Is kidney cancer painful? What pain does — and does not — tell you

Usually not. Most kidney cancers cause no pain at all, particularly while they are small, which is why so many are picked up by chance on a scan arranged for something else. There is room in the abdomen for a kidney tumour to grow before it stretches the capsule around the kidney or presses on anything that hurts. Pain, when it does appear, tends to arrive late and to be a dull, steady, one-sided ache rather than a sharp one. So the absence of pain is not reassurance, and the presence of pain is far more often a muscle, a stone or an infection than a cancer.

There is no fixed stage at which pain begins, and many people have none at any stage. Pain becomes more likely once a tumour is large enough to stretch the tough capsule around the kidney, to press on nearby structures, or to bleed into itself. That is generally a later situation than the small, incidentally discovered tumours that account for a great many kidney cancer diagnoses today. Because pain tracks size and position rather than how aggressive a tumour is, a painful tumour is not automatically a more dangerous one, and a painless tumour is not automatically an early one. Only imaging can answer that.

When a kidney tumour does cause pain, people usually describe a dull, heavy, constant ache on one side, in the flank between the lowest rib and the top of the hip. It does not shift when you change position, it is not clearly worse for bending or lifting, and it does not settle over weeks. That is quite different from a kidney stone, which typically causes severe pain in waves that travels towards the groin, and different again from muscular pain, which usually eases with rest. Our page on persistent flank or side pain and kidney cancer sets those patterns out side by side.

Yes, and that is the usual situation rather than the exception. A kidney cancer can grow for a long time with no pain, no blood in the urine and no change you would notice, which is exactly why so many are found only when an ultrasound or CT is done for an unrelated complaint. That is a good reason not to use pain as your test. If you have a reason to be concerned, such as blood in the urine even once, a strong family history, or an ache on one side that has not settled, ask for imaging rather than waiting for pain to tell you something is wrong.

Less than most people fear, and pain is planned for rather than left to chance. A kidney biopsy is done under local anaesthetic and feels more like pressure than pain. Surgery to remove a tumour or a kidney, and ablation treatments, are coordinated with specialist urology, uro-oncology and interventional radiology partner centres, and soreness afterwards is managed with a written pain plan. The systemic treatments led in-house at CION, immunotherapy and targeted tablet therapy, are not painful to receive, although class side effects such as sore hands and feet or joint aches can occur and are managed actively. Radiation itself is painless while it is being delivered.

If kidney cancer has spread, pain can come from the new site rather than from the kidney. Spread to bone can cause a deep, persistent ache in the spine, hip, rib or thigh that is often worse at night and does not ease with rest. Spread to the lung is more likely to cause breathlessness or a cough than pain. New, unexplained, persistent bone pain in someone with a known kidney cancer should always be reported rather than endured, because it can be assessed and treated in its own right, including with focused radiation aimed specifically at relieving the pain.