedure.
- Medical Therapy – the pill may significantly reduce the amount of bleeding and even pain, but will obviously not help pressure symptoms.
- A progesterone releasing IUD which releases continuous progesterone hormone has been shown to be particularly effective in fibroids as long as the fibroids are not submucosal or large.
- Tranxenamic acid – a non-hormonal oral medication that significantly reduces the amount of blood loss associated with periods. There are a number of studies showing a benefit in patients with fibroids.
- Another medical form of treatment involves gonadotropin-releasing hormone antagonists – there are a number of new medications which fundamentally suppress the menstrual cycle. These however, can be associated with significant side effects.
A group of drugs called GNRH agonists are often used pre-operatively to reduce the size of fibroids prior to surgery.
Uterine artery embolization – this procedure is performed as an invasive radiological procedure. A catheter is inserted in the groin in the femoral artery and fed up until the actual blood supply to the fibroid or fibroids are located. Tiny beads are then injected to obstruct the blood flow to the fibroid and reduce its nutritional support. This results in a reduction in size of the fibroids and is less useful in a woman with multiple fibroids.
Focused ultrasound surgery is another option. In this treatment high energy ultrasound waves are used to induce necrosis of the fibroids. A number of studies have shown that uterine artery embolization results in better long-term outcomes compared with focused ultrasound surgery.
Definitive surgery involves either a myomectomy where the fibroid alone is removed, or hysterectomy. Myomectomy is especially indicated in women who want to retain their reproductive potential. Myomectomy should only be performed if there is no suspicion of malignant change. Myomectomy can now be performed as a keyhole procedure which results in a shorter hospital stay and a more rapid recovery.
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