Now a new study by University of Michigan Health System researchers finds that patients undergoing surgery for kidney cancer are less likely to die at hospitals that perform the operations frequently. The study appears in the May issue of Urology.
In the first study to look nationwide at the relationship between surgical volume and mortality for nephrectomy for cancer, the researchers found patients faced a 32 percent lower risk of dying at high-volume hospitals compared to hospitals that performed fewer nephrectomies.
"Following nephrectomy performed for cancer diagnoses, there were fewer in hospital deaths at hospitals that performed more of these surgeries. Our study confirms what others have found in different conditions, that surgical experience has a significant impact on outcomes," says senior study author John Wei, M.D., assistant professor of Urology at U-M Medical School.
The researchers looked at 20,765 patients who underwent kidney surgery because of cancer at 962 hospitals from 1993-1997, based on data from the Nationwide Inpatient Sample, a random sample of 20 percent of all hospital discharges in the United States maintained by the Agency for Health Care Research and Quality. Patients underwent radical nephrectomy (complete removal of the kidney), nephroureterectomy (removal of the kidney and ureter) or partial nephrectomy.
The participating hospitals were classified according to the number of nephrectomies performed each year as low-volume, medium-volume or high-volume.
Overall, 1.39 percent of patients died in the hospital following nephrectomy. Patients at high-volume hospitals had nearly one-third lower risk of dying compared to patients at medium-volume hospitals, and one-quarter lower risk of dying compared to patients at low-volume hospitals. Older patients, patients who underwent emergency surgery and patients with chronic pulmonary disease or whose cancer had spread faced a higher risk of dying in the hospital after surgery.
High-volume hospitals were more likely to perform partial nephrectomies, a newer procedure that's equally effective as radical nephrectomy at controlling cancer. Patients who had this procedure at a high-volume hospital saw better outcomes.
The researchers did not find any difference in the length of hospital stay based on surgery volumes, suggesting that other factors such as age, gender and urgent hospital admission have a stronger effect on length of stay.
Based on this and other studies showing a link between surgical volumes and lower mortality rates, some organizations have made efforts to reduce the variation between hospitals.
"Patients should keep in mind that with nephrectomy for cancer, other factors besides surgical volumes can affect the outcome, such as age or the size of the tumor; therefore, we cannot specify an absolute cutoff for the number of surgeries that hospitals need to perform to be considered 'adequate' experience," says lead study author David Taub, M.D., a Urology resident at U-M Medical School.
In addition to Wei and Taub, study authors were David Miller, M.D., and James Montie, M.D., of the U-M Department of Urology, John Cowan, M.D., from Neurosurgery, and Justin Dimick, M.D., from Surgery.