Marlene Busko

May 09, 2014

TORONTO — Thirty-day mortality following lung cancer surgery has greatly decreased in the United States during the past decades, and not unexpectedly, it is lowest in high-volume hospitals, according to new research.

However, the study also identified, perhaps surprisingly, that mortality after lung cancer surgery continued to increase to 90 days.

"The overall 30-day mortality at more than 1200 hospitals that were accredited by the Commission on Cancer [COC] was low: 2.8%," Christopher M. Pezzi, MD, from Abington Memorial Hospital, in Pennsylvania, reported here at the American Association for Thoracic Surgery (AATS) Annual Meeting 2014. "This…is lower than was reported from the highest-volume hospitals just 15 years ago [and] is a very positive message for lung cancer surgery at the COC-approved hospitals."

However, "perhaps the most important finding" was that the 90-day mortality following lung cancer surgery was nearly double the rate at 30 days. This has not been examined in the past, because traditionally, mortality rates have been reported at 30 days. The increase in mortality from 30 days to 90 days occurred at both low- and high-volume hospitals, although it was less likely at the busiest hospitals, Dr. Pezzi noted.

Better Outcomes at Busier Hospitals?

Since the 1960s, 30-day mortality rates after lung cancer surgery have greatly declined, according to 8 diverse studies, Dr. Pezzi explained.

The National Cancer Data Base, which captures about 82% of all new lung cancer cases in the United States, provided an opportunity to evaluate hospital surgical volume and mortality not just at 30 days but also at 90 days.

The researchers identified more than 120,000 major, cancer-related pulmonary resections performed at COC-approved hospitals from 2007 to 2011. Almost all (93%) of the operations were single lobectomies or bilobectomies; 7% were pneumonectomies. Wedge resections or resections of less than 1 lobe were excluded.

At 30 days after the surgery, 2.8% of patients had died, and from 30 to 90 days after surgery, an additional 2.6% of the patients had died.

About 9% of the major lung resections were performed at hospitals with fewer than 10 such cases a year (low-volume centers). At the other end of the spectrum, about 11% of the operations were performed at hospitals that did more than 90 such cases a year (high-volume centers).

The 30-day mortality rate was 3.7% in low-volume centers vs 1.7% in high-volume centers. This rate was also greater in patients who were older, male, had a lower income, were not covered by private insurance, lived in the southern United States, or had a higher cancer stage, pneumonectomy, prior primary cancer, or neoadjuvant radiation therapy.

Similar but smaller differences in mortality rates between low- and high-volume centers were seen at 30 to 90 days after surgery.

"The mortality rate after pneumonectomy is about 3 times higher than after lobectomy, and the pneumonectomy rate has continued to decline through the years, [which is] a major contributor to the lower overall mortality of lung cancer surgery," Dr. Pezzi added.

Although the study did not determine a threshold number of cases linked with better survival, "I would suggest that more than about 30 cases a year puts you in a more favorable group," he said.

Study limitations include a lack of information about the cause of death, he acknowledged.

"Eye-Opening" 90-Day Mortality

"The authors have identified a modest, and I underline 'modest,' relationship [between] mortality risk" in low- vs high-volume centers, the assigned discussant, Cameron D. Wright, MD, Massachusetts General Hospital, Boston, said.

"Of more interest to me is the change in mortality [from 30 days until 90 days], essentially doubling the 30-day mortality [rate]. We need to find out what happens to our patients in this vulnerable period of time after they are discharged, to see if we can mitigate this risk," he added.

In the question period after the presentation, a surgeon from Poland asked why 90 surgeries a year defined high-volume hospitals. In Europe, high-volume centers perform a least 200 cases a year, and 90 cases would mean that 3 surgeons would each do fewer than a case a week. Dr. Pezzi replied that only 21 of the 1200 hospitals had a workload of at least 90 major lung surgeries a year.

This paper "documented how mortality has been dropping over the past 25 years, because of the pervasion of minimally invasive technique," Michael T. Jaklitsch, MD, Brigham and Women's Hospital, Boston, commented to Medscape Medical News after the presentation. The importance of 90-day outcomes in lung cancer surgery — which is being looked at in esophageal cancer as well — was "eye-opening," he said.

Dr. Pezzi, Dr. Wright, and Dr. Jaklitsch have disclosed no relevant financial relationships.

American Association for Thoracic Surgery (AATS) Annual Meeting 2014. Plenary scientific session. Presented April 29, 2014.


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