Long-term risk of uterine malignancies in women with uterine fibroids confirmed by myomectomy: a population-based study

Leiomyosarcomas may originate from pre-existing uterine fibroids. However, recent studies showed that leiomyosarcomas do not arise from malignant changes in fibroids. Epidemiological data on the long-term risk of uterine malignancy with uterine fibroids are lacking. We aimed to determine whether uterine fibroids are a risk factor for uterine cancer. Patient data (2007-2020) from the Korean Health Insurance program were obtained. Using the procedure and diagnostic codes, data from patients who underwent myomectomy and appendicitis (control group) were extracted Using 1:1 propensity-score matching, 84,507 women were each allocated to the uterine fibroids and control groups. Endometrial cancer occurred in 36 44 and 44 36 women in the uterine fibroids and control groups (p = .371), respectively; 6/36 46 and 4 5/44 37 cases of uterine corpus cancer sarcoma occurred in the respective groups. Total uterine cancer (excluding cervical cancer) occurred in 46 and 39 37patients in the uterine fibroids and control groups, respectively (p = .323). A higher risk of uterine malignancy was not found in women with uterine fibroids confirmed by myomectomy. If surgery is indicated, a myomectomy can be safely performed without increasing the cancer risk. IMPACT STATEMENT What is already known on this subject? Traditionally, leiomyosarcomas were considered to originate from pre-existing uterine fibroids. However, recent studies suggest that leiomyosarcomas do not arise from the malignant change of fibroids. Meanwhile, there is a dearth of real-world evidence on the risk of uterine cancer in patients with uterine fibroids. What do the results of this study add? No evidence of a higher risk of uterine malignancy was found in women having uterine fibroids confirmed by myomectomy in this population-based study. In our cohort of women with uterine fibroids, tissue injury by myomectomy does not appear to cause malignant transformation. What are the implications of these findings for clinical practice and/or further research? Uterine fibroids doesn't appear to be a risk factor for uterine malignancies, and tissue injury by myomectomy does not appear to cause malignant transformation. If surgery is indicated, myomectomy can be performed safely, given that the long-term risk of uterine malignancy does not increase.