Secondary Surgery Extends OS in Recurrent Ovarian Cancer

Neil Osterweil

June 04, 2020

In a phase 3 trial, combining cytoreductive surgery with chemotherapy significantly prolonged progression-free and overall survival among select patients with recurrent ovarian cancer who had a platinum-free interval of more than 6 months.

The trial, AGO DESKTOP III/ENGOT ov20, is the first prospective, randomized study showing an overall survival benefit for debulking surgery in patients with recurrent ovarian cancer.

Among 406 patients in first relapse, the median overall survival was 53.7 months for those randomized to cytoreductive surgery plus chemotherapy and 46 months for patients randomized to chemotherapy alone (P = .02).

"The overall survival 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 the right center," said investigator Andreas du Bois, MD, of the Kliniken Essen-Mitte (Germany).

The median survival gain for patients with platinum-free intervals of more than 6 months who undergo complete resection is nearly 16 months "and is worth going for," he added.

Dr. du Bois presented these results as part of the American Society of Clinical Oncology virtual scientific program (Abstract 6000).

In another trial, SOC-1, that was also presented in the virtual program, investigators reported a progression-free survival advantage of 5.5 months for patients with recurrent ovarian cancer who underwent debulking surgery, compared with those who did not (Abstract 6001).

Different Trials, Different Results

The invited discussant for Dr. du Bois's presentation was Robert L. Coleman, MD, chief scientific officer of the U.S. Oncology Network in The Woodlands, Tex., who was the principal investigator of the GOG-0213 trial (N Engl J Med. 2019;381:1929-39).

That trial did not show an overall survival advantage to secondary surgical cytoreduction followed by chemotherapy, compared with chemotherapy alone, among 485 women with platinum-sensitive recurrent ovarian cancer.

Referring to both AGO DESKTOP III and SOC-1, Dr. Coleman noted that, "while only DESKTOP III met its primary endpoint of improving overall survival, both demonstrated a benefit on PFS [progression-free survival]." Both trials also support a triage algorithm for selecting the approximately 75% of patients who are likely to benefit from secondary cytoreductive surgery.

"However, the price paid for being wrong is substantial, with no benefit seen in progression-free survival and possibly a detriment in overall survival. Because of these observations, both [presenters of SOC-1 and AGO DESKTOP III data] recommended that procedures be limited to select women having surgery performed at sites of excellence," Dr. Coleman said.

Potential explanations for the differential findings of a secondary surgery benefit in DESKTOP III and SOC-1 versus GOG-0213 include the use of a selection algorithm in the former versus investigator selection based on clinical parameters and imaging in the latter.

In addition, "while platinum-based therapy was the rule in all trials, the use of concomitant and maintenance bevacizumab, a regimen found to improve overall survival in GOG-0213, was used in substantially higher numbers of patients in that trial relative to the two current trials," Dr. Coleman said.

The GOG-0213 trial also demonstrated an advantage for adjuvant therapy with platinum-based chemotherapy and bevacizumab, which was given to 84% of patients in GOG-0213. That trial had a median overall survival for patients who did not undergo surgery of 65.7 months, compared with 46 months in AGO DESKTOP III and 53.9 months in SOC-1, Dr. Coleman said.

Third Time's a Charm

As its name implies, the AGO DESKTOP III trial is the third in a series. AGO DESKTOP I developed the hypothesis that a positive AGO score – consisting of an Eastern Cooperative Oncology Group performance status score of 0, complete resection during first-line therapy, and ascites less than 500 mL – could be predictive of favorable outcomes with debulking surgery (Ann Surg Oncol. 2006 Dec;13[12]:1702-10).

AGO DESKTOP II was a prospective, multicenter trial testing the score in patients with platinum-free intervals of more than 6 months (Int J Gynecol Cancer. 2011 Feb;21[2]:289-95). In this trial, 51% of patients had a positive AGO score, and the score was shown to predict, with 95% probability, complete resectability in two-thirds of these patients, Dr. Du Bois said.

In AGO DESKTOP III, 407 patients were prospectively randomized to second-line chemotherapy alone (n = 201) or to cytoreductive surgery (n = 206) followed by the same chemotherapy, with platinum-containing regimens highly recommended.

Patient characteristics were well balanced between the arms. Nearly all patients (99%) in each arm had prior platinum exposure, and 75% had a platinum-free interval of more than 12 months (a median of 21.1 months in the surgery arm versus 18.7 months in the no-surgery arm).

Complete Resections Extend OS

There were 8 patients (4%) in the chemotherapy-only arm and 14 (6.8%) in the surgery arm who were noncompliant with randomization. The complete resection rate was 74.2%.

Following randomization, 88.8% of patients in the surgery arm and 90% in the no-surgery arm received platinum-containing chemotherapy; 22.8% and 23.4%, respectively, received bevacizumab; and 3.9% and 6.0% received a poly (ADP-ribose) polymerase inhibitor.

The median overall survival in the intention-to-treat population was 53.7 months in the surgery arm and 46 months in the no-surgery arm, an absolute difference of 7.7 months (hazard ratio, 0.75; P = .02).

The median progression-free survival, assessed in the intention-to-treat population after database closure in January 2020, was 18.4 months with surgery and 14 months without (HR, 0.66; P < .001).

A post hoc analysis showed the importance of complete versus partial resection. The median overall survival was 61.9 months in patients with complete resections and 28.8 months for patients with residual tumor after cytoreductive surgery, an absolute difference of nearly 3 years (HR, 0.40; P < .001).

Comparing only those patients with complete resections with patients who did not undergo surgery, the respective median overall survival was 61.9 months and 46 months (HR, 0.57; P < .001).

AGO DESKTOP III was sponsored by the AGO study group in collaboration with other oncology groups, Medac, and GlaxoSmithKline. Dr. du Bois and Dr. Coleman disclosed relationships with many companies.

SOURCE: du Bois A et al. ASCO 2020, Abstract 6000.

This story originally appeared on MDedge.com.

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