Use of intraperitoneal interferon alpha-2b therapy after conservative surgery for endometriosis and postoperative medical treatment with depot gonadotropin-releasing hormone analog: a randomized clinical trial.

Objective: To evaluate the possible therapeutic effects of interferon alpha-2b left in the peritoneum after surgery, followed by or not followed by treatment with GnRH analogs.

Design: A prospective, randomized clinical trial.

Setting: University hospital.

Patient(s): Fifty-two infertile patients with moderate or severe endometriosis.

Intervention(s): Laparotomic conservative surgery and either interferon alpha-2b or saline alone left in the pouch of Douglas followed by administration of either GnRH analogs depot or oral indomethacin with transvaginal echography and analysis of CA-125, immunoglobulins, and lymphocyte populations.

Main Outcome Measure(s): Recurrence of endometriosis was considered clinically, echographically, and laparoscopically.

Result(s): Recurrence of endometriosis in four cases without interferon (15.4%) versus 11 patients (42.3%) with interferon alpha-2b. Life table analysis showed significant differences between the groups with and without interferon 21 months after conservative surgery. There were no differences in the recurrence between the groups with or without GnRH analogs. Likewise, there were no significant changes in immunoglobulins and lymphocyte populations among patients with and without recurrence of endometriosis. The patients that received GnRH analogs depot showed a decrease in the number of CD16 and an increase of CD11b cells after treatment.

Conclusion(s): The use of interferon alpha-2b within the peritoneal cavity after conservative surgery may be inappropriate because it increased later recurrence of endometriosis. The postoperative treatment with GnRH analogs did not significantly reduce the recurrence rate. Immunoglobulins and lymphocyte populations did not change in relation to the recurrence of endometriosis.