ANN ARBOR, Mich. -- Kidney cancer patients who had only their tumor removed had better survival than patients who had their entire kidney removed, according to a new study from researchers at the University of Michigan Comprehensive Cancer Center.
After an average of five years, 25 percent of patients who had a so-called partial nephrectomy, in which only the tumor and a small margin of healthy tissue is removed, had died, while 42 percent of patients who had radical nephrectomy, in which the entire kidney is removed, had died, the study found. Results appear in the April 18 Journal of the American Medical Association.
"For patients who are candidates for partial nephrectomy, it should be the preferred treatment option. We found that patients who were younger or had pre-existing medical conditions benefited most from partial nephrectomy," said lead study author Hung-Jui Tan, M.D., a urology resident at the U-M Medical School.
The researchers looked at 7,138 Medicare beneficiaries with early stage kidney cancer up to eight years after treatment. Patients were equally likely to die of kidney cancer, regardless of the type of surgery they received, suggesting that each procedure was equally likely to cure the cancer. The survival discrepancy was found in the number of patients who died from any cause.
The study showed that if only seven patients chose partial nephrectomy over radical nephrectomy, it would save one extra life.
Early stage kidney cancers have become more common recently. These are often discovered by chance when patients receive an X-ray or CT scan for something unrelated.
"As more and more people are identified with these small, early stage cancers, there's more interest in understanding how best to treat these patients," says senior study author David C. Miller, M.D., M.P.H., assistant professor of urology at the U-M Medical School and member of U-M's Institute for Health Care Policy and Innovation.
The question, though, is whether partial nephrectomy - which is a more technically challenging procedure and potentially associated with more short-term complications - is preferable to radical nephrectomy. Removing a kidney can increase the risk of chronic kidney disease, which is associated with lipid disorders, cardiovascular disease and renal failure.
The debate is similar to breast cancer surgery, in which studies have found that lumpectomy plus radiation is comparable to mastectomy. While that choice often comes down to a cosmetic trade-off, the trade-off with kidney cancer is a potential higher risk of short-term complications with partial nephrectomy vs. avoiding chronic kidney disease in the long term.
"This study does not suggest every patient with early stage kidney cancer should get a partial nephrectomy. It supports the notion that we need to expand the use of partial nephrectomy and make it a preferred treatment choice for patients with small tumors as much as possible, to optimize long term survival," Miller says.
Kidney cancer statistics: 64,770 Americans will be diagnosed with kidney cancer this year and 13,570 will die from the disease, according to the American Cancer Society
Additional authors: Edward C. Norton, Ph.D.; Zaojun Ye, M.S.; and Khaled S. Hafez, M.D., from U-M; and John L. Gore, M.D., M.S., from the University of Washington
Funding: Agency for Healthcare Research and Quality, Edwin Beer Research Fellowship in Urology and Urology-Related Fields from the New York Academy of Medicine, University of Michigan Comprehensive Cancer Center
Reference: Journal of the American Medical Association, Vol. 307, No. 15, April 18, 2012
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