As cancer grows in your body, it can affect you in several ways. The cancer can:
Push on nearby tissue and cause pain or block an important body function
Give off substances that interfere with other organs (called paraneoplastic syndromes)
For example, having a tumor near your bladder (the organ that holds your urine) can block your urine from coming out. Cancer inside your bones causes bone pain.
At first, cancer won’t cause any symptoms because it's just a tiny group of cells
As cancer grows, your symptoms will depend on where it's located
Some cancers can cause symptoms in parts of your body that aren’t close to your cancer
What are the symptoms of cancer?
Symptoms vary depending on the kind of cancer. Some cancers won't show symptoms until they have grown a lot. Others show symptoms at an early stage. Symptoms of cancer may include:
Pain
Most cancers are painless at first
As your cancer grows, you may have mild discomfort
Then, the pain gets worse as your cancer gets bigger
Not all cancers cause severe pain
Bleeding and blood clots
Cancer may cause bleeding inside your body, depending on where your cancer is located:
Cancer in your digestive tract can cause blood in your stool (poop)
Cancer in your urinary tract can cause blood in your urine
Cancer in your lungs can make you cough up blood
Cancer near a major artery can cause a hole in the artery that will bleed severely
Cancer in the bone marrow (the hollow insides of your bones, where blood cells are made) can stop your body from producing the cells that make blood clot
In advanced cancer, severe bleeding may cause death.
Many types of cancer increase the risk that you will develop blood clots in the veins in your legs. Blood clots in your leg veins sometimes break off and travel to a lung and block blood flow. This can cause serious difficulty breathing and sometimes death.
Weight loss and feeling weak
You may lose weight and become very thin
Food may make you feel sick to your stomach or you may have trouble swallowing
If you have anemia, you may feel very weak and tired as your cancer grows
Muscle and brain symptoms
If cancer grows into or squeezes your nerves or spinal cord, you may have:
Pain
Weakness
Changes in your sense of feeling, such as tingling
If cancer starts in or spreads to your brain, you may have:
Confusion
Dizziness
Headaches
Feel sick to your stomach
Changes in your vision
Seizures
Lung symptoms
If cancer squeezes or blocks the airways in your lungs you may have:
Trouble breathing
Cough
Pneumonia (a lung infection)