The CHORUS trial had similar results to the previous European Organisation for Research and Treatment of Cancer (EORTC) 55971 study, showing noninferiority for primary debulking surgery followed by chemotherapy vs neoadjuvant chemotherapy followed by surgery and additional chemotherapy, said formal discussant Jonathan S. Berek, MD, Director of the Stanford Women’s Cancer Center, Palo Alto, California. Both studies showed an optimal debulking rate of about 41% for primary surgery vs 75% to 80% in the neoadjuvant chemotherapy arms. Dr. Berek emphasized, however, that the two trials had slightly different patient populations, with more poor-prognosis and older patients in CHORUS.

“Both trials included a sicker group of patients. One needs to consider these factors in selecting patients for neoadjuvant therapy vs cytoreduction,” he said.

He noted that an ongoing Japan Clinical Oncology Group (JCOG) trial is comparing eight cycles of chemotherapy following surgery vs four cycles of neoadjuvant chemotherapy, surgery, and four more chemotherapy cycles, but results of that trial won’t be available until 5 years from now.

Impact of Where Surgery Is Done

The extent of debulking is controversial and depends on the country where the study was conducted, he continued. Also, the high postoperative mortality rate in the primary surgery arm of CHORUS is of concern, and was probably related to the center where surgery was performed.

“In the EORTC trial, optimal debulking rates and hazard ratios varied considerably by country. The extent and quality of resection may impact outcome,” he said.

“In the future, patient selection [for neoadjuvant chemotherapy vs primary debulking surgery] will be critical. We will need to develop tools to predict which patients will do poorly with primary surgery. These findings are not generalizable to all patients with stage III ovarian cancer. My belief is that good-prognosis patients should be treated with primary surgery followed by chemotherapy,” he stated. ■

Disclosure: Dr. Berek reported no potential conflicts of interest.