Recurrence potential of benign multiple and single endometrial polyps in premenopausal women—a prospective cohort study

Endometrial polyp(EP) is one of the most common intrauterine lesions which interfere with embryo implantation. It can be removed easily under hysteroscopic guidance, but its high recurrence rate is a real concern for patients planning to conceive. However, factors influencing the postoperative EP recurrence rate have limited data and whether polyp number is associated with increased risk of recurrence is controversial. The study aims to compare the recurrence rates of premenopausal patients with multiple and single EP and to identify prognostic factors for their recurrence potential. Prospective cohort study Premenopausal women who underwent hysteroscopic endometrial polypectomy in the First Affiliated Hospital of Sun Yat-sen University without subsequent hormone therapy were recruited from January 2015 to January 2016. All of them were awaiting a future pregnancy. They were divided into two groups based on the polyp numbers found during the hysteroscopic examination. Patients with over 6 polyps were enrolled as multiple EP group while those with single polyp were recruited as single EP group. All EPs were completely removed and the diagnosis were confirmed by histology. Patients' main demographic and clinical characgteristics were recorded and they were then followed to check for polyp recurrence by transvaginal ultrasound scan 3 months,6 months,9 months and 12 months after the operation. One hundred and one cases for multiple EP group and 81 single EP cases were enrolled. Patients’ ages were lower in the multiple group than in the single group(34.4±5.7 versus 36.75±6.4,P<0.05). Other baseline parameters were all comparable between two groups. After one year of follow up, 46% (95%CI, 34% -57% )of patients from multiple EP group had polyp recurrence, while only 13%(95%CI, 5%-22%) of patients recur in the single EP group, P<0.05. Furthermore ,the polyp recurrence rates from multiple EP group were also significantly higher than single EP group in each follow-up time intervals with 9.8% vs.1.3% after 3 months, 20% vs. 4.1% after 6 months and 33.1%vs.11.5% after 9 months.COX regression analysis revealed that multiple polyps (HR3.5, 95%CI 1.4-8.5, P<0.01), endometriosis (HR2.4,95%CI 1.1-5.4, P<0.05) and history of polypectomy (HR2.2,95%CI 1.0-4.6, P<0.05) were significantly predictors for polyp recurrence after polypectomy, while patients’ age, BMI, gravida, parity, polycystic ovary syndrome and leiomyoma were not associated with polyp recurrence. Multiple polyps, endometriosis and history of EPs were associated with a greater potential of polyp recurrence after hysteroscopic polypectomy. Patients with excessive growth of multiple EPs were much more vulnerable to polyp recurrence than those with single polyp, indicating that these two different types of polyps may possibly arise by a different etiology and pathogenesis.