MONDAY, May 19 (HealthDay News) -- Compared to a decade ago, kidney cancer patients in the United States are much more likely to be diagnosed with smaller tumors in the earliest, most treatable stage of the disease, resulting in a slightly higher survival rate.
Researchers analyzed the records of more than 200,000 kidney cancer patients in the National Cancer Database and found that stage 1 kidney cancers increased from about 43 percent of all kidney cancer cases in 1993 to 57 percent in 2004, while rates of stages 2, 3 and 4 kidney cancers declined.
The average size of stage 1 tumors decreased from 4.1 centimeters in 1993 to 3.6 cm in 2003. Overall kidney cancer patient survival increased by 3.3 percent between 1993 and 2003. The current five-year survival rate for people with stage 1 kidney cancer is 88 percent of higher.
The study was published in the May issue of the journal Cancer.
"The changes in kidney cancer presentation are visible nationally and quite dramatic. If you are diagnosed with kidney cancer today, it is more likely to be at the earliest 'stage 1' level as opposed to more advanced 'stage 2, 3, or 4' just a decade ago," senior author Dr. Christopher Kane, chief of urology at the University of California, San Diego, Medical Center and the Moores UCSD Cancer Center, said in a prepared statement.
Kane and his colleagues suspect that increased detection of early-stage kidney cancer -- which often has no symptoms -- may be due to more widespread use of such medical imaging as ultrasound, CT scans and MRIs to evaluate other medical conditions.
"What we are seeing is that gynecologic or abdominal imaging to evaluate pain or other complaints is picking up other forms of disease such as kidney cancer," Kane said. "The increased and widespread use of medical imaging in the United States is helping to diagnose (kidney) cancer in its non-symptomatic stages when it is easier to treat successfully."
"The message to patients is not to go out and request an ultrasound or CT scan. Keep in mind that this is a rare form of cancer. However, if abdominal imaging is done, and a mass or masses in the kidney are recognized, evaluation by a urologist is recommended," Kane said.
Kidney cancer accounts for about 3 percent of all cancer deaths in the United States, with about 12,890 deaths in 2007. In the early stages, it rarely causes any signs or symptoms. In later stages, the disease may cause symptoms such as blood in the urine, back pain, weight loss, fatigue and intermittent fever.
The American Urological Association has more about kidney cancer.