Q. What are the symptoms of kidney cancer?
A. The most common symptom, found in about half of all cases, is blood in the urine. However, only a minority of people with this symptom actually have cancer. In most cases it is caused by a kidney infection or kidney stones. Another quite common symptom is pain in the lower back or a swelling in the kidney area. Fatigue, weight loss, anaemia and sweating, which are the symptoms for many types of cancer, have also been reported.
Doesn't mention hard lump on back though -just swelling.