Survival outcomes similar between minimally invasive interval debulking surgery and laparotomy

A minimally invasive approach to interval debulking surgery appears to be just as effective as the use of an open technique for epithelial ovarian cancer, with no significant difference in overall survival (OS) when complete tumour resection is achieved, according to a study.

In a large cohort of epithelial ovarian cancer patients from the US National Cancer Database, the median OS was 51 months in the minimally invasive group versus 46 months in the open surgery group (hazard ratio [HR], 1.10, 95 percent confidence interval [CI], 0.94–1.26; p=0.17), reported principal study investigator Dr Judy Hayek of SUNY Downstate Health Sciences University in Brooklyn, New York, US. [Hayek J, et al, SGO 2024]

The same held true across subgroup analyses, where there was no interaction between the extent of surgery and the impact of minimally invasive surgery on survival, Hayek continued. The median OS did not significantly differ between the minimally invasive group and the open surgery group among patients who underwent extensive surgery (p=0.55) and among those who underwent nonextensive surgery (p=0.23).

“Extensive surgery was more often performed in the open surgery group. It was also correlated with worse survival, and this was likely attributable to a greater disease burden,” she said.

Likewise, within the minimally invasive group, the median OS was similar between patients who underwent robot-assisted surgery and those who underwent laparoscopic surgery (52 vs 50 months, respectively; p=0.99).

Consistent with expectations, patients in the minimally invasive group had a significantly shorter length of hospital stay compared with those in the open surgery group (median 3.3 vs 5.3 days; p<0.001), with fewer deaths both at the 30-day (0.8 percent vs 1.6 percent; p=0.006) and 90-day (1.9 percent vs 3.5 percent; p=0.003) time points.

Concerns have been raised regarding the potential drawbacks of minimally invasive surgery, as Hayek noted. Some surgeons believe that the absence of haptic feedback and restricted view of the surgical field may lead to undetected residual disease and poorer survival outcomes in patients believed to have undergone complete gross resection.

But recent evidence suggests that a minimally invasive approach to interval debulking is safe and feasible. Hayek also noted an increasing trend in the adoption of minimally invasive surgery during the study period, from 11.9 percent in 2010 to 36.5 percent in 2019. [Am J Obstet Gynecol 2016;214:503.e1-503.e6; Int J Gynecol Cancer 2019;29:1341-1347]

The findings of the present study—despite the lack of data on patient-specific tumour burden and neoadjuvant chemotherapy used, among others—provide additional data that minimally invasive surgery yields comparable survival outcomes to open surgery.

The study included 2,412 patients who had complete gross resection during interval debulking surgery, which was performed via a minimally invasive approach in 624 (48.7 percent robot-assisted, 51.3 percent laparoscopic) and via an open technique in 1,788 (53.0 percent extensive surgery). Minimally invasive surgery cases that were converted to laparotomy were included in the open surgery group. Patients in the minimally invasive group were older (median age 66 vs 64 years; p=0.016) and less likely to undergo extensive surgery (41 percent vs 53 percent; p<0.001).

Potential for missing residual disease

In a separate presentation, Dr Kara Long Roche of Memorial Sloan Kettering Cancer Center in New York, New York, US, pointed out that the possibility of overlooking residual disease during interval debulking surgery is too great a risk, and its impact on patient outcomes is not up for debate.

“We know from almost every retrospective and prospective study done that the volume of residual disease after debulking, whether primary or interval, is the most important prognostic factor for our patients that we can modify,” Long Roche stated.

Instead of looking at morbidity, mortality, or criteria for resection, Long Roche argued that the central question of the debate should be: “Can minimally invasive interval debulking achieve an equivalent completeness of resection, as measured by the volume of residual disease, as traditional open surgery?”

The question, she said, cannot be answered by retrospective studies such as that by Hayek et al due to selection bias. “Patients selected for minimally invasive interval debulking … have better responses to neoadjuvant chemotherapy and better tumour biology. So, we have to ask whether survival really is an appropriate endpoint in the retrospective trials.”

Long Roche also pointed to the lack of universal criteria for resectability, saying that factors such as disease characteristics, patient health status, surgeon expertise, and institutional resources all contribute to the complexity of identifying patients with resectable disease via open surgery. “It’s going to be even more difficult to [do this for minimally invasive surgery].”

Moreover, she stressed that neoadjuvant chemotherapy is not a “waiver” of upper abdominal surgery, with data from over 10 years ago showing that roughly half of patients receiving neoadjuvant chemotherapy have bulky upper abdominal disease at the time of debulking.

Long Roche raised concerns about a phenomenon she called “We Never Looked.” She pointed to images in her presentation wherein disease in the Morrison’s pouch, porta, or behind the liver could be missed in a seemingly normal laparoscopic assessment of the upper abdomen.

Advocating for keeping interval debulking surgery radical, Long Roche concluded: “Minimally invasive interval debulking surgery should be the exception, not the rule. We need prospective data with appropriate endpoints. We need surgical quality control in both arms, and we need to continue to focus on surgical education and training so that our trainees can graduate doing these procedures via any approach.”