THURSDAY, Sept. 21, 2006 (HealthDay News) -- While more kidney cancers are being diagnosed and treated early, the number of deaths from the disease continues to increase, University of Michigan researchers report.
The fact that the number of cases has been growing is largely due to the detection of small, presumably curable, tumors, so the scientists said they aren't exactly sure why so many are still dying.
However, one expert noted the trend might be explained by the lack of effective chemotherapy drugs to give kidney cancer patients once they have had surgery to remove tumors.
Kidney cancer is the third most common cancer of the reproductive and urinary systems. There will be some 38,890 new cases of kidney cancer in the United States this year, and some 12,840 people will die from the disease, the American Cancer Society estimates.
The latest research was published in the Sept. 20 issue of the Journal of the National Cancer Institute.
"With increased early detection and treatment of small tumors, we would expect to see a decrease in mortality associated with kidney cancer," study senior author Dr. Brent K. Hollenbeck said in a statement. "Surprisingly, that's not what we found. Our research shows that an increase in detection and treatment is not leading to a reduction in the kidney cancer mortality rate."
In the study, Hollenbeck's team collected data on 34,503 patients who had kidney cancer.
They found that from 1983 to 2002, the incidence of kidney cancer increased 52 percent, from 7.1 to 10.8 cases per 100,000 people. The biggest increase was seen in the number of people with small tumors, roughly 2 centimeters to 4 centimeters in size.
However, death rates also went up, most notably among those with tumors larger than 7 centimeters. Overall, deaths from kidney cancer rose from 1.2 to 3.2 per 100,000 people, the researchers noted.
These findings are partly explained by increasing incidence of larger, more lethal tumors. "While more and more small, detectable kidney tumors are being treated, the absolute number of patients with larger, lethal masses has not decreased. And it is these larger, lethal masses that seem to mainly affect mortality," study co-author Dr. John M. Hollingsworth said in a statement.
In addition, some of the smaller tumors may not need surgical removal, the researchers speculated.
"We're not saying that surgery for patients with small renal masses is inappropriate," Hollingsworth said. "Our findings, however, show that their increased treatment has not diminished kidney cancer mortality. This calls to question the effectiveness of our current treatment strategy. Perhaps there are some patients with small kidney tumors for whom surgery is not the best option."
However, one expert thinks the high death rate can be attributed to a lack of chemotherapy drugs to treat patients after they have surgery.
Dr. Herman Kattlove, a medical editor at the American Cancer Society, disagreed that patients with small kidney tumors shouldn't have surgery. "The procedure is safe, and often the kidney can be preserved," he said.
"The problem is that there aren't any good drugs for kidney cancer. It is not a tumor that is very responsive," Kattlove said. "We need to find better drugs to deal with this disease in the postoperative state, before it spreads."
More information
The American Cancer Society can tell you more about kidney cancer.
