Hospitals that perform many ovarian cancer surgeries tend to have better treatment outcomes in terms of mortality, a study suggests.

But restricting this surgery to only high-volume hospitals would greatly limit treatment availability while only meagerly increasing survival rates, the researchers say.

The study, published in the journal Obstetrics & Gynecology, is titled “Potential Consequences of Minimum-Volume Standards for Hospitals Treating Women With Ovarian Cancer.”

Ovarian cancer surgery comes with a high risk of complications, and prior research has suggested that institutions that perform many of these surgeries tend to report better results. Intuitively, this suggests that having a few hospitals that do many such surgeries would lead to the highest survival rates. While that may true, the practicality of such a system is questionable, researchers say.

“There’s a strong rationale for implementing minimum-volume standards at hospitals that perform cancer surgeries,” because they are “large procedures that require experience and a very specialized skill set,” Jason Wright, MD, a professor at Columbia University and co-author of the study, said in a press release. “But while some hospital systems are voluntarily implementing minimum-volume standards, we haven’t determined the optimal volume for hospitals performing complex cancer procedures or how applying minimum-volume standards would affect access to care.”

This is of particular import for women living in more rural areas, who may not have easy access to hospitals that do a lot of ovarian cancer surgeries, Wright said.

Wright and his colleagues analyzed data from the National Cancer Database, which included information on 136,196 women diagnosed with ovarian cancer between 2005 and 2015, and treated at 1,321 hospitals.

The researchers compared the treatment outcomes that were actually observed with the outcomes that would be expected based on the characteristics of the patients treated at the different hospitals. They also modeled how removing hospitals that treated fewer patients would be predicted to affect treatment outcomes.

Many of the hospitals included in the analysis performed relatively few ovarian cancer surgeries. Specifically, about a third (34.5%) performed less than three per year. On average, low-volume hospitals had slightly worse-than-expected mortality outcomes at 60 days, 1 year, 2 years, and 5 years after surgery.

Hospitals that performed only three surgeries per year had a 2% increase in mortality in the first year, and 3% within 5 years.

However, this distinction was just an average, not a universal feature of low-volume hospitals. The researchers noted, for example, that 51% of hospitals that did three or fewer surgeries per year had lower-than-expected two-year mortality rates. This suggests that patients treated at these hospitals aren’t at a higher risk of death than they would otherwise be.

Importantly, the researchers’ models predicted that eliminating the 34.5% of hospitals doing less than three surgeries per year would remove easy access to care for the 7.7% of ovarian cancer patients treated at these hospitals. And, within the first year after surgery, this would only prevent about one death for every 300 patients treated.

“Our study shows that hospitals considering implementing minimum-volume standards for cancer surgery could unintentionally prevent many patients from getting timely care for a minimal increase in survival,” Wright said.

“An arbitrary minimum-volume standard may be unnecessarily punitive for low-volume centers with good outcomes,” he added.