The lifetime risk of ovarian cancer is 1.9% among women with endometriosis compared with 1.3% among the general population. When an asymptomatic endometrioma is incidentally discovered on imaging, gynecologists must weigh the procedural complications and the potential for subsequent surgical menopause against future ovarian pathology or cancer.

We aimed to determine if performing unilateral salpingo-oophorectomy is a more cost-effective strategy for the prevention of death than surveillance for asymptomatic endometriomas.

We created a cost-effectiveness model using TreeAge Pro (TreeAge Software Inc; Williamstown, MA) with a lifetime horizon. Our hypothetical cohort included premenopausal patients with 2 ovaries who did not desire fertility. Those diagnosed with asymptomatic endometrioma underwent either unilateral salpingo-oophorectomy or surveillance (ultrasound 6–12 weeks after diagnosis, then annually). Our primary effectiveness outcome was mortality, including death from ovarian cancer or surgery and all-cause mortality related to surgical menopause (± hormone replacement therapy) if the contralateral ovary is removed. We modeled the probabilities of surgical complications, occult malignancy, development of contralateral adnexal pathology, surgical menopause, use of hormone replacement therapy, and development of ovarian cancer. The costs included surgical procedures, complications, ultrasound surveillance, hormone therapy, and treatment of ovarian cancer, with information gathered from Medicare reimbursement data and published literature. Cost-effectiveness was determined using the incremental cost-effectiveness ratio of Δ costs / Δ deaths with a willingness-to-pay threshold of $11.6 million as the value of a statistical life. Multiple 1-way sensitivity analyses were performed to evaluate model robustness.

Our model demonstrated that unilateral salpingo-oophorectomy is associated with improved outcomes compared with surveillance, with fewer deaths (0.28% vs 1.50%) and fewer cases of ovarian cancer (0.42% vs 2.96%). However, it costs more than sonographic surveillance at $6403.43 vs $5381.39 per case of incidental endometrioma. The incremental cost-effectiveness ratio showed that unilateral salpingo-oophorectomy costs $83,773.77 per death prevented and $40,237.80 per case of ovarian cancer prevented. As both values were well below the willingness-to-pay threshold, unilateral salpingo-oophorectomy is cost-effective and is the preferred strategy. If unilateral salpingo-oophorectomy were chosen over surveillance for premenopausal patients with incidental endometriomas, 1 diagnosis of ovarian cancer would be prevented in every 40 patients and 1 death averted in every 82 patients. We performed 1-way sensitivity analyses for all input variables and determined that there were no reasonable inputs that would alter our conclusions.

Unilateral salpingo-oophorectomy is cost-effective and is the preferred strategy compared with surveillance for the management of incidental endometrioma in a premenopausal patient not desiring fertility. It incurs fewer deaths and fewer cases of ovarian cancer with costs below the national willingness-to-pay thresholds.