Use of Electric Power Morcellation and Prevalence of Underlying Cancer in Women Who Undergo Myomectomy.

IMPORTANCE Myomectomy, the excision of uterine leiomyoma, is now commonly performed via minimally invasive surgery. Electric power morcellation, or fragmentation of the leiomyoma with a mechanical device, may be used to facilitate extraction of the leiomyoma. OBJECTIVE To analyze the prevalence of underlying cancer and precancerous changes in women who underwent myomectomy with and without electric power uterine morcellation. DESIGN, SETTING, AND PARTICIPANTS We used a US nationwide database to retrospectively analyze women who underwent myomectomy at 496 hospitals from January 2006 to December 2012. Use of electric power morcellation at the time of myomectomy was investigated. The prevalence of uterine cancer, uterine neoplasms of uncertain malignant potential, and endometrial hyperplasia were estimated. Multivariable mixed-effects regression models were developed to examine predictors of use of electric power morcellation and factors associated with adverse pathologic outcomes. MAIN OUTCOMES AND MEASURES Use of electric power morcellation at the time of myomectomy was examined. The occurrence of uterine cancer and precancerous uterine lesions was determined. RESULTS The cohort consisted of 41 777 women who underwent myomectomy at 496 hospitals and included 3220 (7.7%) who had electric power morcellation. Uterine cancer was identified in 73 (1 in 528) women who underwent myomectomy without electric power morcellation (0.19%; 95% CI, 0.15%-0.23%) and in 3 (1 in 1073) women who underwent electric power morcellation (0.09%; 95% CI, 0.02%-0.27%). The corresponding rates of any pathologic finding (cancer, tumors of uncertain malignant potential, or endometrial hyperplasia) were 0.67% (n = 257) (95% CI, 0.59%-0.75%) (1 in 150) and 0.43% (n = 14) (95% CI, 0.21%-0.66%) (1 in 230), respectively. Advanced age was the strongest risk factor for uterine cancer. CONCLUSIONS AND RELEVANCE The prevalence of cancers and precancerous abnormalities of the uterus in women who undergo myomectomy with or without electric power morcellation is low overall, but risk increases with age. Electric power morcellation should be used with caution in older women undergoing myomectomy.