Secondary cytoreductive surgery extends OS, PFS in advanced ovarian cancer
Secondary cytoreductive surgery conferred significant and clinically meaningful OS and PFS benefits for selected women with recurrent ovarian cancer, according to phase 3 study results presented during the ASCO20 Virtual Scientific Program.
“Secondary cytoreductive surgery has been used for decades; however, the evidence behind it was sparse. As surgery has potential side effects, a better definition of the risk-benefit balance was needed,” Andreas du Bois, MD, professor of gynecologic oncology at Kliniken Essen-Mitte in Germany, told Healio.
“Our study, DESKTOP III, showed that thoroughly selected patients treated in high-quality centers experience a significant and clinically meaningful survival benefit when secondary cytoreductive surgery rendered a complete resection — the latter of which was the case in 75% of selected patients,” he added. “These benefits exceed the benefit seen in any other trial so far and should not be withheld from these patients.”
The current study was based on the DESKTOP I and DESKTOP II studies, in which researchers used a biomarker score, dubbed AGO score, to select women who may benefit the most from cytoreductive surgery — those with a good performance status (ECOG performance score of 0), complete initial resection during first-line therapy and ascites not exceeding 500 mL.
DESKTOP II confirmed the utility of the score, which identified more than half (51%) of women with platinum-sensitive recurrent ovarian cancer and predicted complete resection among those women with very high probability.
The prospectively randomized DESKTOP III study included 407 women with recurrent ovarian cancer who relapsed after a platinum-free interval of 6 months or more and had a positive AGO score. The women received second-line chemotherapy alone (n = 201; median age, 62.2 years) or secondary cytoreductive surgery followed by chemotherapy (n = 206; median age, 60.8 years). Researchers recommended platinum combination therapy.
OS served as the primary endpoint. PFS, resection rate and treatment burden served as secondary endpoints.
The platinum-free interval prior to study entry exceeded 1 year for 75% of women. Nearly 90% of women in both groups received platinum-containing second-line chemotherapy.
Among the women assigned to the surgery group, 91% underwent surgery and 75% achieved complete resection.
Results of the primary endpoint analysis showed median OS of 53.7 months in the surgery group vs. 46 months in the group that received chemotherapy without surgery (HR = 0.75; 95% CI, 0.58-0.96).
“The OS benefit was highest and exclusively seen in the cohort with complete resection, indicating the importance of a thorough selection process of both the right patient and center,” du Bois said.
The surgery group also had longer median PFS (18.4 months vs. 14 months; HR = 0.66; 95% CI, 0.54-0.82) and time to start of first subsequent therapy (17.9 months vs. 13.7 months; HR = 0.65; 95% CI, 0.52-0.81) than the no-surgery group.
In an analysis according to treatment, researchers observed an OS benefit that exceeded 1 year for women who achieved complete resection with surgery vs. women who did not undergo surgery (60.7 months vs. 46 months). Women who underwent surgery with incomplete resection had shorter median OS (28.8 months).
“That translates to a risk reduction of complete resection vs. incomplete resection of 60%, which is highly significant,” du Bois said during the presentation.
Sixty-day mortality rates were 0.5% in the no-surgery group vs. zero in the surgery group. In addition, 3.7% of women who underwent surgery had re-laparotomies.
“The score developed within the series of DESKTOP III studies is the first predictive score in ovarian cancer that predicts survival benefit for a certain therapy,” du Bois told Healio. “However, only three out of four patients experienced the benefit and 25% were selected but failed to benefit. Therefore, we need to refine the tools for predicting benefit and better define the patient population who might experience the greatest benefit. In addition, we need to provide transparent quality criteria for centers to support patients’ selection of an adequate treatment facility.”