Risk factors for postoperative recurrence of deep infiltrating endometriosis during a 6- to 12-year follow-up

This study aimed to identify risk and protective factors for postoperative recurrence of deep infiltrating endometriosis (DIE). We analyzed 320 patients undergoing laparoscopic excision with ≥ 6 years follow-up at the First Affiliated Hospital of Sun Yat-sen University. Cumulative recurrence rates increased from 7.1% at 6 years to 14.1% by 12 years post-surgery. Multivariate analysis identified left ovarian endometrioma (EMA) as an independent risk factor (HR: 6.413, 95% CI: 2.961-13.889, P < 0.001), while older age (HR: 0.836, 95% CI: 0.788-0.887, P < 0.001), GnRH-a use ≥ 6 months (HR: 0.324, 95% CI: 0.178-0.589, p < 0.001), and postoperative pregnancy (HR: 0.847, 95% CI: 0.179-0.748, p = 0.006) were protective. Gravidity, parity, and unilateral EMA showed univariate associations (P < 0.05), but BMI, dysmenorrhea severity, infertility, and hysterectomy status were nonsignificant. These findings highlight left-side EMA presence was an independent risk factor for the recurrence of deep infiltrating endometriosis after surgery during long-term follow-up. Age, use of GnRH-a for 6 months and postoperative pregnancy were protective factors against recurrence.