Risks of Malignancy among 11,204 Patients with Endometrial Polyp: A Systematic Review and Meta-analysis

To evaluate factors associated with malignancy in patients with endometrial polyps.

We conducted electronic database research on PubMed, MEDLINE, EMBASE, COCHRANE, and Google Scholar from inception for all studies on endometrial polyp. After removing duplicates, and title and abstract screening, we had a total of 121 articles and 151 others from screening the reference list. Inclusion criteria included peri and postmenopausal women > 45 years diagnosed histopathologically with endometrial polyp(s). We excluded women with a history of endometrial cancer or hysterectomy.

Twenty studies were analyzed. Of 11204 patients with endometrial polyp, 287 had malignant polyps (2.75%), 182 (1.8%) had concomitant endometrial hyperplasia with atypia, and 520 (5.2%) had hyperplasia without atypia within the polyp. Menopausal women had a higher risk of pre-malignancy/malignancy than non-menopausal women (OR 5.63 (95CI 3.87, 8.20, I ² = 0%, P < 0.001). Endometrial thickness on ultrasound in pre-malignancy/malignancy cases was significantly thicker than in the benign polyp (mean difference 4.2 mm, 95% CI 0.8 to 7.6 mm, I ² = 18%, P = 0.02). Women who used tamoxifen or hormone replacement therapy (HRT) had a lower likelihood of endometrial pre-malignancy/malignancy, while women with abnormal uterine bleeding (AUB) had a higher probability of pre-malignancy/malignancy. The odd ratio of having pre-malignancy/malignancy among those who used tamoxifen was 0.50 (95% CI 0.26-0.94: I ² 12%, p = 0.03).

In women with endometrial polyp, menopausal age and thickened endometrium might increase the probability while tamoxifen or HRT use might lower the likelihood of endometrial pre-malignancy/malignancy; and the presence of AUB might signal endometrial pre-malignancy/malignancy.