Photo by Rhoda Baer
Cancer patient receiving treatment
New research suggests patients with acute myeloid leukemia (AML) may have a lower risk of early mortality if they receive treatment at a National Cancer Institute (NCI) cancer center.
In a study of AML patients in California, the risk of 60-day mortality was 53% lower among patients treated at NCI cancer centers than among those treated at other centers.
These findings were reported in Cancer.
“We found the early mortality, deaths less than 60 days after diagnosis, was significantly lower at the NCI-designated cancer centers compared to non-NCI-designated cancer centers in California,” said study author Brian Jonas, MD, PhD, of the University of California at Davis School of Medicine in Sacramento, California.
To conduct this study, Dr Jonas and his colleagues analyzed data from the California Cancer Registry and the California Office of Statewide Health Planning and Development Patient Discharge Database.
The California Cancer Registry provides sociodemographic and clinical data for all California cancer patients. The California Office of Statewide Health Planning and Development Patient Discharge Database has data on diagnoses and procedures for all hospital patients in California, excluding 14 Veterans Affairs and military hospitals.
Patients
The study included data on AML patients 18 and older who received inpatient chemotherapy between 1999 and 2014. There were 7007 patients, 1762 (25%) of whom were treated at NCI-designated cancer centers.
The median number of new AML patients per year was 13.5 (range, 0-43) at the NCI centers and 2 (range, 1-17) at non-NCI centers that admitted at least 1 patient with AML. More than half of the non-NCI centers had a median of 0 new AML patients per year.
NCI patients were more likely to be younger (≤65) than non-NCI patients (P<0.0001), to live in neighborhoods with higher socioeconomic status (P<0.0001), have fewer comorbidities (P<0.0001), and have public health insurance (P<0.0001).
Results
There were several types of complications that differed significantly between center types.
Patients treated at NCI centers were significantly more likely to have leukapheresis (5.5% vs 2.7%; P<0.001) and renal failure (22.8% vs 19.9%; P=0.010).
But they were significantly less likely to have respiratory failure (11.6% vs 14.3%; P=0.003) and cardiac arrest (1.1% vs 2.0%; P=0.014).
Sixty-day survival was significantly higher among NCI patients (88.0% vs 76.3%; P<0.001).
In an inverse-probability-weighted analysis adjusted for sociodemographic factors and comorbidities, treatment at an NCI center was associated with significantly lower early mortality, with an odds ratio (OR) of 0.46 (P<0.001).
This analysis also revealed a significant association between increased early mortality and major bleeding (OR=1.79, P<0.001), renal failure (OR=2.33, P<0.001), respiratory failure (OR=6.46, P<0.001), and cardiac arrest (OR=13.33, P<0.001).
For the most part, the impact of complications on early mortality did not differ significantly by treatment center.
The exception was respiratory failure. Patients with respiratory failure had a significantly greater risk of early mortality if they were treated at a non-NCI center (OR=9.48) than at an NCI center (OR=4.20).
Potential explanations
The researchers believe the variations in early mortality they observed point to inconsistent supportive care. However, more work must be done to fully understand the differences in care driving these issues.
“This is clearly provocative data that makes you want to understand exactly why,” Dr Jonas said. “We’re going to have to dive into that question in a more significant way.”
In the absence of data that could identify the exact causes, the researchers noted that other studies have shown higher patient volumes may contribute to better care.
“I see 60 or more AML cases per year,” Dr Jonas said. “High volume/low volume must play a role.”
The researchers believe other potential contributing factors could be access to clinical trials, better nursing ratios, and more sophisticated intensive care units.
The team hopes this research will spawn more intensive efforts to identify the causes that underlie variations in early mortality between hospital sites.
“This is a provocative and hopeful paper in terms of improving outcomes,” Dr Jonas said. “It sends a positive message that there are things we could probably do that could help everyone.”