Endometrial Polyps

Introduction

Endometrial  polyps are a localised overgrowth of glands and connective tissue around a  vascular core, or a small blood vessel.   Single or multiple polyps may occur ranging from a few millimetres to  many centimetres in size.  They may lie  flat against the surrounding endometrium or be very long and protuberant.

What  causes polyps?

Endometrial polyps are  common. Many cause no symptoms.  Their  prevalence is between 7.8 and 35% depending on the type of patient  studied.  Risk factors for the  development of polyps include advancing  age, high blood pressure, obesity and use of tamoxifen (a medication used  after treatment of breast cancer). The incidence is greatest in women between  40 and 50 years of age.  The prevalence  appears to increase with age during the reproductive years, and also appears to  be higher in infertile women.  This suggests  a causative relationship. Women using tamoxifen have a 30-60%  risk of developing polyps. It is uncertain  whether hormone replacement therapy increases the incidence of polyps. Use of progesterone-only contraception such  as Implanon, Mirena or Depo Provera as well as use of the combined oral  contraceptive pill may reduce the risk of polyps.

Both  an abnormal overgrowth of endometrial cells and endometrial cancer may  originate in endometrial polyps.  Malignancy may occur in up to 13% of endometrial polyps. The risk of malignancy increases  with age but the risk in premenopausal women appears to be low.  Risk  factors for endometrial cancer within a polyp include abnormal bleeding and  increasing polyp size.  Other general  risk factors for endometrial cancer such as obesity,  diabetes and hypertension and long standing irregular periods also increase  the risk as does use of tamoxifen.

What  are the symptoms of an endometrial polyp?

• Bleeding between cycles
• Heavy periods
• Fertility problems
• Problems associated with polyp to cancer progression
• Large polyps may protrude through the cervix causing bleeding after intercourse

Diagnosis  of Endometrial Polyps

The best  test, against which others are compared, for diagnosing endometrial polyps is hysteroscopy  and curettage under general anaesthetic.  This enables direct visualization of the  polyp.  Most patients come to my office having  had bleeding problems and a trans-vaginal ultrasound (TVUS).  TVUS has up to 96% chance of detecting  endometrial polyps compared to hysteroscopy and curettage. The addition of  colour flow or power Doppler to the ultrasound examination may improve the  chances of detecting a polyp.  Saline-infused  sonography (SIS) can also increase the chances of detecting a polyp and  is probably the best was of doing this using ultrasound.

Hysterosalpinography  (HSG- an x-ray performed after pushing dye  through the cervix into the endometrial cavity) also has a high chance of  detecting endometrial polyps but is more invasive and more painful than  ultrasound.  It also involves using  ionizing radiation and frequently iodine containing contrast.  Other imaging methods such as MRI are useful  but expensive, and CT scanning has a limited role because of its low  sensitivity.

Can ultrasounds determine malignant from non-malignant polyps?

Unfortunately ultrasound is unable to  distinguish malignant from non-malignant polyps, so  we can’t use this as a means of deciding who needs a curette and who does not.

Management of endometrial polyps

Around  25% of endometrial polyps spontaneously disappear over the course of one  year.  Smaller polyps are most likely to  regress (<10mm) especially if they don’t have a central feeding blood  vessel.  Small polyps are found  incidentally in post-menopausal women unlikely to be malignant (insert  reference) and observation may be an option after appropriate discussion.

Medical management of endometrial polyps

Medical  management (taking tablets) has a very limited role in treating endometrial  polyps.  Some kinds of hormonal therapies  may have a preventative role for polyp formation, such as use of the releasing intrauterine device (Mirena),  however its specific use for the treatment or prevention of polyps is the  subject of research.

Surgical  management

Investigation  and removal of polyps is generally carried out under general anaesthetic.  A blind dilatation and curettage (that is,  performing a curette without first looking into the uterus with a hysteroscope)  has been reported to remove endometrial polyps in only 8% of cases whereas the  addition of polyp forceps (similar to long tweezers) may increase complete  removal to around 41%.  The  recommended way of removal is hysteroscopic resection. Hysteroscopic  polypectomy is effective and safe and reduces the recurrence rate compared with  removal by polyp forceps.

Effects  of surgical treatment

The  removal of endometrial polyps usually  does not result in a decrease in menstrual flow although bleeding between  periods may be greatly improved.   Intrauterine adhesions (Asherman’s syndrome) are rare after polypectomy  because the myometrium (muscle of the uterus) is not included in the curette or  resection.

Occasionally  when hysteroscopic removal of a polyp cannot be carried out, hysterectomy may  be recommended in symptomatic women who have risk factors in malignancy.  However this is rare.

Polypectomy  in infertile women is very effective in improving fertility with fertility  rates improving to 40-80% over the ensuing 12 month, i.e.: almost as good as  the baseline pregnancy rate over 12 months of 84%.

Spontaneous  pregnancy rates as well as IVF pregnancy rates are increased.

Summary

• Polyps are localized overgrowths of the endometrium and may be either benign or       malignant (cancer)
• Medical management of polyps is not recommended
• Hysteroscopic resection of polyps remains the best treatment
• Removing polyps may not decrease menstrual flow but usually improves bleeding       between periods
• Removing endometrial polyps in the context of infertility will greatly improve       pregnancy rates

Please read  these notes in conjunction with procedure information sheet “Operative  Hysteroscopy” .