Endometriosis: Q&A with Associate Professor Tan Hak Koon and Dr Andy Tan

Roshini Claire Anthony
27 Mar 2017
Endometriosis: Q&A with Associate Professor Tan Hak Koon and Dr Andy Tan

Associate Professor Tan Hak Koon, Head and Senior Consultant, and Dr Andy Tan, Associate Consultant from the Department of Obstetrics & Gynaecology at Singapore General Hospital (SGH) speak to Roshini Claire Anthony about the causes of endometriosis and the importance of early diagnosis and treatment.


What is the prevalence of endometriosis in Singapore and how does it compare to the global prevalence?

The exact prevalence of endometriosis remains unknown. Globally, it is estimated that 10 percent of women are affected by this condition. In Singapore, it is believed that the prevalence is higher. The possible reason for this may be lower consumption of combined oral contraceptive pills (COCP) by our population. COCP use does provide prophylaxis against either the development or recurrence of endometriosis. Manipulation of the endogenous hormonal milieu forms the basis for the medical management of endometriosis.

What are the causes of endometriosis?

Endometriosis is defined as the presence of endometrial-like tissue outside the uterus. It most commonly involves the pelvis, particularly the ovaries, uterosacral ligaments, cul-de-sac, and rectum. This results in chronic inflammatory reactions leading to adhesions, pelvic pain, and subfertility. The pathogenesis remains elusive, but the most accepted theory is retrograde menstruation. Other possible causes that have been described are progesterone resistance, oestrogen imbalance, and aberrant immunological response.

What are the risk factors for endometriosis?

The most significant risk factor is family history (having a member of the family affected by endometriosis). Other risk factors include early menarche, late menopause, short menstrual cycles, being nulliparous, and a low body mass index.

Endometriosis affects women from all ethnic and social groups, predominantly during their reproductive years (25–35 years). Risk factors are important considerations as they do affect the age of onset of endometriosis; it can affect women from as early as in their 20s.

Are there any biomarkers, diagnostic tests, or cardinal signs of endometriosis?

Women with endometriosis typically present during their reproductive age with symptoms such as dysmenorrhoea (painful periods) and dyspareunia (pain during sexual intercourse), as well as chronic pelvic pain, ovulation pain, perimenstrual symptoms, fatigue, and infertility. The symptoms are likely to be more severe with a longer duration of illness. However, some women remain asymptomatic where endometriosis is incidentally diagnosed during surgery or imaging for other indications.

It is difficult to establish the diagnosis solely based on symptoms as there is considerable overlap with other conditions such as irritable bowel syndrome and pelvic inflammatory disease. Findings of pelvic tenderness, a fixed retroverted uterus, tender uterosacral ligaments, or enlarged ovaries during clinical examination are suggestive of endometriosis. The diagnosis becomes more certain when a transvaginal pelvic ultrasound shows endometrioma, uterosacral and/or rectal nodules. Although serum CA-125 levels may be elevated in endometriosis, routine measurement of serum CA-125 levels has no value as a diagnostic tool.

How common is misdiagnosis?

Thankfully, it is not common to misdiagnose endometriosis, as women with the condition usually present with severe dysmenorrhoea. With easily accessible ultrasound service and specialist referral, it is usually diagnosed early. It is only challenging in women with chronic pelvic pain and a normal pelvic ultrasound, where superficial or peritoneal endometriosis can be missed even during a laparoscopy as the disease is so subtle.

When endometriosis is misdiagnosed, the condition is likely to worsen progressively. These include worsening signs and symptoms as well as infertility. It is therefore important to consider endometriosis as a differential diagnosis when a woman presents with pelvic pain and appropriately refer them to a gynaecologist for further assessment, particularly when they are in their reproductive age. Delay in diagnosis will badly impact the patient’s quality of life.

What are the current treatment options available?

Depending on the severity of the disease, ideal practice is to diagnose and remove endometriosis surgically in the same setting. The most effective treatment for endometriosis is surgical excision (provided that adequate preoperative consent has been taken). The goal of surgery is to excise or coagulate all visible endometriotic lesions and to restore normal pelvic anatomy. However, in women who refuse surgical intervention, hormonal treatment such as COCPs, levonorgestrel intrauterine device (LNG IUS), progestogens, and gonadotropin-releasing hormone (GnRH) agonists can provide endometriosis-related pain relief.

What are the challenges faced in diagnosing/treating endometriosis?

The biggest challenge in treating endometriosis is when you have a patient in her early 40s who desires fertility while at the same time has debilitating pain due to severe endometriosis. Surgical excision will help to improve endometriosis-related pain; however, there is a risk of further reducing her ovarian reserve and her subsequent chance to conceive. In such circumstances, time is of the essence as age plays an important role in the quality of the oocytes. Sometimes, these women may need to resort to assisted fertility treatment.

What is the role of the primary care physician in ensuring timely diagnosis and treatment of endometriosis?

Primary care physicians play an important role as they are usually the first point of contact in the medical frontier to women presenting with nonspecific abdominal pain. Hence it is important for primary care physicians to be well-informed about the cardinal signs and symptoms suggestive of endometriosis so that appropriate timely referrals can be made.

Are there any misconceptions about endometriosis that should be dispelled?

The perception that endometriosis equates to infertility would be the main misconception that should be dispelled. Undeniably, the majority of women with pain and infertility have underlying endometriosis (35–50 percent), but not all of them are infertile. Furthermore, evidence has shown that operative laparoscopy increases spontaneous pregnancy rates in all stages of endometriosis. Therefore, women who fail to conceive within one year from unprotected intercourse should be referred to a specialist in a timely manner.

Associate Professor Tan Hak Koon

Dr Andy Tan

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