Laparoscopic evaluation of the onset and progression of endometriosis

Objective: To clarify the pathogenesis of endometriosis on the basis of analysis of primary lesion sites, age at onset, rate of progression, and response to drug treatment. Study Design: The clinical records of 690 women with laparoscopically confirmed endometriosis were retrospectively analyzed based on the revised American Fertility Society point system. Results: The primary site of endometriosis was the uterosacral ligament and pelvic peritoneum/pouch of Douglas in 73% of patients with stage I disease, whereas only 16% had ovarian lesions. However, disease progression was associated with an increasing frequency of ovarian lesions. In terms of the revised American Fertility Society score, endometriosis progressed at a mean rate of 0.3 point per month. Thus the earliest onset of endometriosis was estimated at 3 to 4 years after menarche. Drug therapy improved the revised American Fertility Society score by about 50%. Patients with a low response to an initial cycle of therapy generally showed further improvement after an additional treatment cycle. Conclusions: Because endometriosis may occur as early as 3 to 4 years after menarche and gradually progresses, drug therapy, including long-term treatment, should be carried out in women with definitive evidence of endometriosis who must maintain their reproductive potential.