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Gynaecologists commonly have conversations with General Practitioners and other specialists about an ultrasound scan finding of uterine fibroids.

Women usually have scans for a reason, such as abdominal pain or abnormal uterine bleeding. On face value fibroids may seem an obvious and measurable abnormality to account for the patient’s problems, however in many cases they may be an ‘incidentaloma’.

As many as one in four women may have a uterine fibroid. They are even more common in woman of African ancestry1.

In many cases no treatment will be required, while in others they may be the cause of a number of symptoms. Management of fibroids must be individualised and treatment selective.

Risk factors for leiomyosarcoma include:

  • Advancing age (mean age diagnosis is 60 years old)
  • African American ancestry
  • Previous pelvic irradiation
  • Tamoxifen exposure
  • Hereditary leiomyomatosis renal cell cancer syndrome
  • Childhood retinoblastoma.

Who does require treatment?

No practitioner wants to ‘miss the sinister mass’. Fibroids (like any cell) can become malignant. Fibroids are clonal expansions of the smooth muscle of the myometrium, and malignancies are therefore termed leiomyosarcomas.

The odds of malignant transformation are variably quoted between 1:350 – 1:2000. Importantly however, this is based on surgical specimens, so the true population incidence is likely to be very low. Overall we would consider this to be a relatively rare gynaecological malignancy, especially in women under the age of 40. Those requiring treatment can be put in to two groups: those at-risk, and those with symptoms.

So what are the risk factors for malignancy?

Fibroids are uncommon in adolescents and become more common in those approaching menopause, and of course that is often associated with irregular bleeding patterns.

Malignancy may be more common in larger fibroids or those with rapid interval growth2. If there are concerns (particularly relating to recent-onset pelvic symptoms, pressure effects, or scan findings of an enlarging mass) referral for specialist assessment is prudent. The finding of a new and enlarging fibroid in a postmenopausal woman is of particular concern.

The other group who will likely benefit from treatment are those with abnormal bleeding, pain or infertility. A clinician must be judicious however with attributing the cause of these presentations to fibroids – they may well be an ‘innocent bystander’.

Fibroids are generally described as being in three locations: subserosal (on the outside of the uterus), intramural (within the muscular wall), or submucosal (impinging on the endometrial cavity). Large subserosal and intramural fibroids may also impinge on the endometrial cavity. Fibroids identifiable in the endometrial cavity may cause heavy and / or prolonged menstrual bleeding. Intramural fibroids may also cause this, but subserosal fibroids generally will not3. Women with intermenstrual and postmenopausal bleeding should have an endometrial assessment.

All women with abnormal uterine bleeding should be considered for endometrial biopsy to investigate for malignancy, especially if it does not respond to simple treatment strategies.

Women with fibroids uncommonly present with pain. Fibroid degeneration is rare, but may be more common in pregnancy when supraphysiological estrogen levels may cause rapid growth. Frequently this will reverse somewhat postpartum, and the fibroid appearance may change, with evidence of cystic degeneration. Pain may also be caused by heavy bleeding (cramping pain with bleeding), or pressure effects on other organs. Torsion of a pedunculated fibroid is also quite uncommon but can cause intermittent severe pain. Pressure effects can include constipation, urinary frequency/nocturia (but not necessarily urgency) and rarely urinary obstruction. Women with heavy, prolonged periods, back pain, and dysmenorrhea may have adenomyosis; an adenomyoma may be confused with a fibroid.

Women with subfertility will commonly have a fibroid found on an ultrasound scan, however only a minority will require treatment, and routine removal will likely lead to increased morbidity and delay in necessary treatments. Submucosal fibroids and those impacting on the endometrial cavity appear to be associated with reduced fertility and an increase in miscarriage rates. Large fibroids may cause problems with ovum (egg) capture, tubal transport and sperm migration. The decision to treat should be based on an absence of other causes of subfertility, other symptoms, and the progress of fertility treatment undertaken thus far4. Surgical management may also have impacts on fertility (due to adhesion formation) or obstetric outcomes such as necessity for caesarean section, or rarely uterine rupture in pregnancy.

It is clear that a careful assessment is necessary to determine in which patients symptoms are attributable to the fibroid(s), and in which the fibroids just happen to be there! What treatments are available? Medical treatments are generally poorly effective and only useful in a few selected circumstances. If heavy bleeding is effectively treated by simple measures such as the combined oral contraceptive, cyclical Provera, or a Mirena, it is unlikely the underlying cause of the bleeding is solely the fibroids. Medications (including tranexamic acid) may well be useful to reduce bleeding, however. GnRH analogues such as Lucrin may be recommended to reduce the size of a fibroid in the lead up to surgery; there is evidence this may reduce blood loss. However, due to side effects and issues with bone demineralisation these are not a long-term strategy.

New agents such as Ulipristal, a selective progesterone receptor modulator, have shown promise in overseas trials; whether they become available here remains to be seen.

Treatment is generally surgical. Submucosal fibroids can be removed piecemeal through the cervix with a hysteroscope. Intramural and subserosal fibroids can be removed abdominally both as an open and closed (laparoscopy) procedure. A laparoscopic approach requires advanced training, and the fibroid will require morcellation for removal through small laparoscopic incisions. Morcellation has been the subject of controversy due to a perception of increased risk of dissemination of undiagnosed malignancy, or seeding of fibroid fragments through the abdomen. Recent approaches have focused on the use of a bag to contain the specimen while it is made small enough for removal through a minimal-access incision.

For women not wishing to retain childbearing a hysterectomy may be the most appropriate course of action. Even very large fibroid uteri can be removed laparoscopically. The surgery itself is longer and more difficult, but patient recovery is substantially improved.

  • Fibroids are the most common benign tumour of reproductive age women.
  • A large number of women with fibroids will be asymptomatic, and no treatment is required. Treatment carries risk.
  • A prudent gynaecologist will judiciously operate, and leave small asymptomatic fibroids alone.
  • When surgery is considered a minimally invasive option is preferred, but for safety an open procedure may be necessary.
  • In many women a hysterectomy may be first-line treatment.

References

  1. Baird D, Dunson D, Hill M et al. High cumulative incidence of uterine leiomyoma in black and white women: ultrasound evidence. AJOG 2003; 188(1): 100
  2. 2. Norris H, Taylor H. Mesenchymal tumorus of the uterus. Cancer 1966; 19(6): 755-66
  3. Practice bulletin no 128: diagnosis of abnormal uterine bleeding in reproductive-aged women. Committee on Practice Bulletins – Gynecology. Obstet Gynecol 2012; 120(1): 197
  4. Kroon B, Johnson N, Chapman et al. Fibroids in infertility – consensus statement from ACCEPT (Australasian CREI Consensus Expert Panel on Trial evidence). ANZJOG 2011; 51(4): 289-95.

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