Symptoms may not appear until kidney cancer is in advanced stages. If you experience any symptoms, do not assume it is due to cancer. Many symptoms can be caused by other, less serious conditions. However, it is still important to discuss them with your doctor. Early detection and treatment improve outcomes for both cancer and other health conditions.

The most common symptoms include:

• Blood in the urine—The urine may appear brown or rust colored, or it may have visible blood clots in it. Any time blood appears in the urine, even if there is no pain, it should be reported to your doctor. Small amounts of blood may not be visible but may be detected incidentally during a routine urine test.
• Flank pain —Pain on the side of the body next to the backbone between the hips and ribs. Keep in mind that pain may be on one or both sides.
• Sensation of an abdominal mass .
• Fever of unknown origin—A persistent fever without any other signs of infection or without an apparent cause.
• Malaise —General feeling of illness.
• Loss of appetite —Can result in rapid, unintended weight loss.
• Fatigue —Extreme tiredness that may not be resolved with adequate rest. It also may be caused by anemia, a reduction in red blood cells.

The kidney has several functions that affect the entire body. Other vague symptoms, like swelling in the legs from fluid collection (edema), may occur. Kidney tumors can also trigger other syndromes in the body, called paraneoplastic syndromes. They occur when the tumor secretes hormones that influence bodily functions.