Drs. Maria Cusimano and Sarah Ferguson
Cervical cancer and surgical approach study leads, Drs. Maria Cusimano (L) and Sarah Ferguson, discussed their study results at this year's Department of Obstetrics & Gynecology, U of T, Research Day. (Photo: Courtesy Faculty of Medicine, University of Toronto)

A "real-world" study of Ontario early-stage cervical cancer patients has shown that there is a two-fold higher rate of death and recurrence in patients who had minimally invasive surgery (MIS) compared to those who had traditional, open surgery for a radical hysterectomy.

This first-ever large Canadian study was able to confirm these findings even after accounting for the volumes of patients surgeons treated, and surgeons' experience with the procedure.

Led by Princess Margaret Cancer Centre and University of Toronto clinician-researchers Drs. Maria Cusimano and Sarah Ferguson, the study confirmed 2018 findings published in the New England Journal of Medicine, which showed that there is harm associated with using the MIS approach for a radical hysterectomy for early stage cervical cancer – an approach widely used for a decade until these findings questioned it's safety.

The Ontario data showed the dramatic increase in using MIS for cervical cancers: the proportion of cases rose from 4.8 per cent of all hysterectomies in 2006 to 65 per cent in 2017.

"These studies showed the opposite of what everyone was anticipating," said Dr. Cusimano, the lead author, who has paused her surgical residency in Obstetrics & Gynecology to complete a PhD in Clinical Epidemiology. "Surgeons believed that minimally invasive radical hysterectomy was safe because the MIS approach was safe for many other cancers, such as endometrial cancer."

As a result of these studies, the MIS procedure is no longer used at UHN for radical hysterectomies in patients with early stage cervical cancers.

An estimated 1,550 Canadian women were diagnosed with cervical cancer in 2017, with an estimated 400 deaths. Many women with early-stage disease are treated with radical hysterectomy, which means removing the uterus, cervix, and surrounding tissues.

Those with advanced cervical cancer are usually treated with radiation and chemotherapy.

Next steps include understanding why the link exists

The Canadian study was published online July 6 in the American Journal of Obstetrics and Gynecology. Read more about the study.

Both Drs. Cusimano and Ferguson emphasized that the results refer only to a small proportion of patients with a specific stage of cervical cancer who need a radical hysterectomy. They do not apply to the use of MIS hysterectomy for endometrial cancer or other non-cancerous gynecologic conditions, which remain safe.

Using Ontario-wide records, the study examined the outcomes of 958 patients in Ontario, who either underwent MIS or an open surgery for a radical hysterectomy from 2006 to 2017, with a follow-up of about six years.

Deaths occurred in 12.5 per cent of those receiving MIS in contrast to 5.4 per cent of those receiving traditional, open surgery by five years after their surgery. Recurrence of the cancer at five years after surgery occurred in 16.2 per cent of patients receiving MIS, compared to 8.4 per cent of those who had open surgery.

After learning about the 2018 results questioning the safety of the MIS approach for early-stage cervical cancer patients at an international conference, Drs. Cusimano and Ferguson resolved to see if those results were similar to what was happening in Ontario by examining "real-world" data.

Within a month, Drs. Ferguson and Cusimano had secured a grant from the Rose Torno Chair Award, Department of Obstetrics and Gynecology at Mount Sinai Hospital/University Health Network, to begin their work.

"Performing randomized studies in surgical oncology for rare cancers is extremely challenging," reflected Dr. Ferguson, who is also the Director of Research for the Division of Gynecologic Oncology, UHN. "It takes a team with strong conviction to find funding and pull it together against all odds. You have to hold yourself to a high standard and be persistent and the investigators of the international 2018 trial should be congratulated.

"All of this work is motivated by the women we care for on a daily basis. When you're asking for consent for a surgical procedure, you have to look patients in the eye and make sure they get the best possible outcomes."

Next steps for Drs. Cusimano and Ferguson will be to collect pathology reports to understand why this link exists in a subset of these early-stage cancers, and whether altering the MIS technique makes a difference in outcomes.

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