Serious Warning Signs Of Kidney Cancer

August 2, 2023

The kidneys are located in the upper back region on either side of the spine. Adrenal glands sit on top of the kidneys and are both encapsulated along with fat inside of a fibrous layer called Gerota's fascia. Kidneys filter the blood of waste products, salt, and excess water. Kidneys produce hormones that influence blood pressure, red blood cell production, and electrolyte regulation. Kidney cancer is a malignancy that originates in the kidney tissues. The most common form of kidney cancer is renal cell carcinoma. Transitional cell carcinoma is a kidney cancer that begins in the renal pelvis lining or tissue where the ureters merge into the kidneys. Wilms' tumor is a kidney cancer almost exclusive to children. A renal sarcoma is a rare malignancy that originates in the connective tissues or blood vessels of the kidney.

Blood In Urine

An individual who has blood in their urine, also called hematuria, may be affected by kidney cancer. Blood in the urine can be visible with the naked eye, called gross hematuria, or could only be visible at the microscopic level, which is called microscopic hematuria. Gross hematuria in an affected individual appears as urine with a cola, red, or pink coloring to it. It does not take a significant amount of blood to change the color of an individual's urine. Hematuria that occurs due to kidney cancer often does not manifest when the malignancy is in its early stages and easy to treat.

Kidney cancer can metastasize to the bladder, prostate, uterus, and other neighboring structures before it produces this symptom and others. Kidney cancer that infiltrates to the inner parts of the kidney can cause damage to thousands of the tiny blood filters, allowing for the leakage of red blood cells into the urine. Kidney cancer can spread into the ureters and bladder, causing damage to its lining and the blood vessels that supply it with oxygenated blood. This type of damage from cancerous growth can cause an individual to have blood in their urine.

Persistent Flank Pain

Pain or discomfort in the upper back and abdomen that spreads to the sides and originates the region below the ribs and above the pelvis is called flank pain. When flank pain manifests due to kidney cancer, it typically only occurs in one side of the body. A growing tumor in or around the kidney can press against one of the ureters to the point where urine can no longer pass through it. The tumor may metastasize into the area where the ureter meets the kidney, down and into the ureter itself, or into the area where the other end of the ureter meets the bladder. One or more of these mechanisms can cause a blockage in the healthy flow of urine. The urine then builds up in the kidney, causing kidney swelling and tissue damage. This kidney damage and subsequent inflammation can cause an affected individual to feel persistent flank pain. A growing tumor in the kidney can metastasize into the main vessels that supply the kidney with oxygenated blood and nutrients. Should cancerous growths obstruct blood flow in these vessels, oxygen-deprived kidney tissues begin to die. This is called a renal infarct and can cause the patient to feel flank pain.

Loss Of Appetite

Loss of appetite is the term used to describe the absence of an affected individual's desire to eat food. Appetite loss occurs in individuals affected by numerous types of cancer, including kidney cancer. Changes in an affected individual's metabolism can occur due to the adverse effects malignancy has on the body. Cancerous cells in the kidneys impair homeostatic functions that cause disruptions in the natural process of hunger signaling. Cells cannot produce enough usable cellular energy to supply all of the malignant cells and healthy cells in the body, causing the patient to feel weak and fatigued.

Appetite loss can occur as a result of a lack of energy to carry out the task of consuming food. Furthermore, cancerous tumors of the kidneys can cause an inappropriate buildup of certain toxins in the blood that would otherwise be filtered out by a kidney that does not contain cancer. These toxins interrupt normal metabolic processes and produce symptoms of nausea and vomiting due to organ toxicity. Pain, nausea, and vomiting are common causes of appetite loss.

Intermittent Fever

Specific types of cancer are known to liberate white blood cells called cytokines that induce a fever in affected individuals. A fever occurs when the immune system components signal a change in the internal thermostat of the body. While it does not help kill off cancerous cells, it is a defense mechanism that helps kill off infection-causing pathogens. The cells that trigger this process in response to a harmful pathogen are the same cells certain cancers are known to liberate. Specific cytokines known to produce a fever in individuals affected by malignant tumors include interleukin-6, interleukin-2, and TNF. There is no definitive pattern that occurs with this recurrent fever in kidney cancer patients. Fever may occur during the day or at night, and severe night sweats that prompt an affected individual to get up and change their bedding are a significant indication. The fever that occurs with cancer is mostly low-grade and not severe, although episodes of high fever are not uncommon either.


