Surgical removal of superficial peritoneal endometriosis for managing women with chronic pelvic pain: Time for a rethink?

Abstract

Endometriosis is a potentially life-altering, estrogen-dependent condition which is associated with chronic pelvic pain. It affects an estimated 176 million women worldwide, making it as common as diabetes mellitus (DM).1 The socio-economic burden of endometriosis in the UK is in excess of £8.2 billion per year, with average worldwide costs amounting to around £8,500 per woman per year (similar again to DM).2 Evidence suggests that women with endometriosis are at higher risk of infertility, ovarian and breast cancer, melanoma, asthma, and some autoimmune, cardiovascular, and atopic diseases.3 A diagnosis of endometriosis should be considered when a woman presents with chronic pelvic pain and, as there are no accurate noninvasive biomarkers of endometriosis, the diagnosis generally necessitates a laparoscopy.1, 4, 5 Endometriosis is defined by the presence of endometrial-like tissue ('lesions') outside the uterus. Three subtypes of endometriosis have been described: superficial peritoneal, ovarian (endometrioma or 'chocolate cysts'), and deep.1 Superficial peritoneal endometriosis (SPE) is the most common and accounts for ~80% of all endometriosis. However, SPE is by no means a homogeneous condition—phenotypically its location and its extent varies, and it can co-exist with the other subtypes, as well as with adenomyosis. In addition, despite pain being the cardinal symptom of endometriosis, the underlying biological mechanisms of endometriosis-associated pain are not known for any subtype. The natural history of the disease is uncertain, e.g. it is not known whether SPE can progress to become another subtype, regress spontaneously, or whether disease progression (or lack of treatment) can lead to problems with infertility. Furthermore, there is poor correlation between pain severity and the amount, location, and subtype of the endometriotic lesions.1 The management options in national and international endometriosis guidelines for women with all endometriosis subtypes and condition-associated symptoms include surgical removal of lesions and medical treatment with ovarian suppressive drugs.1, 4, 5 The guidelines suggest that clinicians consider a 'see and treat' approach when SPE is identified at a diagnostic laparoscopy.4, 5 Surgical removal' requires appropriate surgical expertise and involves laparoscopic excision and/or ablation of the endometriotic lesions. Complete surgical removal is dependent on accurate recognition of the condition, including its extent and distribution, in addition to having the requisite skills safely and proficiently to excise or ablate the disease. These are skills that may be beyond those not specifically trained in this area, and there is perhaps an argument for diagnostic laparoscopy for pelvic pain to be undertaken only by those who are trained. The evidence behind these national and international endometriosis guideline recommendations are largely summarised in a meta-analysis of available data that concludes that laparoscopic treatment improves condition-associated pain (cited as 'better' or 'improved') compared with diagnostic laparoscopy alone at 6 months (odds ratio [OR] 6.58, 95% CI 3.31–13.10)'.6 However, this statement is based on data from just three randomised controlled trials (RCT), a total of only 171 participants with all three different subtypes of endometriosis, the use of multiple treatment modalities to remove the lesions, and data of 'moderate quality' when scored using GRADE (a recognised systematic and explicit approach to making judgements about the quality of evidence and strength of recommendations). Furthermore, only one RCT included in the analysis (with only 69 participants) has follow-up data to 12 months showing benefit of surgery (OR 10.00, 95% CI 3.21–31.17). Using GRADE, this represents 'low quality evidence'. Thus, there is little evidence to demonstrate whether surgical removal of isolated SPE at diagnostic laparoscopy improves overall symptoms and quality of life. Indeed, it has been proposed that SPE may not be responsible for pain, and that it may be due to other overlooked causes (e.g. irritable bowel syndrome, bladder pain syndrome, musculoskeletal disorders, somatic symptom disorder). Treatment for these other conditions may be delayed by concomitant surgical treatment at the time of diagnostic laparoscopy because recovery may be prolonged and due to subsequent time lapses while symptomatic outcomes are evaluated.7 Consequently, the UK National Institute of Clinical Excellence (NICE) Endometriosis Guideline recommends further research into the effectiveness of laparoscopic treatment of SPE to manage endometriosis-associated pain.5 This research recommendation is supported by the outcome of the James Lind Alliance Priority Setting Partnership Initiative for Endometriosis, established to identify the key research questions prioritised by both women with endometriosis and the healthcare practitioners involved in their care.8 We also belie