VANCOUVER, B.C. (FRONTLINE MEDICAL NEWS)The incidence of unsuspected uterine sarcoma found during surgery for other conditions is low, according to three cohort studies reported at the meeting, sponsored by AAGL.

In one study, researchers at Mount Sinai Hospital in New York City retrospectively studied 815 consecutive women who underwent laparoscopic supracervical hysterectomy or laparoscopic myomectomy with power morcellation at the hospital between 2006 and 2013.

Pathology of the morcellated uteri identified endometrial carcinoma in two patients (one with prolapse and one with a presumed prolapsing fibroid), for an incidence of 0.25%, according to Dr. Charles J. Ascher-Walsh, associate professor of obstetrics, gynecology, and reproductive science at Mount Sinai, and lead author of the study.

None of the patients were found to have a uterine sarcoma or any other cancer.

“There’s obviously very little data sort of looking forward on the risk of morcellating endometrial cancers. It doesn’t seem so far to significantly worsen the prognosis in these patients. There have been a few reviews looking at a cost-effectiveness analysis in biopsying postmenopausal asymptomatic patients who are having prolapse surgery, and so far the conclusions in both of those studies have shown that it’s not cost-effective to biopsy these patients,” Dr. Ascher-Walsh said. “Now I know there are institutions that are biopsying them anyway, and certainly as part of the revamp of people’s protocols with the morcellation debate, I think more institutions are starting to automatically biopsy every patient before morcellation.”

Total laparoscopic hysterectomies were not included in the study, because Dr. Ascher-Walsh usually performs that operation by vaginal approach, he said. “I wanted to focus just on the intra-abdominal morcellation technique. But obviously, in the debate, whether you cut into it vaginally or cut into it with an open myomectomy, you can potentially have the same concerns and risks.”

Mount Sinai has modified its policy on performing morcellation, somewhat, as a result of the ongoing debate, Dr. Ascher-Walsh said.

“We continue to do morcellation, but before doing morcellation, if we don’t have documentation of a typically growing fibroid, or if somebody presents with a large fibroid without any evidence of slow growth over time, we will get an MRI, although the evidence isn’t supportive of MRIs being diagnostic, other than the one study that combined it with [lactate dehydrogenase],” he said.

In the second study, a team led by Dr. Nichole Mahnert, a fellow in obstetrics and gynecology at the University of Michigan, Ann Arbor, used the Michigan Surgical Quality Collaborative database to prospectively study 6,360 women who underwent hysterectomy for a benign indication during 2013.

Pathology identified unexpected uterine sarcoma in 0.22% of patients (1 in 454) overall, and in 0.27% of patients (1 in 370) whose indication for surgery was specifically fibroids. These values are generally on par with the 0.28% of women operated on for fibroids (1 in 352) seen in the Food and Drug Administration assessment , she said.

In the cohort overall, prior venous thromboembolism and preoperative blood transfusion tended to be more common among patients later found to have uterine sarcoma.

Other cancers identified in the entire cohort included endometrial cancer (1.02%), ovarian cancer (1.06%), cervical cancer (0.17%), and metastatic cancer (0.20%).

“Comprehensive preoperative surgical counseling is paramount, and it should include not only the usual risks of surgery, but also the risk of unexpected malignancy and the risk of inadvertent morcellation of an unexpected malignancy. One should also consider the risks and benefits of a laparoscopic versus and open procedure,” Dr. Mahnert recommended. “And until we can more reliably risk-stratify patients to identify those with unexpected uterine sarcomas, we need to support technologies to limit the dissemination of specimens during minimally invasive procedures.”

In the third study, Dr. Katherine A. Hartzell, an ob.gyn. at Kaiser Permanente in San Diego, and her colleagues retrospectively reviewed the charts of all 3,523 women undergoing laparoscopic hysterectomy at the institution between 2001 and 2012.

Of the 941 cases in which power morcellation was used, uterine sarcoma was found in 6 cases or 0.6%; half were endometrial stromal sarcoma and half were leiomyosarcoma. Five of these patients had no evidence of disease after at least 31 months of follow-up. The sixth patient, who had high-grade leiomyosarcoma, died from her disease 3 years after diagnosis.

The uterine sarcoma rate of 0.6% was roughly double the 0.28% estimated by the FDA, Dr. Hartzell noted.

“This higher incidence was probably due to the inclusion of three patients with a delayed presentation of uterine sarcoma when initial pathology was benign,” she said. “These patients were likely discovered because of the captive nature of the Kaiser health care system.”

None of a wide variety of factors evaluated predicted the risk of uterine sarcoma in these patients undergoing morcellation, Dr. Hartzell said.

Among the 2,582 women who did not undergo power morcellation, uterine sarcoma was identified in 5 patients, or 0.2%. Four were alive without evidence of disease after at least 37 months of follow-up. The fifth patient, who had high-grade leiomyosarcoma, died from her disease 2 years after diagnosis.

“The patient about to undergo a minimally invasive procedure with possible power morcellation should be counseled about the possible consequences of morcellation of an undiagnosed malignancy. Alternatives such as mini-laparotomy or an open procedure should be offered. At our institution, we are also now performing morcellation within a tissue containment bag,” she said.

“Given the well-known advantages of laparoscopic surgery and the rarity of uterine sarcomas, it is our opinion that the risk of morcellation of occult malignancy is insufficient to abandon power morcellation,” Dr. Hartzell added.

The researchers reported that they had no relevant conflicts of interest.