All cancers, including kidney cancer, are known to produce fatigue because of the general effects that malignancy alone has on the healthy cells of the body. Nutrients from the food an individual consumes are absorbed and packaged up so they can be delivered to cells around the body. The nutrients that arrive in the cell are used in a series of complex chemical transformations to produce a form of energy that can be used by the cell called ATP. That ATP is used to fuel the differentiated and respective functions of the cell. The cell can perform without adequate ATP for a short period but will begin to shut down at a certain point. Although cancerous cells serve no beneficial function in the human body, they still require nutrients to produce their source of energy. Nutrients consumed by an affected individual are distributed to healthy and malignant cells around the body, allowing the cancerous cells to take up a significant portion of them. Fewer nutrients are left to go around to healthy cells, causing a shortage of ATP. The brain detects this and redistributes nutrients to cells that are vital for survival instead of those of other non-vital tissues. The lack of ATP overall and the weakness caused by redistribution causes a kidney cancer patient to feel very fatigued.

Unusual Weight Loss

Unusual weight loss is a common symptom of various types of cancer, including kidney cancer. A loss of total body mass occurs in an individual when their energy balance shifts from neutral or positive to negative. Energy balance is a term used to describe a ratio that compares the number of calories an individual burns to the number of calories they take in. A total increase in body mass occurs when an individual takes in a greater number of calories than their body is burning, and a total decrease in body mass occurs when they take in fewer calories than what their body is using. Healthy cells require calories and glucose to carry out their differentiated functions and to produce usable cellular energy. Cancerous cells in the body also require glucose and calories to carry out their functions. Cancerous cells use calories and glucose at a much faster rate than healthy cells do because they are growing and duplicating rapidly. Weight loss occurs because the growing malignant cells are using up more calories than the individual is taking in.


Anemia is a condition where an individual does not have an adequate amount of functioning red blood cells in their body. Bone marrow produces red blood cells when a certain hormone is released that tells it to do so. The hormone responsible for commanding the bone marrow to produce more red blood cells is referred to as erythropoietin. The organs responsible for the production of erythropoietin are the kidneys. A healthy individual's kidneys know to make erythropoietin when the oxygen level in the blood they are filtering becomes too low. An individual who develops kidney cancer can experience symptoms of low oxygen in the blood, but their kidneys may be unable to function normally and do not produce any erythropoietin in response to the low oxygen concentration. In these conditions, the affected individual's bone marrow fails to produce enough red blood cells in the body. This malfunction causes an individual with kidney cancer to develop anemia.

Leg And Ankle Swelling

Leg and ankle swelling is also referred to as edema in the medical community. Swelling in the lower extremities of the body occurs when extra fluid is forced through the veins from the bloodstream. Without this mechanism in place, an individual's extremely high blood pressure would cause the veins to become severely damaged and ruptured. Fluids forced from the veins accumulates in the neighboring tissues and is pulled toward the lower extremities by the force of gravity. Fluid balance in the body is regulated by the pituitary gland, adrenal glands, and kidneys. The kidneys are responsible for drawing excess fluid from the blood for excretion through the urine when certain hormones are released by the aforementioned glands. The kidneys do this by drawing sodium from the blood, as fluids follow levels of sodium and vice versa. The kidneys of a kidney cancer patient may be working too poorly to remove excess fluid from the blood, causing edema in their legs and ankles.

Bone Pain

An individual who has kidney cancer that spreads from the kidneys to another part of their body is considered to have metastatic kidney cancer. One of the most common parts of the body affected by metastatic kidney cancer is the bones. Around one-third of individuals diagnosed with renal cell carcinoma will be diagnosed with cancer in their bones. When an individual develops cancer in their bones, the delicate balance of bone tissue breakdown and rebuilding is disrupted. Cancerous cells can cause the bones to become excessively weak and break, which causes an affected individual to feel bone pain as a symptom. The exact reason why kidney cancer tends to spread to the bone tissues in many cases is not clear, but it is thought to be associated with the close proximity of the kidneys to large bones like the spinal column and pelvic bone.

Shortness Of Breath

Along with the bones, the lungs are also a common part of the body for kidney cancer to spread to. When cancer spreads from the kidneys to the lung tissues, it causes damage to the air sacs that facilitate the exchange of carbon dioxide and oxygen in their blood. When the air sacs in the lungs (alveoli) are functionally or structurally compromised, the surface area inside of the lung becomes reduced. Reduced lung surface area means the blood moving through the capillaries in the lungs does not get enough oxygen to meet the demand of the individual's body. When the oxygen concentration in an individual's blood is too low, their brain tells their lungs to work harder and faster to help increase blood oxygen levels. When the lungs are working under this kind of stress, the affected individual will experience symptoms related to poor lung function like shortness of breath.

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