Uterine fibroids, leiomyomas or myomas are common benign smooth muscle tumours occurring in up to 70-80% of women by the age of 50. These tumours have a fibrous texture due to high collagen and extracellular matrix content along with myometrial cells – hence the name “fibroids”. They occur during the reproductive years and diminish in the postmenopausal years. They grow under oestrogen and progesterone stimulation but other factors such as the insulin–like growth factors (IGF-II particularly) and factors involving the retinoic acid pathway are also important. (See Table 1)

Types of fibroids

Intramural: the most common and contained within the myometrium.

Submucosal: distort the endometrial cavity and are sometimes completely contained within the cavity (intracavity).

These may cause severe flooding and menstrual pain.

Subserosal: grow from the outer surface of the uterus and distort its shape and size. Some are pedunculated and may undergo torsion.

They are often asymptomatic but may cause pressure symptoms on the bladder and/or bowel.

Clinical presentation

Most fibroids are asymptomatic but symptoms may occur due to the site, size and number.

Abnormal uterine bleeding

• Increased menstrual heaviness +/- flooding
• Prolonged bleeding
• Intermenstrual bleeding
• With or without pelvic pain, including
• dyspareunia
• Associated iron deficiency or anaemia

Pressure symptoms

Due to the position and size of the uterus there can be heaviness or pressure in the back, bowel and bladder. This may cause the following:

• Urinary retention
• Incomplete emptying of the bladder
• Urinary frequency
• Incomplete emptying of the bowel
• Large palpable abdominal mass with increasing girth
• Backache or pain

Infertility

It is still not clear whether fibroids cause infertility. From mostly retrospective studies in IVF patients with fibroids, the presence of a submucosal or an intramural fibroid adjacent to the cavity may be associated with lower implantation rates and therefore pregnancy.

Pregnancy

The presence of fibroids may have the following implications for pregnancy:

• Increased risk of miscarriage in the second trimester
• Increased risk of preterm labour and delivery
• Increased infection
• Increased postpartum infection
• Increased operative delivery due to obstruction of the birth canal.

Investigations

• Palpation of an enlarged and/or irregular shaped uterus.
• If abnormal uterine bleeding is the main symptom the following should be considered:
  - FBE
  - TFTs
  - Iron studies.
• Ultrasound: transvaginal ultrasound.
• Saline infusion sonography will outline a submucosal fibroid.
• Hysteroscopy +/- endometrial biopsy or curettage will exclude submucosalfibroids.

Management

In most cases where asymptomatic fibroids are incidentally diagnosed, no treatment is necessary.

Medical therapies

• Medications to reduce blood flow such as tranexamic acid, progestins or oral contraceptives may be used. However, hormonal therapies may increase the size of fibroids.
• Progestin-releasing intrauterine system (IUS) will reduce blood flow unless the uterine cavity is markedly distorted.
• Gonadotrophin-releasing hormone (GnRH) agonists are sometimes prescribed before surgery or pregnancy to reduce the size of the fibroids. However, fibroids will recommence growing after cessation of therapy which maybe for up to six months. GnRH agonists induce a temporary hypo-oestrogenic state causing menopausal symptoms and bone loss if used for more than six months.

Interventional therapies

Uterine artery embolisation

The side-effects include ischaemic abdominal pain and, in approximately 25%, a fever. Complications may include groin haematoma, prolonged vaginal discharge, expulsion vaginally of the fibroid, either temporary or permanent ovarian failure and infertility or subfertility. After three years up to 20% may require a further procedure. It can be used in women who wish to become pregnant.

MRI-guided ultrasound

A relatively new procedure which uses high intensity focussed ultrasound waves to cause a local increase in temperature in the fibroid tissue, resulting in coagulation necrosis while sparing the surrounding normal structures. It is currently not recommended for women who wish to become pregnant.

Surgery

Surgery is still the gold standard for treatment of symptomatic fibroids. The size, site and number of fibroids need to be carefully evaluated before surgery.

Myomectomy is performed when a woman wishes to retain her uterus or retain her fertility.

Hysterectomy is recommended when the uterus is large, with multiple fibroids causing major symptoms when a woman does not wish to retain her fertility.

New techniques

• Myolysis destroys fibroid tissue either by heat, cold coagulation or laser. It can be performed, as described using MRIguided ultrasound, but also hysteroscopically and laparoscopically.
• Laparoscopic uterine artery embolisation and temporary uterine artery occlusion are in development.
• Medical therapies such as the selective oestrogen receptor modulators (SERMS) and aromatase inhibitors are being trialled. Mifepristone (RU486) has shown reduction in fibroid and uterine volume.

 Facts on fibroids - 5 February, 2010 286.33 Kb   

References

Hehenkamp WJK, Volkers NA, Birnie E, Reekers JA, Ankum WM.

Symptomatic Uterine Fibroids: Treatment with Uterine Artery Embolization or

Hysterectomy—Results from the Randomized Clinical Embolisation versus Hysterectomy (EMMY) Trial Radiology March 2008 246:823-832;

Van Voorhis B. A 41-Year-Old Woman With Menorrhagia, Anemia, and Fibroids Review of Treatment of Uterine Fibroids JAMA. 2009;301(1):82-93

See also Medical Observer http://www.medicalobserver.com.au/

Content Updated Febraury 5, 2010