Incidence of sarcoma in patients undergoing hysterectomy for benign indications: a population-based study

Minimally invasive hysterectomy may require the use of morcellation to remove the uterus. In the presence of unexpected sarcoma, morcellation risks disseminating malignant cells and worsening survival outcomes. As a consequence, in 2014 the US Food and Drug Administration issued a black box warning against the use of power morcellator for the treatment of uterine fibroids. However, the proportion of unexpected sarcoma at the time of hysterectomy for presumed benign indication remains unclear.

The objective of the study was to estimate the incidence of sarcoma among women undergoing hysterectomy for benign indication in Olmsted County, MN, between 1999 and 2013.

We conducted a population-based study including all hysterectomies performed for benign indication in Olmsted County women between Jan. 1, 1999, and Dec. 31, 2013. Cases were identified using the medical records-linkage system of the Rochester Epidemiology Project, and data were abstracted by a gynecologist who reviewed the complete medical records of each woman who underwent hysterectomy. An expert pathologist reviewed the pathologic slides of each sarcoma to ensure the accuracy of the diagnosis. Incidences of sarcoma (overall and by type of sarcoma) were estimated both overall and stratified by menopausal status, indication for surgery, and uterine weight as a rate per 100 persons.

A total of 4232 hysterectomies were performed during the study period. Among them, we identified 16 sarcomas, of which 11 (69%) were suspected preoperatively and 5 (31%) were unexpected. Of the total number of hysterectomies, 3759 (88.8%) were performed for benign indication. Among those, the incidence of unexpected sarcoma was 0.13% (5 per 3759 [95% confidence interval, 0.04-0.31%]). Uterine fibroids comprised 27.3% of all hysterectomies for benign indication (n = 1025) and was the indication most commonly associated with diagnosis of unexpected sarcoma. The incidence of unexpected sarcoma among surgeries for uterine fibroids was 0.35% (3 of 851) for premenopausal women and 0.57% (1 of 174) for peri/postmenopausal, and all 4 unexpected sarcomas were leiomyosarcoma. The incidence of unexpected sarcoma progressively increased with higher uterine weight with an incidence of 0.03% (1 of 2993) among women with a uterine weight <250 g vs 15.4% (2 of 13) with a uterine weight ≥2000 g.

Unexpected uterine sarcoma was low in all women undergoing hysterectomy for benign indication (0.13% or 1 in 752 surgeries) while it was increased in women with uterine fibroids (0.39% or 1 in 256 surgeries). Peri/postmenopausal women, women with large uteri, and age ≥45 years were risk factors for sarcoma.