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5/15/2006

Cancer surgery, especially by experienced surgeons, saving more lives

Reports from several governmental and nongovernmental organizations show that overall cancer death rates have declined. While there are several factors that can account for this trend (for example, increased diagnosis of cancer at earlier stages), a new study by university and medical researchers found that cancer surgery has also become safer over time. Furthermore, there is a significant association between the number of operations performed by hospitals and by doctors and lower numbers of cancer deaths.

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According to reports from government and nongovernment organizations, overall cancer death rates declined each year by 1.1 percent from 1993 to 2001. A new study by university and medical researchers partially credits these statistics to the fact that cancer surgeries have gotten safer over time, as the number of surgeries performed by hospitals and by doctors has increased.

"Operative mortality rates for six specific cancers declined between the time periods 1988 to 1991 and 1997 to 2000 in the three states we studied," said Vivian Ho, an associate professor of economics at Rice University and a fellow in health economics at Rice's Baker Institute for Public Policy.

"In the same time periods, the number of hospital and doctor operations for those cancers rose over time, and the association between more operations and lower cancer death rates in hospitals was quite significant." The statistics reflect the total volume of surgeries performed at a particular hospital or the total number of operations performed by a particular doctor regardless of hospital location.

While prior research found that hospitals and surgeons performing more operations tended to have fewer cancer patient deaths, no study has examined the association between provider volume and trends in cancer surgery mortality over time. In an article titled "Trends in Hospital and Surgeon Volume and Operative Mortality for Cancer Surgery" in the Annals of Surgical Oncology, Ho and co-authors from the University of Alabama (Martin J. Heslin, Huifeng Yun and Lee Howard) report on the first comprehensive study to analyze data on six different types of cancer operations with an extensive sample of surgeons and hospitals in Florida, New Jersey and New York.

The researchers measured population-based trends in deaths from operations for colorectal cancer, specifically, colon cancer and cancer of the rectum, pulmonary lobectomies, pneumonectomies, esophagectomies and pancreaticoduodenectomies or the Whipple procedure over a 13-year period.

The smallest decline in inpatient mortality occurred in pulmonary lobectomy patients, specifically a decline of .8 percent from 4.1 percent between 1988 and 1991 to 3.3 percent from 1997 to 2000.   Esophagectomy patients whose rate of death declined from 14.5 percent to 10.5 percent over the sample period experienced the largest decrease.

Between the time periods 1988 to 1991 and 1997 to 2000, the volume of hospital and doctor operations increased for five of the six types of cancers, with the mean percentage increase equal to 24.3 percent for hospitals and 24.2 percent for surgeons. Further statistical analyses suggest that these increases in provider volume can explain the entire decline in operative mortality for pulmonary lobectomy and a substantial part of the mortality decline in four of the six other surgeries.

In light of their findings, Ho and her research colleagues urged the expansion of centralization efforts such as the Leapfrog Group, a coalition of large employers and other health-care purchasers who are encouraging patients and employees to seek out high-volume providers. They also believe that enforcement by states of Certificate of Need regulations, such as those for open-heart surgery and transplantation, might encourage even lower cancer mortality rates by limiting the number of hospitals performing few cancer operations.

According to Ho, Certificate of Need regulations were first introduced by the federal government in the 1970s, and they continue to be enforced by some states today. They forbid hospitals from providing certain operations unless they demonstrate to the state's public health department that there is sufficient need in the patient population to meet minimum volume standards.

A member of Rice's economics department and the university's James A. Baker III Institute for Public Policy since 2004, Ho researches and writes about the economics of health, specifically, the effects of economic incentives and regulations on the cost and quality of health care. Her studies, which also focus on competition and regulation in health-care markets, are widely published in such scholarly journals as The RAND Journal of Economics, the Journal of Health Economics, the American Economic Review and the Canadian Journal of Economics.

A graduate of Harvard University, where she received her undergraduate degree in economics, magna cum laude, Ho earned a graduate diploma in economics from Australian National University and her Ph.D. degree in economics from Stanford University.

For more information, contact Ho at vho@rice.edu or B.J. Almond in the Office of News and Media Relations at balmond@rice.edu.