Study questions annual surgery volume limits in three types of cancer resections

Last Updated: 2019-12-19

By Gene Emery

NEW YORK (Reuters Health) - A new study is calling into question the wisdom of having hard-and-fast guidelines on how many complex operations a hospital needs to do to maximize survival in patients undergoing cancer resection.

The study, published in the Annals of Surgery, ranked hospitals by the frequencies with which they performed three surgeries - esophagectomy, proctectomy and pancreatectomy - and found that only the hospitals that performed the fewest complex cancer resections had significantly lower rates of 30- and 90-day survival.

The idea of concentrating difficult surgeries at regional centers with the most expertise is backed by research going back decades, suggesting the importance of day-to-day experience in treating specific types of problems.

But how much experience is necessary remains an open question. The concept of regional centers also carries potential threats to patients by forcing them to travel further to get care and ongoing therapy, or by fragmenting their care, especially among patients who are unwilling or unable to travel.

"What our data demonstrate is that there is likely more to good postoperative outcomes than just hitting that annual average," Dr. Nader Massarweh of the Baylor College of Medicine in Houston, Texas, told Reuters Health by email. "It may be less about the number itself and actually about the other resources, services, and care processes that are needed to have and sustain a high-volume program."

He and his colleagues found that very few of the 969 hospitals in the study met the volume guidelines established by the "Take the Volume Pledge" campaign designed to focus care in high-volume hospitals.

In fact, 77.8% of esophagectomies, 53.4% of pancreatectomies and 48.1% of proctectomies were done at low-volume facilities where the mortality risk, in theory, should be higher.

It was, but only in the hospitals that always had fewer than 20 esophageal and pancreatic resections per year and fewer than 15 rectal resections. These hospitals had significantly higher rates of 30-day and 90-day mortality.

For example, the 90-day mortality rate for pancreatectomy patients was 8.5% at hospitals with a consistently low surgical volume versus 5.3% at high-volume centers.

For most of the outcomes evaluated, hospitals that met the volume guidelines in at least one of the seven years that the researchers examined essentially scored the same.

For example, the 30-day mortality rate for esophageal resection was 37% lower in hospitals that performed a minimum of 20 such operations in only one of the seven years compared to the rate for hospitals where the annual volume never reached that level.

The fact that a hospital occasionally met the annual minimum "suggests that they may have (or had) resources similar to hospitals that are more consistently high volume and it is actually these resources and care processes that are associated with better patient outcomes after surgery," said Dr. Massarweh.

"What I think we need to do is understand what happens to patients at hospitals that have the best outcomes (whether they are high volume or not) and learn what resources and care processes are being provided that might not be available at other hospitals," he said. "If there are lessons we can learn that can help to improve the safety of surgical care more broadly, then that is a win for everyone."

It might also relieve a major concern about regional centers - that patients won't get good care if the travel time is too long. In the study, only 5.0% of patients had to travel at least 100 miles for their surgical care at the low-volume hospitals compared with 34.5% of patients treated at high-volume facilities.

"If a patient has to drive an extra couple of hours, this could be a significant burden or even a barrier to care. This may not be a big issue for patients with means, but for those without means this could be a real challenge," Dr. Massarweh said.

The elderly, minorities and Medicaid patients may be particularly affected.

The same issue of the journal includes an analysis of data from the CRITICS trial showing that patients who got their gastrectomy in a high-volume hospital had a survival rate that was 31% higher than patients treated at a low-volume facility.

The analysis included 494 patients with stomach cancer. All were treated at Dutch hospitals.

In low-volume hospitals, defined as doing fewer than 21 such surgeries per year, five-year overall survival was 46.1% compared with 59.2% in high-volume hospitals that performed 21 or more such operations annually (P=0.02).

The rates of disease-free survival were 27% higher in the higher-volume hospitals (P=0.04) but the difference was only significant when a multivariate analysis was done, perhaps because larger-volume hospitals got the most difficult cases.

The findings "emphasize the value of centralizing gastric cancer surgeries in the Western world," writes the team, led by Dr. Cornelis van deVelde of Leiden University Medical Center.

Dr. Massarweh said the two studies may not be comparable because the two countries' healthcare systems are so different and access to high-volume centers may be easier in the Netherlands, which is so small.

"In short, we now have nearly 2 decades of experience in describing the volume-outcome relationship," he said. "But, I have yet to see anyone who can put their finger on the main reasons why this relationship exists."

SOURCE: http://bit.ly/2S76r71 and http://bit.ly/2S76aRx Annals of Surgery, December 2019.