Kidney Cancer Survival on the Rise
Tumors Spotted Earlier, Study Confirms
May 19, 2008 -- More and more kidney cancers in the United States are being diagnosed at early, highly treatable stages, and more patients are surviving the disease, a national study confirms.
In just over a decade, between 1993 and 2004, the percentage of kidney cancers diagnosed at the earliest "stage I" level rose from 43% to 57%.
The average size of a stage I tumor decreased from 4.1 cm to 3.6 cm during roughly the same period. There was a 3.3% increase in survival among patients of all stages from 1993 to 1998.
Calling the findings "quite dramatic," the study's lead researcher tells WebMD that they were also something of a surprise.
About 50,000 new cases of kidney cancers are discovered each year in the United States.
"A 3% increase in survival may seem like a small number, but it represents a lot of patients," says Christopher J. Kane, MD, who is chief of urology at the University of California, San Diego.
More Kidney Cancers, Fewer Deaths
The overall incidence of kidney cancer is on the rise in the U.S., but much of the increase has been seen in early-stage disease.
Kane says there had been signs that kidney cancers were being diagnosed earlier, but the magnitude of the change has not been known.
In the largest study ever to address the question, the researchers reviewed the medical records of more than 200,000 kidney cancer patients registered in a national cancer database.
The findings confirm that a smaller percentage of cancers are being discovered after the disease has spread beyond the kidneys.
A 14% rise in the diagnoses of the earliest, stage I cancers between 1993 and 2004 was accompanied by an 8% decline in the deadliest stage IV cancers.
The five-year survival for stage IV disease is about 10%, compared to close to 90% for stage I kidney cancer.
Roughly 19% of the kidney cancers diagnosed in the U.S. in 2004 involved stage IV disease, compared to about 27% in 1993.
During this time, the proportion of stage II and stage III cancers also declined, from 12% to 10% and 18% to 14%, respectively.
"This evidence suggests that all cases are migrating from later stages to earlier stages over the period of observation," Kane and colleagues write in the online version of the journal Cancer.