Is endometriosis a disease?

Recent comparative studies and developments in our understanding of the pathogenesis and pathophysiology of endometriosis have led to increasing doubts about whether it should always be considered a disease. Widespread use of laparoscopy for gynaecological investigation and treatment, recognition of non-pigmented lesions which are more active than classical implants, and the documentation of microscopic lesions in visually normal peritoneum, have all resulted in an increase in the frequency with which endometriosis is diagnosed. Recent studies suggest a prevalence of up to 80% in women complaining of infertility or pelvic pain, but also in up to 22% of fertile asymptomatic women undergoing sterilization. Perhaps it is a normal physiological variant, being present in such a high proportion of the population. Circumstantial evidence suggests this may be so, and the results with placebo treatment in controlled trials suggest that endometriosis is self-limiting and will regress or disappear spontaneously in 58% of women. The frequency and severity of symptoms which are often presumed to result from endometriosis do not correlate with the extent or site of lesions. Most women are pain-free. There is no dysmenorrhoea in up to 77%, no dyspareunia in up to 70%, and no pelvic pain at all in up to 61% of women with endometriosis. The pathophysiology of pain related to endometriosis is not understood. There is no medical or conservative surgical treatment that is wholly effective for symptom relief, and there is considerable placebo benefit. All treatments have risks or side-effects, and recurrent symptoms will develop in up to 45% of women within 5 years. For these reasons treatment should only be used where endometriosis fulfils the criteria of a disease, showing signs of progression with tissue damage or physiological disturbance. Asymptomatic endometriosis without tissue damage should not be considered a disease and should not be treated. Treatment of pain associated with minor endometriosis, or prophylactic treatment to prevent progression, must be regarded as empirical and not the specific requirement to control what is a questionable disease.