In a systematic review published in 2004 to determine the effectiveness of systemic medical therapies used for hormonal suppression before or after surgery for endometriosis, or before and after surgery for the eradication of endometriosis, improvement of symptoms, pregnancy rates, and overall tolerability, by comparing them with no treatment or placebo, 11 trials were included (324). Five trials compared postsurgical medical therapy with surgery alone (without medical therapy) and assessed the outcomes of pain recurrence, disease recurrence, and pregnancy rates (331–334). There was no statistically significant reduction in pain recurrence at 12 months (relative risk [RR] 0.76; 95% CI, 0.52–1.10), but the difference at 24 months approached statistical significance (RR 0.70; 95% CI, 0.47–1.03). There was no statistically significant difference between the use of these medical therapies after surgery compared to surgery alone with regard to disease recurrence (RR 1.02; 95% CI, 0.27–3.84) or pregnancy rates (RR 0.78; 95% CI, 0.50–1.22). Postsurgical medical therapy was compared to surgery plus placebo in three studies (332,335,336). There was no difference between medical therapy and placebo with regard to the measures for pain; multidimensional pain score (WMD −0.40; 95% CI, −2.15–1.35); linear scale score (0.10; 95% CI, −2.24–2.44); or change in pain (−0.40; 95% CI, −1.48–0.68). There was no difference between medical therapy and placebo for pregnancy rates (RR 1.05; 95% CI, 0.44–2.51) or total AFS scores (WMD −2.10; 95% CI, −4.56–0.36). There was no significant difference between presurgery hormonal suppression and postsurgery hormonal suppression for the outcome of pain in one trial (323).
These results were confirmed in another randomized controlled trial with 5 years of follow-up, showing that GnRH analogue treatment with triptorelin depot 3.75 intramuscular after operative laparoscopy for stages III and IV endometriosis was comparable to placebo injections with respect to time to relapse of endometrioma, pain recurrence, and time to pregnancy (337).
There is circumstantial evidence that regular postoperative use of OCs effectively prevents endometrioma recurrence (338). In a prospective controlled cohort study with a median follow-up of 28 months after laparoscopic excision of ovarian endometriomata, the 36-month cumulative proportion of subjects free from endometrioma recurrence was 94% in women who always used cyclic oral contraception compared with 51% in those who never used it (p <.001; adjusted incidence rate ratio [IRR[0.10; 95% CI, 0.04–0.24) (338).