Lifestyle

Pain in Your Side That Does Not Go Away Can Be a Sign of Kidney Cancer. Other Signs to Know

By Curtis Jones · November 9, 2026

An ache in your side gets blamed on a lot of things. A pulled muscle, a bad mattress, too much yard work. Most of the time one of those explanations is right. But when the pain does not go away, it belongs on a short list of signs that health sources say can point to kidney cancer.

The kidneys are two fist-sized organs on either side of the backbone, just above the waist. MedlinePlus, the consumer health service of the National Library of Medicine, explains that tiny tubes inside them filter and clean the blood and make urine. Kidney cancer forms in the lining of those tubes.

One reason it can be missed is that it may cause no symptoms at first. MedlinePlus says symptoms may appear as the cancer grows. The Mayo Clinic says it is often hard to diagnose because it does not have clear signs in its early stages.

Age is part of the picture. MedlinePlus says kidney cancer becomes more likely as you get older. In an explainer video on its kidney cancer page, the Mayo Clinic says the average age of people diagnosed is 64 and that it is about twice as common in men as in women.

These are the signs MedlinePlus and the Mayo Clinic list.

Pain in your side or back that does not go away. MedlinePlus lists pain in your side that does not go away. Mayo describes pain in the side or back that does not go away. The key word in both is persistent.

Blood in the urine. Mayo says it may look pink, red or cola colored.

A lump in the abdomen. MedlinePlus includes this on its list.

Weight loss for no reason. Both sources list losing weight without trying.

Loss of appetite. This also appears on both lists.

Tiredness. Mayo lists tiredness, and its video describes it as persistent.

Fever or night sweats. These are mentioned in the Mayo Clinic video.

None of these signs means a person has cancer. Back pain and tiredness have many common causes. What matters is a change that sticks around or does not have an obvious explanation.

Mayo lists factors that may raise the risk, including older age, smoking, obesity, high blood pressure, certain inherited conditions and a family history of kidney cancer. MedlinePlus adds misusing pain medicines for a long time. Mayo also says the risk from smoking goes down after quitting.

If a doctor wants to look closer, MedlinePlus says the tests can include blood, urine and imaging tests, and sometimes a biopsy. Mayo says imaging such as ultrasound, CT scans and MRI can help show a tumor. It also notes that many kidney cancers are now found while they are still small and confined to the kidney, in part because imaging is used more often. Treatment depends on age, overall health and how advanced the cancer is.

The practical step is simple. Mayo’s advice is to make an appointment with a doctor or other health care professional if you have any symptoms that worry you. Before the visit, write down where the pain is, when it started, whether it comes and goes or stays, and anything else you have noticed, such as a change in your urine, your appetite or your weight. Only a clinician can sort out what those changes mean after an exam and any tests.

This article is for general information and is not medical advice. Talk with your doctor or health care provider about any symptoms that worry you. This article was produced with the assistance of AI and fact-checked against the sources cited by LightWave Reports.