The benefit of minimally invasive surgery in terms of minimized pain and shorter recovery times is well established, and there is a trend toward increasing the use of minimally invasive procedures for a variety of gynecologic surgeries, including fibroid removal and hysterectomy.
Many of these surgeries depend on morcellation—the division and removal of small pieces of tissue, traditionally by hand but today more likely using a motorized instrument—which allows for larger amounts of tissue to be removed laparoscopically.1
A downside of morcellation is that as a result of the process, bits of tissue may be unavoidably seeded throughout the intra-abdominal area, where they may revascularize and grow. The risk of unanticipated or unidentified malignant tissue taking root elsewhere in the abdomen is low, but is not negligible, as recent studies have highlighted.1-4
The Effect of Morcellation on ULMS Outcome
Unfortunately, there are no accurate tools available to distinguish benign leiomyomas (usually fibroids) from malignant growths such as leiomyosarcomas prior to the procedure. This means the presence of malignancy generally is not established until pathology review after surgery.2-4
In a case series from Brigham and Women’s Hospital in Boston, MA, the aggregate incidence of unsuspected atypical or malignant tissue following morcellation of suspected leiomyoma was 1.2%, including seven women with uterine leiomyosarcoma (ULMS).1
ULMS arises in the myometrium and accounts for approximately 2% of cancers of uterine origin.5 ULMS is associated with poor 5-year survival, especially when diagnosed at more advanced stages; a recently updated case series found median overall survival (OS) for patients with ULMS ranged from 75 months with stage 1 to 20 months with stage 4.2,5,6 Tumor morcellation has an additional negative effect on both disease-free survival and OS.4,7,8
The impact of morcellation on ULMS survival likely can be attributed to unintentional dissemination of malignant tissue during procedures for suspected benign fibroids. Women undergoing morcellation procedures are significantly more likely than those not having morcellation to have evidence of tumor dissemination upon follow-up; in a 2011 published series of 56 consecutively assessed women, pelvic dissemination was found in 44% of women who had morcellation versus 12.9% of those who did not (P=0.032).7
In another recent series, 28.6% (two of seven) of patients with presumed stage 1 ULMS detected after morcellation were found to have peritoneal dissemination upon surgical re-exploration about a month after morcellation, leading to upstaging of their disease.4
In another series, 63.4% (nine of 14) of women who underwent a morcellation procedure were found to have peritoneal dissemination; seven of these women were diagnosed with ULMS after their initial surgery.1 Peritoneal dissemination was highly associated with mortality, as shown in Figure 1.1
Figure 1. Clinical outcome of patients with unsuspected uterine leiomyosarcoma (ULMS) detected after electric uterine morcellation (EUM).1
How Substantial Is the Risk for Malignant Dissemination?
Two articles in the February 6 issue of the Journal of the American Medical Association address concerns about the increased risk for spread of malignant tissue during procedures using electric morcellation.2,3 These studies note that although women generally are advised that the risk of undetected malignancy with fibroids is about one in 10,000, a case series from Boston, MA found a substantially higher rate of approximately 1%.1,2
Women should be informed of the possibility that morcellation can spread cancer cells if they are present, and the risk should be put into context based on the findings of these case series and the potential for harm represented by the spread of ULMS.
Additional risk mitigation can be achieved by adopting methods that minimize the risk of dissemination with morcellation, such as using an endoscopic bag to contain the fibroid during morcellation, or by considering alternatives, including open surgery.3,9