Woman whose ovarian cancer returns more than six months after initial surgery and chemotherapy may benefit from a second surgery, but only if the entire tumor is removed during the procedure, data from a clinical trial show.

Patients should be carefully selected for a second surgery, based on the likelihood that this surgery will successfully remove the entire cancer, its researchers said.

These data were presented at the American Society of Clinical Oncology (ASCO) 2020 annual meeting, which was held virtually due to the COVID-19 pandemic. The presentation, “Randomized phase III study to evaluate the impact of secondary cytoreductive surgery in recurrent ovarian cancer: Final analysis of AGO DESKTOP III/ENGOT-ov20,” was given by Helen MacKay, MD, of the University of Toronto.

Recurrent ovarian cancer refers to cancer that was initially treated successfully (e.g., removed through surgery), but that then returned (recurred). How best to treat recurrent ovarian cancer — whether by surgery, medication, chemotherapy, or combinations of treatments — remains an ongoing area of research.

“The topic of secondary surgery is not a new one,” MacKay said in a news story, adding that secondary surgery for recurrent ovarian cancer is recommended in guidelines issued by the National Comprehensive Cancer Network. The effectiveness of such surgery, however, is still debated.

These new data come from the completed DESKTOP III clinical trial (NCT01166737), in women with recurrent ovarian cancer who met specific criteria. They had gone at least six months without chemotherapy before the recurrence, and had a positive Arbeitsgemeinschaft Gynaekologische Onkologie (AGO) score. This score is a predictor of how easily a recurrent tumor can be operated on; a positive score includes factors like low amounts of fluid in the tumor, and complete removal of the tumor in the initial surgery.

Andreas Du Bois, a DESKTOP III researcher and professor at Kliniken Essen Mitte in Germany, states in a video post for Ecancer that about half of patients with recurrent ovarian cancer have a positive AGO score.

DESKTOP III enrolled 407 patients across 80 centers in 12 countries, who were randomly assigned to either secondary surgery plus platinum-based chemotherapy or this chemotherapy alone.

Almost all patients in the surgery group, 91%, actually underwent a second surgery, and 75% of them achieved a complete resection — that is, the entire tumor was removed. In both groups, about 90% of enrolled patients were given platinum-based chemotherapy.

The median overall survival was significantly higher in the surgery group (53.7 vs. 46.2 months). Secondary surgery also significantly extended the time patients lived without disease worsening (median of 17.9 months) compared with chemo alone (13.7 months).

Within the surgery group, those who had a complete resection (CR) had a notably higher median overall survival time — 60.7 months, over a year longer than the chemo group. However, median overall survival for those in the surgery group who did not have complete resection was significantly lower (28.8 months).

The survival benefit was exclusively seen in patients with complete resection, the researchers wrote, “indicating the importance of both the optimal selection of patients (eg. by AGO score) and of centers with expertise and a high chance of achieving a CR.”

“The crucial thing about secondary surgery is both the selection of the right center and selection of the right patient,” du Bois said in the video post. “If both fits, then this offers an opportunity to improve life, quality of life, and length … of overall survival in these patients.”

“This is the first trial to demonstrate an overall survival benefit of surgery in recurrent, platinum-sensitive disease,” MacKay said, emphasizing that decisions about surgery still need to be made based on the circumstances of individual patients.

Further understanding of exactly which people are most likely to benefit from surgery (using tools like the AGO score) will ultimately be necessary for optimal care, she added.

“Perhaps there is further optimization to be achieved with extending criteria, and I know that in certain centers this is already being done,” MacKay said.